JP2007263804A - Radiation measuring device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure a radiation doze of a measuring object such as a pipe accurately, precisely and efficiently, in a radiation measuring device for measuring the radiation doze of the measuring object emitting a radiation. <P>SOLUTION: This device has a measuring object storage part 11 for storing the measuring object P emitting the radiation together with gas; the first ion collection part 15 for collecting ions in the gas flowing out of the measuring object storage part 11; the first high-voltage power source device 17 for applying a voltage to an electrode of the first ion collection part 15; fans 20a, 20b for sending the gas in the measuring object storage part 11 to the first ion collection part 15, and returning the gas sent to the first ion collection part 15 to the measuring object storage part 11, to thereby circulate the gas; the first current measuring part 21 for measuring the ions collected by the first ion collection part 15 as a current; a shape/correction coefficient acquisition part 38 for acquiring a correction coefficient corresponding to the shape of the measuring object P based on a correspondence table between the shape of the measuring object P and a correction coefficient of sensitivity; and a current correction part 22 for measuring the radiation doze of the measuring object P by correcting a current value by the correction coefficient outputted from the shape/correction coefficient acquisition part 38. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radiation measurement apparatus and a radiation measurement method for measuring radiation by current measurement using an ionization effect by radiation.

  In general, in a radiation measuring apparatus and a radiation measuring method, a gas in the vicinity thereof is ionized by radiation emitted from an object to be measured such as waste, and an ion pair is generated. The ion is generated for several seconds to several tens of seconds. It has a lifetime and exists in the vicinity of the measurement object during that period. If the number of ions of the generated ions is measured as a current, the intensity of radiation can be obtained.

The following documents are disclosed as conventional techniques of a radiation measuring apparatus and a radiation measuring method using this principle.
Japanese Patent No. 3408543 JP 2003-337175 A JP 2003-194946 A Satoshi Naito, Akira Sano, Mikio Izumi, et al., “Development of ion current prediction model for ionized pneumatic transport measurement of α-rays”, Japanese Atomic Energy Society Journal, Vol. 4, No. 1, pp. 7 “2005”

  However, the 1st subject of a prior art is a point to which the ionic current measured changes with the shape and material of the measurement object accommodated in a measurement object accommodating part, or the gas state of the place where it is installed. That is, when there is contamination inside the pipe as the measurement object, the amount of ions transported to the ion collector is different from that when there is contamination on the surface, and the current is measured as a different current.

  When the measurement object is a charged substance, ionized ions are adsorbed and the amount of ions transported to the detector is reduced. In addition, a pollutant commonly referred to as aerosol is suspended in the gas. Depending on the amount, the ion annihilation time and the like vary, and the measured current changes. In particular, from the viewpoint of detection of contamination, it is essential to take appropriate measures since the contamination is missed when the ion current decreases.

  A second problem of the prior art is that the minimum amount (lower limit) of contamination that can be detected changes as the amount of BG (Back Ground) ions in the ion gas changes. Factors that change the amount of BG ions include changes in radon concentration, which is a radioactive gas in the gas, and fluctuations in space radiation. In particular, the radon concentration varies depending on the installation location of the apparatus and the weather such as rain. In addition, radon concentration is considered to tend to increase radon from fission materials such as uranium in facilities where α contamination is considered, and it is important to suppress fluctuations.

  In addition, when the radiation to be measured is α rays or heavy charged particles, the number density immediately after the generation of ionized ions is very large. For this reason, about several tens of percent of ions disappear immediately after generation due to recombination of positive and negative ions proportional to the square of the ion number density. Therefore, the amount of ions transported to the detector decreases, and the measurement current decreases and fluctuates, so that the measurement accuracy of radiation decreases, which is a third problem of the prior art.

  Furthermore, since the relationship between the measurement current and radiation differs depending on the type of radiation (α-ray, β-ray, γ-ray, etc.), it is necessary to discriminate the type of radiation in order to accurately measure the radiation. However, it is a fourth problem of the prior art that the type of radiation cannot be distinguished only from the measurement current.

  In addition to the radiation from the subject, the measurement current includes a current caused by BG ions ionized by natural radiation (such as radon, cosmic rays, and environmental γ rays). The BG ion becomes noise in measurement and lowers the measurement accuracy of radioactivity, which is a fifth problem of the prior art.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a radiation measuring apparatus and a radiation measuring method capable of accurately and accurately measuring the radiation dose of a measurement object. .

  In order to solve the above-described problems, the radiation measurement apparatus according to the present invention includes a measurement object storage unit that stores a measurement target that emits radiation together with gas, and the measurement target storage. An ion collector that collects ions in the gas flowing out from the unit, a power supply unit that applies a voltage to the electrode of the ion collector, and the gas in the measurement object storage unit is sent to the ion collector, A gas transport unit that returns the gas sent to the ion collection unit to the measurement object storage unit and circulates the gas, a current measurement unit that measures the ions collected by the ion collection unit, and the measurement Based on a correspondence table between the shape of the object and the correction coefficient of sensitivity, a correction coefficient acquisition unit that acquires a correction coefficient corresponding to the shape of the measurement object, and the current value output from the current measurement unit is corrected. Corrected by the correction coefficient output from the number acquisition unit, and a current correcting unit that measures the radiation amount of the measurement object from the corrected current value.

  In order to solve the above-described problems, the radiation measurement apparatus according to the present invention includes a measurement object storage unit that stores a measurement target that emits radiation together with a gas, and the measurement target storage. An ion collector that collects ions in the gas flowing out from the unit, a power supply unit that applies a voltage to the electrode of the ion collector, and the gas in the measurement object storage unit is sent to the ion collector, A gas transport unit that returns the gas sent to the ion collection unit to the measurement object storage unit and circulates the gas, a current measurement unit that measures the ions collected by the ion collection unit, and the measurement Based on a correspondence table between the charge amount of the object and the correction coefficient of sensitivity, a correction coefficient acquisition unit that acquires a correction coefficient of sensitivity corresponding to the charge amount of the measurement object, and a current output from the current measurement unit value The corrected by the correction coefficient output from the correction coefficient acquisition unit, and a current correcting unit that measures the radiation amount of the measurement object from the corrected current value.

  In order to solve the above-described problem, the radiation measuring apparatus according to the present invention includes a charging state determination unit that determines a charging state of a measurement object that emits radiation, and the charging state determination unit. According to the charged state of the measurement object, the charge removal unit for removing the charge of the measurement object, the measurement object storage part for storing the measurement object together with the gas, and the gas that has flowed out of the measurement object storage part An ion collector that collects ions therein, a power supply unit that applies a voltage to the electrode of the ion collector, and the gas in the measurement object storage unit is sent to the ion collector and to the ion collector. A gas transport unit that circulates the gas by returning the generated gas to the measurement object storage unit, a current measurement unit that measures the ions collected by the ion collection unit as current, and the current measurement unit And a current correcting unit that measures the radiation amount of the measurement object from the measured current value.

  In order to solve the above-described problem, the radiation measurement apparatus according to the present invention includes a measurement object storage unit that stores a measurement target that emits radiation together with a gas, and the measurement target storage. An ion collector that collects ions in the gas flowing out from the unit, a power supply unit that applies a voltage to the electrode of the ion collector, and the gas in the measurement object storage unit is sent to the ion collector, A gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit, a radioactive gas collection unit that collects the radioactive gas in the gas, and the ion collection unit A current measurement unit that measures the ions collected in step 1 as a current, and a current correction unit that measures the radiation dose of the measurement object from the current value measured by the current measurement unit.

  In order to solve the above-described problem, the radiation measurement apparatus according to the present invention includes a measurement object storage unit that stores a measurement target that emits radiation together with a gas, and the measurement target storage. An ion collector that collects ions in the gas flowing out from the unit, a power supply unit that applies a voltage to the electrode of the ion collector, and the gas in the measurement object storage unit is sent to the ion collector, A gas transport unit that returns the gas sent to the ion collection unit to the measurement object storage unit and circulates the gas; a temperature and humidity control unit that controls at least one of temperature and humidity of the gas; and the ion A current measurement unit that measures the ions collected by the collection unit as current; and a current correction unit that measures the radiation dose of the measurement object from the current value measured by the current measurement unit.

  In order to solve the above-described problem, the radiation measuring apparatus according to the present invention includes, as described in claim 11, a measuring object storage unit that stores a measuring object that emits radiation together with gas, and the measuring object storage. An ion collector that collects ions in the gas flowing out from the unit, a power supply unit that applies a voltage to the electrode of the ion collector, and the gas in the measurement object storage unit is sent to the ion collector, The gas sent to the ion collection unit is returned to the measurement object storage unit to circulate the gas, the gas exchange unit for replacing a part of the gas, and the ions collected by the ion collection unit A current measuring unit that measures the radiation dose of the measurement object from the current value measured by the current measuring unit.

  In order to solve the above-described problem, the radiation measurement apparatus according to the present invention includes a measurement object storage unit that stores a measurement target that emits radiation together with a gas, and the measurement target storage. A first ion collecting unit that collects ions in the gas flowing out from the unit, a first power supply unit that applies a voltage to an electrode of the first ion collecting unit, and the gas in the measurement object storage unit. A gas transport unit that sends the gas sent to the ion collection unit to the measurement object storage unit and circulates the gas, and the ions collected by the first ion collection unit A first current measuring unit that measures as follows; a second ion collecting unit that collects ions in the gas before activation of the first power supply unit; and a second ion collection prior to activation of the first power supply unit. Apply voltage to the electrodes That has a second power supply unit, and a current correction unit that measures the radiation amount of the measurement object from the current value measured by the first current measuring unit.

  In order to solve the above-described problem, the radiation measuring apparatus according to the present invention provides a grounding portion for grounding a measurement target that emits radiation, and a measurement that houses the measurement target together with a gas, as described in claim 16. An object storage unit, a first ion collection unit that collects ions in the gas flowing out of the measurement object storage unit, a first power supply unit that applies a voltage to an electrode of the first ion collection unit, and An electric field shield part that is provided inside a measurement object container, shields the required measurement object in an electric field, and guides ions in the measurement object container in the direction of the first ion collector; and the measurement object A third ion collector that collects ions outside the electric field shield unit, a third power supply unit that applies a voltage to the electrode of the third ion collector, and the measurement object storage Internal A gas transport unit that sends the gas to the first ion collector, and returns the gas sent to the first ion collector to the measurement object storage unit to circulate the gas; and the first ion collector A first current measurement unit that measures the ions collected in step 1 as a current, and a current correction unit that measures the radiation dose of the measurement object from the current value measured by the first current measurement unit.

  In order to solve the above-described problem, the radiation measurement apparatus according to the present invention includes a measurement object storage unit that stores a measurement target that emits radiation together with a gas, and the measurement target storage. An ion collector that collects ions in the gas flowing out from the unit, a power supply unit that applies a voltage to the electrode of the ion collector, and the gas in the measurement object storage unit is sent to the ion collector, A gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit, and a gas spraying unit that blows the gas against the surface of the measurement object including the radiation source A current measurement unit that measures the ions collected by the ion collection unit as a current, and a current correction unit that measures the radiation dose of the measurement object from the current value measured by the current measurement unit. To.

  In order to solve the above-described problem, the radiation measuring apparatus according to the present invention includes, as described in claim 24, a measuring object storage unit that stores a measuring object that emits radiation together with a gas, and the measuring object storage An ion collector that collects ions in the gas flowing out from the unit, a power supply unit that applies a voltage to the electrode of the ion collector, and the gas in the measurement object storage unit is sent to the ion collector, A gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit, an airflow stirring unit that stirs the airflow around the surface including the radiation source of the measurement object; A current measuring unit that measures the ions collected by the ion collecting unit as a current; and a current correcting unit that measures a radiation dose of the measurement object from a current value measured by the current measuring unit.

  In order to solve the above-described problem, the radiation measurement apparatus according to the present invention includes a measurement object storage unit that stores a measurement target that emits radiation together with a gas, and the measurement target storage. A first ion collector that collects ions in the gas flowing out from the unit, a first power supply that applies a voltage to the electrode of the first ion collector, and the downstream side of the first ion collector, A fourth ion collector that collects ions in the gas, a fourth power source that applies a voltage to the electrodes of the fourth ion collector, and the gas in the measurement object storage unit is sent to the ion collector. The gas sent to the ion collection unit is returned to the measurement object storage unit, and the gas is circulated, while the gas transport unit that reverses the circulation of the gas, and the ions collected by the first ion collection unit. As the current Having a first current measuring unit for measuring, and the current correction unit that measures the radiation amount of the measurement object from the current value measured by the first current measuring unit.

  In order to solve the above-described problem, the radiation measurement method according to the present invention accommodates a measurement object that emits radiation in a measurement object accommodation unit together with a gas, and accommodates the measurement object. The gas sent from the part to the ion collecting part is returned from the ion collecting part to the measurement object accommodating part to form a circulation flow path, and ions in the gas collected by the ion collecting part are used as current. In the radiation measurement method for measuring the radiation dose of the measurement object by measuring, the sensitivity correction coefficient corresponding to the shape of the measurement object is based on the sensitivity correction coefficient corresponding to the shape of the measurement object. A shape / correction coefficient acquisition step for acquiring a shape / correction coefficient, and a charge removal for neutralizing the measurement object when the measurement object is charged or the charge amount of the measurement object is equal to or greater than a threshold value When the measurement object is charged, a charge amount / correction coefficient acquisition step of acquiring a charge amount / correction coefficient that is a sensitivity correction coefficient corresponding to the charge amount of the measurement object; A temperature / humidity / correction coefficient acquisition step of acquiring a temperature / humidity / correction coefficient, which is a sensitivity correction coefficient corresponding to at least one of temperature and humidity, and injecting air having a lower humidity than the gas to replace the gas A gas replacement step, an injection ratio / correction coefficient acquisition step for acquiring an injection ratio / correction coefficient, which is a sensitivity correction coefficient corresponding to the air ratio, and a current value measured according to the rotation angle of the measurement object. When the variation is less than the threshold value, the shape / correction coefficient appropriateness determining step for determining that the shape / correction coefficient is appropriate; and when the shape / correction coefficient is determined appropriate, the current value is determined as the shape / correction coefficient. Correction factor The charge / correction coefficients, wherein to correct the temperature and humidity / correction factor and said injection rate / correction factor, to measure the radiation amount of the measurement object.

  According to the radiation measuring apparatus and the radiation measuring method according to the present invention, the radiation dose of the measurement object can be measured accurately, accurately, and efficiently.

  Embodiments of a radiation measuring apparatus and a radiation measuring method according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing a first embodiment of a radiation measuring apparatus according to the present invention.

  FIG. 1 shows a radiation measuring apparatus 10 that performs indirect measurement on ions having a relatively long lifetime ionized by radiation. The radiation measurement apparatus 10 includes a measurement object storage unit 11 that stores therein a measurement object P such as waste (pipe) that emits radiation together with a gas such as argon, helium, or air, and the measurement object. A first ion collector 15 that collects (detects) ions in the gas flowing out from the unit 11, and a first high-voltage power supply device as a power source that applies a voltage to the electrode (sensor) Sa of the first ion collector 15 17 and the gas transport in which the gas in the measurement object storage unit 11 is sent to the first ion collection unit 15 and the gas sent to the first ion collection unit 15 is returned to the measurement object storage unit 11 to circulate the gas. A fan 20 (20a, 20b) as a unit, a first current measuring unit 21 such as an electrometer that measures ions collected by the first ion collecting unit 15 as a current, and a measurement by the first current measuring unit 21 And a current correcting section 22 for correcting the current value. The current correction unit 22 has a function of measuring the radiation dose of the measurement object P from the current value. The radiation measuring apparatus 10 will be described as having two fans as gas transporting portions, but is not limited to two.

  In addition, the radiation measuring apparatus 10 is connected to the gas inflow side of the measurement target container 11 and has a gas inflow part 23 for flowing gas into the measurement target container, and a gas outflow side of the measurement target container 11. A gas collection nozzle 24 as a gas outflow part that is connected and flows out the gas in the measurement object storage unit 11, and a buffer tank 25 (25 a, 25 b) provided in the gas path that has passed through the first ion collection unit 15 The gas path 32 (32a, 32b) and the entire gas purifying unit that removes the fine particles from the gas to purify the whole gas, for example, the filter 33 (33a, 33b), and the fine particles in the gas by using electric means or the like. A gas partial purification unit that collects and purifies part of the gas, for example, a gas cleaning device 34 is provided.

  Here, the sensitivity representing the output current of the first current measuring unit 21 with respect to the same radiation dose is affected by the shape (accommodating direction) of the measurement object P. Therefore, the radiation measuring apparatus 10 has a first component for correcting sensitivity according to the shape of the measurement object P.

(First component)
As a first component for the purpose of measuring the radiation dose of the measurement object P accurately and accurately, the radiation measurement apparatus 10 has a shape for acquiring a sensitivity correction coefficient corresponding to the shape of the measurement object P. / It has the correction coefficient acquisition part 38.

  Here, the shape / correction coefficient acquisition unit 38 estimates the ion amount (ion generation efficiency) of ions that ionize the measurement object P according to the shape. For example, when there is contamination due to α-radioactivity in the pipe as the measurement object P, the distance (range) of α-rays is several cm at 1 atm, and the pipe diameter is smaller than the range. For example, α rays collide with the inner wall of the pipe and consume energy, so the rate of ionizing surrounding gas decreases. That is, the amount of ions to be ionized can be estimated from the shape of the measurement object P.

  On the other hand, in the case where there is contamination in a relatively long pipe, if the ions in the pipe do not quickly go out of the pipe, the proportion of ions lost in the middle of reaching the first ion collector 15 increases. The amount of ions collected by the first ion collector 15 decreases. That is, since the ion transport efficiency varies depending on the shape of the measurement target P, and the amount of ions varies with the transport efficiency, the amount of ions ionized depending on the shape of the measurement target P can be estimated.

  FIG. 2 is a diagram illustrating an example of a change in sensitivity with respect to the pipe-shaped measurement object P as a graph.

  As shown in the graph of FIG. 2, a correspondence table in which the shape and sensitivity of the measurement object P are associated with each other is recorded in a storage device (not shown) that is built in the radiation measurement apparatus 10 or connected externally. Keep it. The shape / correction coefficient acquisition unit 38 illustrated in FIG. 1 acquires a sensitivity correction coefficient corresponding to the shape of the measurement object P input by the operator based on the correspondence table.

  Further, for example, correspondence between the combination of ion collection efficiency and ionization space (radiation source efficiency) determined by the shape and sensitivity correction coefficient in a storage device (not shown) built in the radiation measurement apparatus 10 or externally connected. The table is stored in advance, and the shape / correction coefficient acquisition unit 38 acquires a sensitivity correction coefficient corresponding to the shape of the measurement object P input by the operator based on the correspondence table.

  FIG. 3 is a diagram showing an example of a correspondence table between combinations of ion collection efficiency and ionization space (source efficiency) and sensitivity correction coefficients.

  As shown in FIG. 3, the measurement object P is divided into several types according to the combination of ion collection efficiency and ionization space (source efficiency). Here, the measurement object P is divided into four types (types A, B, C, and D) according to the combination of ion collection efficiency and ionization space (source efficiency), and a sensitivity correction coefficient is set for each type. It is. Here, the ionization space refers to a space where α rays can be ionized.

  In addition, when the radiation measuring apparatus 10 shown in FIG. 1 has the first component, the radiation measuring apparatus 10 is provided in the measuring object storage unit 11 and rotates to rotate the mounted measuring object P. You may have the table 39 and the rotation control part 40 which controls rotation of this turntable 39. FIG. In that case, the first current measurement unit 21 measures a current according to the rotation angle of the measurement object P. Next, the current correction unit 22 corrects the current corresponding to the rotation angle with the correction coefficient acquired by the shape / correction coefficient acquisition unit 38, and corrects the sensitivity based on the variation of the corrected current value due to the rotation angle. The operator is notified of whether the coefficient, that is, the shape of the measurement object P input by the operator is appropriate. Therefore, the operator can determine whether or not the shape of the input measurement object is appropriate.

  FIG. 4 is a graph showing an example of a change in current with respect to the rotation angle of the pipe-shaped measurement object P. As shown in FIG.

  When there is contamination in the pipe, the current measured greatly depends on the rotation angle of the pipe as in the graph shown in FIG. That is, it can be determined that an ion current that changes due to rotation changes the amount of ionized ions depending on the shape. When the fluctuation of the current measured in accordance with the rotation of the turntable 39 is large, it can be determined that the sensitivity of the measured ion amount changes depending on the shape. Therefore, the current correction unit 22 corrects the current value measured by the first current measurement unit 21 with the correction coefficient acquired by the shape / correction coefficient acquisition unit 38, and the variation due to the rotation angle of the corrected current value is less than the threshold value. It is determined whether or not the shape of the measurement object P input by the operator is appropriate.

  In addition, instead of the rotary table 39 and the rotation control unit 40 shown in FIG. 1, the measurement object P in the measurement object container 11 is rotated around the measurement object P, and gas is supplied to the measurement object P from various directions. You may have the gas spraying part (not shown) to spray, and the rotation control part which controls rotation of the gas spraying part. In that case, the 1st electric current measurement part 21 measures the electric current according to the spraying direction. Next, the current correction unit 22 corrects the current value according to the spraying direction with the correction coefficient acquired by the shape / correction coefficient acquisition unit 38, and based on the variation due to the rotation angle of the corrected current value, The operator is notified whether the correction coefficient, that is, the shape of the measurement object P input by the operator is appropriate.

  Thus, when the radiation measuring apparatus 10 includes the shape / correction coefficient acquisition unit 38 as the first component, the current value measured by the current correction unit 22 by the first current measurement unit 21 is acquired as the shape / correction coefficient. By correcting with the correction coefficient output from the unit 38, the radiation dose of the measurement object P can be measured accurately and accurately.

(Second component)
As a second component for the purpose of measuring the radiation dose of the measurement object P accurately and accurately, the radiation measurement apparatus 10 includes a charged state of the measurement object P, that is, a charge of the measurement object P. The charge of the measurement object P affects the sensitivity by the presence / absence of the charge state determination unit 42 that determines whether or not the measurement object P is charged to a threshold value or less, and the current decrease rate of the reference contamination source or ion source And a charge amount / correction coefficient acquisition unit 43 that acquires a correction coefficient of sensitivity corresponding to the charge amount of the measurement object P. For example, correspondence between several charge amounts and sensitivity correction coefficients obtained by measuring in advance the sensitivity corresponding to several charge amounts in a storage device built in the radiation measuring apparatus 10 or externally connected. The table is stored in advance, and the charge amount / correction coefficient acquisition unit 43 acquires the correction coefficient based on the correspondence table.

  When radon emits alpha rays and decays into a daughter nuclide (a radionuclide that decays with radiation and a newly born nuclide has radioactivity), the alpha ray has a positive charge, so the daughter nuclide is generally It is negatively charged and adheres to the surrounding dust (or aerosol), and charged dust is generated and measured as ions. Therefore, the charge amount / correction coefficient acquisition unit 43 corrects the charged dust component.

  In addition, when the radiation measurement apparatus 10 includes the second component, the radiation measurement apparatus 10 includes a potential measurement unit 44 that measures the charge amount of the measurement object P, for example, a surface potential that measures the surface potential of the measurement object P. A total of 44a may be provided.

  The charged state determination unit 42 determines whether or not the measurement object P is charged or whether the charge amount of the measurement object P is greater than or less than a threshold value based on the direct measurement result by the surface potential meter 44a or the like. Further, the charged state determination unit 42 may determine whether or not the measurement object P is charged from the material of the measurement object P or whether the charge amount of the measurement object P is greater than or less than a threshold value. Furthermore, the current value measured before the measurement object P is accommodated in the measurement object accommodation unit 11 is recorded, and the charging state determination unit 42 is determined by the decreasing rate of the current measured after the measurement object P is accommodated. It may be determined whether the measurement object P is charged or not or whether the charge amount of the measurement object P is greater than or less than a threshold value.

  When it is determined by the charged state determination unit 42 that the measurement object P is a charged substance, or when it is determined that the measurement object P is charged based on a direct measurement result, for example, a display device A display is made (not shown) to provide the operator that the measurement object P needs to be neutralized. When it is provided that the measurement object P needs to be neutralized, the user performs a general neutralization spray or cleaning of the measurement object P with water before radiation measurement. After the surface potential of the measurement object P becomes 0 V (zero volt) or after the surface potential becomes less than the threshold value, the measurement object P is accommodated in the measurement object accommodation unit 11 to perform radiation measurement.

  Further, even when the charged state determining unit 42 is not provided or the charged state determining unit 42 is provided, a net-like conductive sheet or a thin-film conductive sheet is wound around the surface of the measurement object P in advance, and the net-like Measurement may be performed after the conductive sheet is set to 0V.

  FIG. 5 is a cross-sectional view illustrating a configuration example of a conductive sheet wound around the inner surface of the measurement target P.

  A mesh-like conductive sheet 45 is wound so as to cover the inner wall of the pipe that is the measurement object P shown in FIG. 5, and the mesh-like conductive sheet 45 is connected to the ground portion 46. In this configuration, radiation from the radioactivity attached to the inner wall of the pipe, for example, α rays, jumps into the mesh-like conductive sheet 45 from the gaps in the mesh. Therefore, even if the measurement object P is charged, the inner wall of the pipe is shielded by the net-like conductive sheet 45, so that ions ionized inside the pipe can be quickly taken out of the pipe by the gas flowing inside the pipe. It becomes.

  As described above, when the radiation measuring apparatus 10 shown in FIG. 1 includes the charge state determination unit 42 and the charge amount / correction coefficient acquisition unit 43 as the second component, the current correction unit 22 is the first current measurement unit 21. By correcting the current value measured in step 1 with the correction coefficient output from the charge amount / correction coefficient acquisition unit 43, the radiation dose of the measurement object P can be measured accurately and accurately.

(Third component)
As a third component for the purpose of accurately and efficiently measuring the radiation dose of the measurement object P, the radiation measurement device 10 includes at least one of the temperature and humidity of the gas in the circulation channel. A temperature / humidity control unit 47 that controls one side, and a temperature / humidity / correction coefficient acquisition unit 48 that acquires a sensitivity correction coefficient corresponding to the temperature of the gas in the circulation channel and a sensitivity correction coefficient corresponding to the humidity. . For example, a correspondence table between the temperature of the gas in the circulation flow path and the correction coefficient of sensitivity is stored in advance in a storage device (not shown) built in the radiation measurement apparatus 10 or connected externally, and temperature / humidity / correction The coefficient acquisition unit 48 acquires the correction coefficient of the measurement object P based on the correspondence table. Further, for example, a correspondence table between the humidity of the gas in the circulation flow path and the correction coefficient of sensitivity is stored in advance in a storage device (not shown) built in the radiation measuring apparatus 10 or connected externally, and the temperature and humidity / The correction coefficient acquisition unit 48 acquires the correction coefficient of the measurement object P based on the correspondence table. In FIG. 1, the temperature / humidity control unit 47 is provided in the buffer tank 25b. However, the temperature / humidity control unit 47 may be provided anywhere in the gas circulation channel.

  When the gas in the circulation channel is low in humidity, the charge amount in the gas may increase due to friction between the gas and the structural material, etc. Therefore, the temperature / humidity control unit 47 may control the BG (Back Ground) Set the temperature and humidity conditions for the gas with the least amount of ions. Examples of BG ions include cosmic ray-contributing ions ionized by cosmic rays and radon-contributing ions ionized by α rays emitted from radon and its daughter nuclide suspended in the gas.

  FIG. 6 is a graph showing the relationship between the temperature or humidity in the gas and the ion detection lower limit (Bq).

  The plot at 32 ° C. in FIG. 6 (a) shows the average of the lower detection limits when the gas temperature is 32 ° C. and the humidity of the gas and the radon concentration in the gas are changed. The plot at 34 ° C. shows the average of the lower detection limit when the gas temperature is 34 ° C. and the humidity of the gas and the radon concentration in the gas are changed. From this graph, it can be seen that 32 ° C., where the gas temperature is relatively low, is superior in ion detection lower limit than 34 ° C.

  Further, the plot at 40% in FIG. 6B shows the average of the detection lower limit when the gas humidity is 40% and the gas temperature and the radon concentration in the gas are changed. On the other hand, the plot at 70% shows the average of the lower limit of detection when the gas humidity is 70% and the gas temperature and the radon concentration in the gas are changed. From this graph, it can be seen that 40% where the humidity of the gas is relatively low has a lower detection limit of ions than 70%.

  As described above, when the radiation measurement apparatus 10 includes the temperature / humidity control unit 47 and the temperature / humidity / correction coefficient acquisition unit 48 as the third component and controls the temperature and humidity of the gas relatively low, the current correction unit 22 corrects the current value measured by the first current measurement unit 21 with the correction coefficient output from the temperature / humidity / correction coefficient acquisition unit 48, so that the radiation dose of the measurement target P can be accurately and efficiently determined. It can be measured.

  In addition, in the gas in the measurement target container 11 that stores the measurement target P, BG ions are included in addition to the measurement target ions (measurement target ions) ionized according to the radiation dose attached to the measurement target P. Exists.

  These ions are collected by the first ion collecting unit 15 and measured as a current by the first current measuring unit 21, and the measured current includes a BG current caused by BG ions. Therefore, the BG current is measured before the measurement object P is accommodated in the measurement object accommodating portion 11, and the data processing for subtracting the BG current from the measurement current is performed. The current to be measured (current to be measured) is acquired.

  However, if the BG current is measured each time before the first current measurement unit 21 measures the current, it is necessary to perform ion collection / current measurement twice in one radiation measurement. Therefore, in general, data processing is performed in which a BG current is measured once at a certain timing, the BG current value is used as a representative value, and then the representative value is subtracted from each current value measured by the first current measuring unit 21. To do. Note that the BG current value as a representative value is updated regularly or irregularly.

  When the representative value of the BG current value is used, in order to accurately and accurately measure the radiation dose of the measurement object P, the radiation measurement apparatus 10 uses a BG current value that is different from each current value as a representative value. It has the 7th component mentioned later which checks whether it exists suitably.

  In addition, the BG current value that is different from each current value needs to be appropriate as a representative value, but when the gas contains a relatively large amount of BG ions, the fluctuation of the BG current due to the BG ions may occur. It becomes large and the influence on the measurement performed by the first current measuring unit 21 becomes large. Therefore, in order for the BG current value that is different from each current value to be appropriate as a representative value, the relationship between the measurement target current and the BG current in the measurement current is such that the smaller the BG current is, the smaller the measurement target current is. Good. That is, when the measurement is performed by the first current measuring unit 21, it is desirable that the amount of BG ions in the gas is small. Therefore, the radiation measuring apparatus 10 includes fourth to seventh components that reduce BG ions in the gas.

(Fourth component)
As a fourth component for the purpose of accurately and efficiently measuring the radiation dose of the measurement object P, the radiation measuring apparatus 10 has a radioactive gas collection device for collecting radioactive gas in the gas. Part, for example, activated carbon 51. In FIG. 1, the activated carbon 51 is provided in the buffer tank 25b, but the activated carbon 51 may be provided anywhere in the gas circulation channel. Further, the radioactive gas collection unit may be an electric field collection unit that collects an electric field.

  The activated carbon 51 collects radon in the gas in the circulation flow path and reduces radon-contributing ions as BG ions. On the other hand, the activated carbon 51 can adsorb radon generated by the destruction of uranium or the like attached to the measurement object P, and has a function of preventing the accumulation of radon in the measurement object storage unit 11 during measurement. Yes.

  As described above, when the radiation measuring apparatus 10 includes the activated carbon 51 as the fourth component, based on the current value measured by the first current measuring unit 21, the measurement object P is accurately and accurately. Can measure radiation dose.

(Fifth component)
As a fifth component for the purpose of accurately and efficiently measuring the radiation dose of the measurement object P, the radiation measuring device 10 has an equivalent temperature compared to the gas in the circulation channel. A gas replacement unit 53 for injecting low-humidity air (dry air) into the measurement object storage unit 11 to replace the gas in the circulation channel, and a circulating flow of air injected from the gas replacement unit 53 An injection ratio / correction coefficient acquisition unit 54 that acquires a correction coefficient of sensitivity corresponding to the ratio in the road. For example, a correspondence table between the ratio of the injected air in the circulation flow path and the correction coefficient of sensitivity is stored in advance in a storage device (not shown) built in the radiation measuring apparatus 10 or externally connected, and injected. The ratio / correction coefficient acquisition unit 54 acquires the correction coefficient of the measurement object P based on the correspondence table. In addition, in FIG. 1, although it has the gas replacement part 53 so that the air from the gas replacement part 53 may be inject | poured into the inside of the measurement object accommodating part 11, the gas replacement part 53 is in a gas circulation flow path. You may have it anywhere.

  FIG. 7 is a graph showing the time-series transition of the temperature, humidity, and BG current value of the air in the circulation flow path.

  According to this graph, from time 18:05 to 19:00, the ratio of the replaced air in the circulation flow path is 50% from the gas replacement unit 53 to the inside of the measurement object storage unit 11. The dry air is injected at the same temperature as the gas. From time 18:05 to 19:00, the temperature of the gas in the circulation channel is maintained at about 29 ° C., the humidity is reduced by about 9% (17% → 8%), and the BG current value is about It is reduced by 100 fA (680 fA → 580 fA). From this graph, it can be seen that the relatively low humidity of the gas is excellent in reducing the BG current.

  As described above, when the radiation measuring apparatus 10 includes the gas replacement unit 53 and the injection ratio / correction coefficient acquisition unit 54 as the fifth component and increases the ratio of the injected air in the circulation flow path, The correction unit 22 corrects the current value measured by the first current measurement unit 21 with the correction coefficient output from the injection ratio / correction coefficient acquisition unit 54, so that the radiation of the measurement object P can be accurately and efficiently performed. The amount can be measured.

(Sixth component)
As a sixth component for the purpose of accurately and efficiently measuring the radiation dose of the measurement object P, the radiation measuring apparatus 10 includes a first ion collector 15 in the gas before collecting ions. And a second high-voltage power supply device 56 as a power supply unit that applies a voltage to the electrode Sb of the second ion collection unit 55.

  When radon emits alpha rays and disintegrates into daughter nuclides, the alpha radii have a positive charge, so the daughter nuclides are generally negatively charged and adhere to the surrounding dust, producing charged dust as ions. It is measured. Therefore, the daughter nuclides charged after the radon decays are collected in advance by the second ion collector 55, thereby reducing BG ions in the gas when the ions are collected by the first ion collector 15. That is, the first high-voltage power supply device 17 for the first ion collection unit 15 is activated after the power supply of the second high-voltage power supply device 56 for the second ion collection unit 55 is set to a predetermined voltage. The attachment of the daughter nuclide to the ion collector 15 can be suppressed.

  As described above, when the radiation measuring apparatus 10 includes the second ion collecting unit 55 and the second high-voltage power supply device 56 as the sixth component, the radiation measuring apparatus 10 is accurately based on the current value measured by the first current measuring unit 21. The radiation dose of the measurement object P can be measured accurately and efficiently.

(Seventh component)
As a seventh component for the purpose of accurately and efficiently measuring the radiation dose of the measurement object P, the radiation measurement apparatus 10 includes a second ion collector before the measurement object P is accommodated. The second current measurement unit 57 such as an electrometer that measures the BG ions collected in 55 as the BG current, and the fluctuation of the BG current is evaluated based on the output of the second current measurement unit 57, and an appropriate BG is determined by the evaluation. And a BG current evaluation unit 58 that provides a current to the current correction unit 22.

  Thus, when the radiation measurement apparatus 10 includes the second current measurement unit 57 and the BG current evaluation unit 58 as the seventh component, the current correction unit 22 determines the current value measured by the first current measurement unit 21. By correcting with the current value output from the BG current evaluation unit 58, the radiation dose of the measurement object P can be measured accurately and accurately.

  In order to achieve the purpose of measuring the radiation dose of the measurement object P accurately and accurately, the radiation measurement apparatus 10 has at least one of the first to sixth components. do it. Moreover, when it has a 6th component, you may have a 7th component. However, in order to achieve the above-described object, it is preferable to have all of the first to seventh components like the radiation measuring apparatus 10 shown in FIG. A case where all of the first to seventh components are included in FIG.

  That is, the radiation measuring apparatus 10 uses the fans 20a and 20b to move the gas in the measurement object storage unit 11 from the gas collection nozzle 24 to the gas path 32a, the first ion collection unit 15, the buffer tank 25a, the fan 20a, the filter 33a, A gas circulation channel that returns to the measurement object storage unit 11 again through the gas path 32b, the buffer tank 25b, the fan 20b, the second ion collection unit 55, the gas inflow unit 23, and the filter 33b in this order is formed.

  Further, a CPU (Central Processing Unit, not shown) executes a program built in a storage device (not shown), whereby the first current measurement unit 21, the current correction unit 22, the shape / correction coefficient acquisition unit 38, and rotation control. Unit 40, charged substance determination unit 42, charge amount / correction coefficient acquisition unit 43, temperature / humidity control unit 47, temperature / humidity / correction coefficient acquisition unit 48, injection ratio / correction coefficient acquisition unit 54, second current measurement unit 57 and BG Although it functions as the current evaluation unit 58, all or part of each component may be a specific circuit. Further, the first ion collection unit 15, the first high-voltage power supply device 17, the fans 20a and 20b, the gas cleaning device 34, the gas replacement unit 53, the second ion collection unit 55, and the second high-voltage power supply device 56 are operated by the CPU. It may be controlled.

  Next, the radiation measurement method according to the present invention will be described with reference to the flowchart shown in FIG. In addition, the code | symbol which attached | subjected the number to "S" in a figure shows each step of a flowchart.

  First, when the shape of the measurement object P selected by the operator is input to the radiation measurement apparatus 10, the shape / correction coefficient acquisition unit 38 as a first component included in the radiation measurement apparatus 10 functions (step S1). ). The shape / correction coefficient acquisition unit 38 acquires a sensitivity correction coefficient corresponding to the shape of the measurement object P from the correspondence table shown in FIG.

  In addition, the charge state determination unit 42 and the charge amount / correction coefficient acquisition unit 43 as the second component included in the radiation measurement apparatus 10 function (step S2). Based on the surface potential measured by the surface potential meter 44a, the charged state determination unit 42 determines whether or not the measurement object P is charged (step S2-1). When the determination in step S2-1 is Yes, that is, when it is determined that the measurement object P is charged, the charged state determination unit 42 determines whether or not the charge amount of the measurement object P is equal to or greater than a threshold value. Judgment is made (step S2-2). If the determination in step S2-2 is Yes, that is, if it is determined that the charge amount of the measurement object P is greater than or equal to the threshold value, the measurement object P is neutralized (step S2-3), and the charged state determination unit 42 again determines whether or not the measurement object P is charged (step S2-1). The measurement object P is neutralized by washing the measurement object P with a general neutralization unit, for example, a neutralization spray or a water spray. Further, instead of static elimination, as shown in FIG. 5, a net-like conductive sheet or a thin-film conductive sheet is wound around the surface of the measurement object P, and the net-like conductive sheet is set to 0 V or less than a threshold value before radiation measurement. You may do it.

  On the other hand, if it is determined No in step S2-1, that is, if the measurement object P is not charged, the process proceeds to step S3. Further, when the determination in step S2-2 is No, that is, when the charge amount of the measurement object P is determined to be less than the threshold value, the charge amount / correction coefficient acquisition unit 43 corresponds to the charge amount of the measurement object P. A sensitivity correction coefficient is acquired (step S2-4), and the process proceeds to step S3.

  In addition, the gas in the measurement object storage unit 11 of the radiation measurement apparatus 10 is stored and the fans 20a and 20b are operated, so that the gas in the measurement target storage unit 11 is transferred from the gas collection nozzle 24 to the gas path. 32a, the first ion collector 15, the buffer tank 25a, the fan 20a, the filter 33a, the gas path 32b, the buffer tank 25b, the fan 20b, the second ion collector 55, the gas inflow portion 23, and the filter 33b in order. Return to the object storage unit 11. Here, the filters 33a and 33b and the gas cleaning device 34 function. The radiation measuring device 10 uses the filters 33a and 33b for purifying the entire circulating gas and the gas purifier 34 for sampling and purifying a part of the gas to ensure that the circulating gas has a certain cleanliness while ensuring the amount of the circulating gas. Let it be maintained.

  Furthermore, the temperature / humidity control unit 47 and the temperature / humidity / correction coefficient acquisition unit 48 as the third component of the radiation measuring apparatus 10 function (step S3). The temperature / humidity controller 47 maintains the gas and humidity in the circulation channel under conditions excellent in the ion detection lower limit. Further, the temperature / humidity / correction coefficient acquisition unit 48 acquires sensitivity correction coefficients corresponding to the gas and humidity in the circulation channel.

  Further, the activated carbon 51 as the fourth component included in the radiation measuring apparatus 10 functions (step S4). The activated carbon 51 collects radon in the gas in the circulation flow path and reduces radon-contributing ions as BG ions. On the other hand, the activated carbon 51 also adsorbs radon produced by the destruction of uranium or the like attached to the measurement object P after the measurement object P is accommodated.

  In addition, the gas replacement unit 53 and the injection ratio / correction coefficient acquisition unit 54 as the fifth component included in the radiation measurement apparatus 10 function (step S5). The gas replacement unit 53 injects air (dry air) having a lower humidity than the gas into the measurement object storage unit 11 to replace the gas. Further, the injection ratio / correction coefficient acquisition unit 54 acquires a sensitivity correction coefficient corresponding to the ratio of the replaced air.

  Subsequently, after a lapse of a required time from the operation of step S5, the second ion collector 55 as a sixth component included in the radiation measurement apparatus 10 in the stationary state of the first high-voltage power supply device 17 for the first ion collector 15. And the 2nd high voltage power supply device 56 functions, and starts the 2nd high voltage power supply device 56 for the 2nd ion collection part 55 (step S6). The second ion collector 55 collects ions in the gas. In this ion collection process, a voltage is applied to the electrode Sb of the second ion collector 55 by the second high-voltage power supply device 56, and the second ion collector 55 uses the ions in the gas sent from the fan 20b as BG ions. Collect by electric field.

  Next, the measurement target P such as a pipe is placed on the rotary table 39 in the measurement target storage unit 11 of the radiation measurement apparatus 10, and the measurement target P is stored inside the measurement target storage unit 11 (step). S7).

  After the second high-voltage power supply device 56 for the second ion collector 55 is set to a predetermined voltage, the first high-voltage power supply device 17 for the first ion collector 15 is activated (step S8), thereby The ion collector 15 collects ions. In this ion collection process, a voltage is applied to the electrode Sa of the first ion collection unit 15 by the first high-voltage power supply device 17, and the first ion collection unit 15 applies ions in the gas sent from the gas collection nozzle 24 to the electric field. Collect by. In the gas, BG ions exist in addition to the measurement target ions. Therefore, the ions to be collected by the first ion collecting unit 15 include measurement target ions and BG ions. However, as described above, when the radiation measurement apparatus 10 includes the second ion collection unit 55, BG ions in the gas are collected in advance by the second ion collection unit 55, and thus the electrode of the first ion collection unit 15 is used. The attachment of daughter nuclides to Sa is reduced.

  The first current measurement unit 21 starts measurement as a current of ions collected by the first ion collection unit 15 (step S9).

  During the current measurement, the shape / correction coefficient acquisition unit 38, the rotation table 39, and the rotation control unit 40 as the first component of the radiation measurement apparatus 10 function (step S10). First, the rotary table 39 on which the measurement object P is placed is rotated by a drive signal generated from the rotation control unit 40 (step S10-1). The current correction unit 22 corrects the current value measured by the first current measurement unit 21 with the correction coefficient acquired in step S1 (or re-acquired in step S10-4), and depends on the corrected current rotation angle. It is determined whether or not the fluctuation is greater than or equal to a threshold value (step S10-2).

  If it is determined in step S10-2 that Yes, i.e., the variation due to the rotation angle of the corrected current value is greater than or equal to the threshold value, the operator is informed that the shape of the measurement object P input by the operator is not appropriate. Notification is made (step S10-3). The operator inputs the shape of the measurement object P, re-acquires a sensitivity correction coefficient corresponding to the shape of the measurement object P from the correspondence table shown in FIG. 2 or 3 (step S10-4), It returns to step S10-1.

  On the other hand, if it is determined in step S10-2 that the variation due to the rotation angle of the corrected current value is less than the threshold value, a sensitivity correction coefficient corresponding to the shape of the measurement object P is determined. (Step S10-5).

  Therefore, when the rotary table 39 shown in FIG. 1 is provided, the shape / correction coefficient acquisition unit 38 can confirm whether or not the shape manually input by the operator in step S1 is appropriate. If the manually input shape is different from the shape stored in advance in the correspondence table with respect to the rotation angle, the appropriate shape can be input again to correct the sensitivity correction coefficient.

Next, the second current measuring unit 57 and the BG current evaluating unit 58 as the seventh component included in the radiation measuring apparatus 10 function (step S11). First, the 2nd electric current measurement part 57 measures the ion collected after the measurement target P was accommodated in the 2nd ion collection part 55 as an electric current (step S11-1). The BG current evaluation unit 58 evaluates the BG current based on the output of the second current measurement unit 57 (step S11-2). Here, most of the measurement target ions ionized in the measurement target container 11 after the measurement target P is stored are collected by the first ion collector 15 connected immediately after the measurement target container 11. Is done. On the other hand, the remaining BG ions ionized between the first ion collector 15 and the second ion collector 55 are collected by the second ion collector 55. Therefore, it can be assumed that the BG ions collected by the second ion collector 55 are a constant amount per unit volume. That is, the volume of the gas collected by the first ion collector 15 and the volume of the gas collected by the second ion collector 55 are known, and are caused by BG ions contained in the ions collected by the first ion collector 15. The BG current value to be

  The BG current evaluation unit 58 monitors the fluctuation of the predicted BG current value calculated by the above formula in time series. When the fluctuation of the predicted BG current is smaller than a preset threshold value, the predicted BG current value is provided to the current correction unit 22 as the BG current value. On the other hand, when it is determined that the fluctuation of the predicted BG current is large, such as when the fluctuation of the predicted BG current is larger than a preset threshold value, the BG current evaluation unit 58 corrects the BG current value measured and evaluated in advance. Part 22 is provided.

  The current correction unit 22 corrects the current value measured after step S9 with the correction coefficient acquired in steps S1, S2, S3, and S5 and the BG current output from the BG current evaluation unit 58 evaluated in step S11. Then, the radiation dose of the measurement object P is measured (step S12).

  Note that the order of steps S1 to S5 and the order of steps S10 and S11 are not limited, and may be performed in parallel.

  FIG. 9 is a flowchart showing a first modification of the radiation measurement method according to the present invention.

  First, in the case where the fans 20a and 20b are operated after placing the measurement object P such as a pipe in the measurement object storage unit 11 of the radiation measurement apparatus 10 in step S7 (or before storage). The fans 20a and 20b are stopped, and the gas circulation is stopped (step S21). After the second high-voltage power supply device 56 for the second ion collector 55 is set to a predetermined voltage, the first high-voltage power supply device 17 for the first ion collector 15 is activated (step S8), thereby The ion collector 15 collects ions. In this ion collection process, a voltage is applied to the electrode Sa of the first ion collection unit 15 by the first high-voltage power supply device 17, and the first ion collection unit 15 applies ions in the gas sent from the gas collection nozzle 24 to the electric field. Collect by.

  The first current measurement unit 21 starts measurement as a current of ions collected by the first ion collection unit 15 (step S9). The first current measurement unit 21 counts output pulses (step S22).

  When the output pulse of the first current measuring unit 21 is monitored in time series, a pulsed current change as shown in FIG. 10 can be observed. This pulse is considered to be an ionization pulse due to α rays generated when radon collapses in the vicinity of the first ion collector 15, and by counting this output pulse, the output pulse is converted into the number of BG ions per unit volume. Yes (step S23). That is, the first current measurement unit 21 can convert the output pulses counted by the first current measurement unit 21 into a BG current (step S24).

  The current correction unit 22 measures the radiation dose of the measurement object P based on the current value measured after step S9 and the BG current value converted in step S24 (step S12).

  FIG. 11 is a flowchart showing a second modification of the operation of the radiation measuring apparatus 10 according to the present invention.

  FIG. 11 shows a second modification of the radiation measurement method when the radiation measurement apparatus 10 includes the second current measurement unit 57 and the BG current evaluation unit 58 as sixth components.

  In the present modification, assuming that the volume in the measurement object storage unit 11 decreases by the volume of the measurement object P, the volume in the measurement object storage unit 11 is subtracted from the volume of the measurement object P. The BG current value is calculated according to the difference.

  First, in step S7, a measurement object P such as a pipe is accommodated in the measurement object accommodation part 11 of the radiation measurement apparatus 10. The second high-voltage power supply device 56 for the second ion collector 55 is activated (step S6). In addition, by starting the first high-voltage power supply device 17 for the first ion collector 15 (step S8), the first current measurement unit 21 performs measurement as the current of ions collected by the first ion collector 15. Start (step S9).

  The 2nd electric current measurement part 57 measures the ion collected after the measurement target P was accommodated in the 2nd ion collection part 55 as an electric current (step S11-1). The BG current evaluation unit 58 calculates a BG current value corresponding to the difference between the BG current values based on the volume of the measurement object P and the volume in the measurement object storage unit 11 (step S11-3). Therefore, underestimation of the radiation dose can be avoided. In addition, as a relationship of the BG current value with respect to the volume in the measurement object storage unit 11, a value obtained from a relationship obtained by measurement in advance as shown in FIG. 12 may be used.

  The current correction unit 22 measures the radiation dose of the measurement object P based on the current value measured after step S9 and the BG current value calculated in step S11-3 (step S12).

  According to the radiation measuring apparatus 10 and the radiation measuring method shown in FIG. 1, by having the first component, that is, the shape / correction coefficient acquisition unit 38, the sensitivity change due to the shape of the measurement object P is appropriately corrected. In addition, since the validity of the shape of the measurement object P input by the operator during the measurement of the radiation dose of the measurement object P can be evaluated and the sensitivity correction coefficient can be corrected, the accuracy of the measurement object P can be accurately measured. The radiation dose can be measured.

  In addition, according to the radiation measuring apparatus 10 and the radiation measuring method, the second component, that is, the charge state determination unit 42 and the charge amount / correction coefficient acquisition unit 43 are included, so that it depends on the charge amount of the measurement object P. The change in sensitivity can be appropriately corrected, and the radiation dose of the measurement object P can be measured accurately and accurately.

  Furthermore, according to the radiation measuring apparatus 10 and the radiation measuring method, by having the third component, that is, the activated carbon 51, it is possible to adsorb radon generated by the uranium or the like adhering to the measurement object P being destroyed, The radiation dose of the measurement object P can be measured accurately and accurately.

  In addition, according to the radiation measurement apparatus 10 and the radiation measurement method, the fourth component, that is, the temperature / humidity control unit 47 and the temperature / humidity / correction coefficient acquisition unit 48, can reduce BG ions in the gas. The radiation dose of the measurement object P can be measured accurately, accurately and efficiently.

  In addition, according to the radiation measuring apparatus 10 and the radiation measuring method, the fifth component, that is, the gas replacement unit 53 and the injection ratio / correction coefficient acquisition unit 54 allows air having a lower humidity than the gas ( The BG current can be reduced by injecting dry air) into the measurement object storage unit 11, and the radiation dose of the measurement object P can be measured accurately, accurately, and efficiently.

  Furthermore, according to the radiation measuring apparatus 10 and the radiation measuring method, the daughter nuclides are attached to the first ion collector 15 by having the sixth component, that is, the second ion collector 55 and the high-voltage power supply device 56. Therefore, the radiation dose of the measurement object P can be measured accurately, accurately, and efficiently.

  In addition, according to the radiation measurement apparatus 10 and the radiation measurement method, the seventh component, that is, the second current measurement unit 57 and the BG correction coefficient evaluation unit 58 is included, so that the BG current component included in the current value The radiation dose of the measurement object P can be measured accurately, accurately, and efficiently.

  FIG. 13 is a schematic view showing a second embodiment of the radiation measuring apparatus according to the present invention.

  FIG. 13 shows the radiation measurement apparatus 10A. The radiation measurement apparatus 10A includes a measurement object storage unit 11, a first ion collection unit 15 (shown in FIG. 1), a first high-voltage power supply device 17 (shown in FIG. 1), a fan 20 (shown in FIG. 1), a first 1 has a current measurement unit 21 (shown in FIG. 1) and a current correction unit 22 (shown in FIG. 1). Further, the radiation measuring apparatus 10 includes a gas inlet 23, a gas collection nozzle 24, a buffer tank 25 (shown in FIG. 1), a gas path 32 (shown in FIG. 1), a filter 33 (shown in FIG. 1), and a gas cleaner. A device 34 (shown in FIG. 1) is provided.

  Further, the radiation measuring apparatus 10A includes a gas inflow portion 23 (shown in FIG. 1), a gas collection nozzle 24 (shown in FIG. 1), buffer tanks 25a and 25b (shown in FIG. 1), and gas paths 32a and 32b (shown in FIG. 1). 1).

  Then, as described with reference to FIG. 1, the radiation measurement apparatus 10 uses the fans 20 a and 20 b to move the gas in the measurement target container 11 from the gas collection nozzle 24 to the gas path 32 a, the first ion collection unit 15, and the buffer tank. 25a, fan 20a, filter 33a, gas path 32b, buffer tank 25b, fan 20b, second ion collection unit 55, gas inflow unit 23, and gas 33 A road shall be formed.

  Further, the radiation measuring apparatus 10 </ b> A is provided in the measurement object container 11 as an eighth component, shields the electric field, and directs ions in the measurement object container 11 to the first ion collector 15. A voltage is applied to the electrode Sc of the third ion collector 62 and the third ion collector 62 that collects ions outside the electric field shield 61. A third high-voltage power supply device 63 as a power supply unit for applying a voltage, and a grounding unit 65 for grounding the measurement object P by 0V. The operation of the third ion collector 62, the third high-voltage power supply device 63, and the ground unit 65 may be controlled by a CPU (not shown).

  FIG. 14 is a diagram schematically illustrating the operation of the radiation measuring apparatus 10A. FIG. 14 shows a case where the measurement object P is a pipe and ions on the inner surface of the pipe are measured. Therefore, the pipe itself also functions as the electric field shield part 61 for the inner surface of the pipe.

  The fans 20a and 20b and the ground unit 65 are operated, and the first high voltage power supply device 17 for the first ion collection unit 15 and the third high voltage power supply device 63 for the third ion collection unit 62 are activated. If the α-ray source R is attached to the inner surface of the pipe that is the measurement object P, the ions I are ionized on the inner surface of the pipe by the α-rays. The ions I are carried to the first ion collector 15 by the air current.

  On the other hand, BG ions ionized by cosmic rays or the like on the outer surface of the pipe are collected by the third ion collector 62. That is, when the pipe is grounded at 0 V by the grounding portion 65, the electric field on the inner surface of the pipe is weak, and the ions I are transferred to the first ion collecting unit 15 side by the airflow, but the electric field is transferred by the airflow on the outer surface of the pipe. Is adjusted by the third high-voltage power supply device 63 so as to be equal to or stronger than.

  FIG. 15 is a graph showing a breakdown of the current caused by the ions collected by the third ion collecting unit 62.

  The current caused by the ions collected by the first ion collector 15 is divided into a current caused by a signal caused by α rays and a BG current caused by a signal caused by BG such as cosmic rays. According to the graph shown in FIG. 15, when ions are measured by the first ion collecting unit 15 in a state where the third high-voltage power supply device 63 is activated and the electrode Sc is applied, the measurement is performed by the first current measuring unit 21. The BG current resulting from the signal from the BG is reduced from the measured current.

  In the present embodiment, the inner surface of the pipe has been described as an example, but if the electric field shield part 61 is separately provided around the measurement target P, the volume of the measurement target container 11 is similarly reduced. The effect of reducing the BG current is obtained.

  According to the radiation measuring apparatus 10 </ b> A and the radiation measuring method shown in FIG. 13, the eighth component, that is, the electric field shield part 61, the third ion collecting part 62, the third high-voltage power supply apparatus 63, and the ground part 65 is provided. The contribution component due to cosmic rays or the like in the current collected by the first ion collector 15 can be reduced, and the radiation dose of the measurement object P can be measured accurately and accurately.

  FIG. 16 is a schematic view showing a third embodiment of the radiation measuring apparatus according to the present invention.

  FIG. 16 shows the radiation measurement apparatus 10B. The radiation measurement apparatus 10B includes a measurement object storage unit 11, a first ion collection unit 15 (shown in FIG. 1), a first high-voltage power supply device 17 (shown in FIG. 1), a fan 20 (shown in FIG. 1), a first 1 has a current measurement unit 21 (shown in FIG. 1) and a current correction unit 22 (shown in FIG. 1). Further, the radiation measuring apparatus 10 includes a gas inlet 23, a gas collection nozzle 24, a buffer tank 25 (shown in FIG. 1), a gas path 32 (shown in FIG. 1), a filter 33 (shown in FIG. 1), and a gas cleaner. A device 34 (shown in FIG. 1) is provided.

  Then, as described with reference to FIG. 1, the radiation measuring apparatus 10 </ b> B uses the fans 20 a and 20 b to move the gas in the measurement target container 11 from the gas collection nozzle 24 to the gas path 32 a, the first ion collection unit 15, and the buffer tank. 25a, fan 20a, filter 33a, gas path 32b, buffer tank 25b, fan 20b, second ion collection unit 55, gas inflow unit 23, and gas 33 A road shall be formed.

  In addition, the radiation measuring apparatus 10 </ b> B is provided in the measurement object storage unit 11 as a ninth component, shields the electric field, and guides ions in the measurement object in the direction of the first ion collection unit 15. It has a shield part 61, a charged substance 71 (71a, 71b) provided outside the electric field shield part 61 in the measurement object accommodating part 11, and a ground part 65 for grounding the measurement object P by 0V.

  FIG. 17 is a diagram schematically illustrating the operation of the radiation measurement apparatus 10B. Note that FIG. 17 shows a case where the measurement object P is a pipe and the ions on the inner surface of the pipe are measured, so that the pipe itself also functions as the electric field shield 61 for the inner surface of the pipe.

  The fans 20a and 20b and the ground unit 65 are operated, and the first high voltage power supply device 17 for the first ion collection unit 15 and the third high voltage power supply device 63 for the third ion collection unit 62 are activated. When the α ray source R is attached to the pipe inner surface which is the measurement object P, the ions I are ionized on the pipe inner surface by the α rays, and the ions I are carried to the first ion collector 15 by the air current.

  On the other hand, BG ions ionized by cosmic rays on the outer surface of the pipe are collected by the charged substances 71a and 71b.

  In the present embodiment, the inner surface of the pipe has been described as an example, but if the electric field shield part 61 is separately provided around the measurement target P, the volume of the measurement target container 11 is similarly reduced. The effect of reducing the BG current is obtained.

  According to the radiation measuring apparatus 10 </ b> B and the radiation measuring method shown in FIG. 16, the first ion collecting unit 15 includes the ninth component, that is, the electric field shield unit 61, the charged substances 71 a and 71 b, and the ground unit 65. The contribution component due to cosmic rays or the like in the collected current can be reduced, and the radiation dose of the measurement object P can be measured accurately, accurately, and efficiently.

  FIG. 18 is a schematic view showing a fourth embodiment of the radiation measuring apparatus according to the present invention.

  FIG. 18 shows the radiation measuring apparatus 10C. The radiation measurement apparatus 10C includes a measurement object storage unit 11, a first ion collection unit 15 (shown in FIG. 1), a first high-voltage power supply device 17 (shown in FIG. 1), a fan 20 (shown in FIG. 1), a first 1 has a current measurement unit 21 (shown in FIG. 1) and a current correction unit 22 (shown in FIG. 1). Further, the radiation measuring apparatus 10 includes a gas inlet 23, a gas collection nozzle 24, a buffer tank 25 (shown in FIG. 1), a gas path 32 (shown in FIG. 1), a filter 33 (shown in FIG. 1), and a gas cleaner. A device 34 (shown in FIG. 1) is provided.

  Then, as described in FIG. 1, the radiation measuring apparatus 10 </ b> C uses the fans 20 a and 20 b to move the gas in the measurement object storage unit 11 from the gas collection nozzle 24 to the gas path 32 a, the first ion collection unit 15, and the buffer tank. 25a, fan 20a, filter 33a, gas path 32b, buffer tank 25b, fan 20b, second ion collection unit 55, gas inflow unit 23, and gas 33 A road shall be formed.

  Moreover, 10 C of radiation measuring devices have the gas spraying part 76 which blows gas with respect to the surface periphery containing the radiation generation source of the measuring object P in the measuring object accommodating part 11 as a 10th component. Therefore, in the measurement object storage unit 11, there is a difference between the gas flow velocity in the airflow acceleration region a where the airflow is accelerated by the blown gas and the gas flow velocity in the airflow non-acceleration region outside the airflow acceleration region a. The operation of the gas blowing unit 76 may be controlled by a CPU (not shown).

  The fans 20a and 20b are operated, and the first high voltage power supply device 17 for the first ion collector 15 is activated. Further, when the gas blowing unit 76 is operated, the ionized ions quickly reach the first ion collecting unit 15 by riding on the air flow in the air flow acceleration region a accelerated by the gas blowing unit 76. Here, primary ions generated by ionization of gas by charged particles such as α-rays are unstable and generate relatively stable ions (positive and negative ion pairs, secondary ions) through chemical reactions with other molecules. . This ion disappears by a recombination reaction (self-recombination reaction or recombination reaction with BG ions) until it is peeled off and transported to the first ion collector 15 (not shown). Large ionization due to adhesion to particles prevents detection.

  Here, the relationship between the ion recombination reaction and the number of ions will be described.

  FIG. 19 is a diagram for explaining the relationship between the ion recombination reaction and the number of ions.

As shown in FIG. 19, the ions (number density φ) are distributed as cylindrical columnar ions Ic along the trajectory of the charged particles immediately after the generation of the measurement object P in the radiation generation source. When the ion undergoes self-recombination reaction or recombination reaction with BG ions (number density N), the number of ions and the number of BG ions are

  The first and second terms on the right side of equations (1) and (2) are the disappearance of ions due to ion recombination reaction, the third term is the disappearance of ions due to adhesion to the aerosol, and the fourth term is the ion due to airflow. Represents the transport of In addition, the fifth term on the right side of Equation (1) represents a decrease in density due to ion diffusion, and the fifth term on the right side of Equation (2) represents generation of BG ions. For example, by substituting the number density of ions φ into the formula (1) at the required elapsed time t and converting the number of ions into current, the current that has undergone the ion recombination reaction at high density can be converted.

  FIG. 20 is a graph showing the relationship between the gas flow velocity and the current value. In addition, let the gas sprayed from the gas spraying part 76 be air, and let the radiation R be alpha rays.

FIG. 20 shows, as a graph, the relationship between various flow rates of the gas to be blown and the current value A in theoretical calculation when it is assumed that there is no recombination reaction at a high density immediately after the generation of ions. FIG. 20 shows, as a graph, the relationship between the various flow rates of the gas to be blown and the current value B when the number of ions calculated by Equation (1) is converted into current assuming that there is a recombination reaction. Show. In addition, 0.035 cm < ² > / s which is a standard value in air | atmosphere shall be used for the ion diffusion coefficient D of Formula (1). FIG. 20 shows the relationship between the various flow speeds of the gas to be blown and the current value C measured. The current values A, B, and C are shown separately when the distance between the detector (first ion collector 15) and the radiation source is 10, 60, and 110 cm.

  According to this graph, it can be seen that the number of ions decreases by about several tens by the recombination reaction of ions immediately after generation, and the current decreases by several tens. Further, the current value B calculated by the equation (1) is about 28% lower than the current value A on average, and is close to the actually measured current value C compared to the current value A. . In addition, the decreasing tendency when the flow velocity at the actually measured current value C is 1 m / s or more is due to a decrease in sensitivity of the first ion collecting unit 15, and shows the same increasing tendency as the current value A by performing sensitivity correction. .

  Next, the relationship between the gas flow rate and the number of ions will be described.

  FIG. 21 is a graph showing the relationship between the gas flow velocity and the theoretical calculation value ratio (current value B / current value A in FIG. 20) and an approximate straight line of the relationship.

  FIG. 21 shows the relationship between the flow velocity of gas and the theoretical calculation value ratio for each distance (10, 50, and 100 cm) between the detector (first ion collector 15) and the radiation generation source, and an approximate straight line of the relationship. Is shown. According to this graph, it is understood that the theoretical calculation value ratio increases as the gas velocity increases. That is, the current value B approaches the current value A as the gas flow rate increases. This is because the number effect of ions decreases as the diffusion effect increases as the gas flow rate increases, and the decrease in the number of ions due to the ion recombination effect immediately after generation is suppressed.

  In this graph, when the gas flow rate is 1 m / s or less, the theoretical calculation value ratio increases rapidly. On the other hand, when the gas flow velocity is 1 m / s or more, the theoretical calculation value ratio increases gently. The theoretical calculation value ratio becomes 1 when the expected flow velocity becomes sufficiently high. Therefore, when the gas flow velocity is 1 m / s or less, the current value fluctuates due to slight fluctuations in the gas flow velocity, and it can be said that the measurement accuracy decreases. Conversely, if the flow velocity of the gas blown from the gas sprayer 76 is at least 1 m / s or more, fluctuations in the current value can be suppressed.

  Further, when the direction of blowing the gas blown from the gas blowing unit 76 shown in FIG. 18 and the surface direction including the radiation generation source of the measurement object P have an angle, the ions collide with the surface including the radiation generation source. Easier to disappear. Therefore, it is desirable that the spray direction is parallel to the surface of the measurement object P including the radiation source.

  Further, uranium contaminants important as the measurement object P emit alpha rays. Since the maximum range of the α rays is about 4 cm, the ions immediately after the generation are present within a distance of about 4 cm from the surface including the radiation generation source of the measurement object P. Therefore, when measuring uranium contaminants as the measurement object P, it is preferable to perform the measurement within 4 cm from the surface including the radiation source.

  Here, radon has the largest contribution among the natural radiation that causes noise. Since radon emits α rays, a decrease in the number of ions generated from the surrounding radon is suppressed at the same time as a decrease in the number of ions of radiation generated by the measurement object P due to the airflow in the airflow acceleration region a. Will increase noise. Further, noise is ions due to natural radiation generated in the entire airflow acceleration region a, and the longer the ion transport time from the generation position to the first ion collection unit 15, the more it disappears due to recombination reaction of ions and adhesion to the aerosol. Probability increases.

  Therefore, the radiation measuring apparatus 10C includes, as an eleventh component, an arrangement adjustment table 77 on which the measurement object P is placed and the measurement object P is arranged at a position different from the position of the airflow that has the maximum flow velocity. May be. By arranging the measurement object P by the arrangement adjustment table 77, ions generated from radon existing at the position have a longer transport time than the position of the maximum flow velocity, and the disappearance probability becomes higher. As a result, the relative contribution to noise can be reduced, and the increase in noise can be suppressed. On the other hand, for the ions generated from the measurement object P, although the probability of annihilation is similarly increased, by selecting an installation position where the effect of reducing the number of ions immediately after generation by spraying is greater than the effect of annihilation, S The / N (Signal / Noise) ratio is improved and the measurement accuracy is improved.

  On the other hand, the flow velocity of the gas in the airflow non-acceleration region is slower than the flow velocity of the gas in the airflow acceleration region a, but in general, the BG component is mainly present in the airflow non-acceleration region. The contribution of BG ions can be reduced.

  According to the radiation measuring apparatus 10 </ b> C and the radiation measuring method shown in FIG. 18, by having the tenth component, that is, the gas blowing unit 76, the cosmic rays in the current collected by the first ion collecting unit 15, etc. The contribution component can be reduced, and the radiation dose of the measurement object P can be measured accurately, accurately, and efficiently.

  In addition, according to the radiation measuring apparatus 10C and the radiation measuring method, by having the gas blowing unit 76, the decrease and fluctuation of the measured current value can be suppressed, and the radiation dose of the measurement object P can be accurately and efficiently controlled. Measurement can be performed.

  Furthermore, according to the radiation measuring apparatus 10C and the radiation measuring method, the S / N can be improved by having the tenth and eleventh components, that is, the gas blowing unit 76 and the position adjustment table 77, and the accurate In addition, the radiation dose of the measurement object P can be measured with high accuracy and efficiency.

  FIG. 22 is a schematic view showing a fifth embodiment of the radiation measuring apparatus according to the present invention.

  FIG. 22 shows the radiation measurement apparatus 10D. The radiation measurement apparatus 10D includes a measurement object storage unit 11, a first ion collection unit 15, a first high-voltage power supply device 17, a fan 20 (shown in FIG. 1), a first current measurement unit 21, and a current correction unit 22. . Further, the radiation measuring apparatus 10 includes a gas inlet 23, a gas collection nozzle 24, a buffer tank 25 (shown in FIG. 1), a gas path 32 (shown in FIG. 1), a filter 33 (shown in FIG. 1), and a gas cleaner. A device 34 (shown in FIG. 1) is provided.

  Then, as described with reference to FIG. 1, the radiation measuring apparatus 10 </ b> D uses the fans 20 a and 20 b to move the gas in the measurement object storage unit 11 from the gas collection nozzle 24 to the gas path 32 a, the first ion collection unit 15, and the buffer tank. 25a, fan 20a, filter 33a, gas path 32b, buffer tank 25b, fan 20b, second ion collection unit 55, gas inflow unit 23, and gas 33 A road shall be formed.

  In addition, as a twelfth component, the radiation measuring apparatus 10 </ b> D includes a gas blowing unit 76 that blows gas against the surface including the radiation source of the measurement target P in the measurement target storage unit 11, and the gas spraying thereof. A flow rate control unit 78 that controls the flow rate of the gas blown from the unit 76, and a radiation discrimination unit 79 that discriminates the type of radiation from the relationship between the flow rate of the gas blown from the gas blowing unit 76 and the current value. The CPU (not shown) functions as the flow rate control unit 78 and the radiation discriminating unit 79 by executing a program built in a storage device (not shown). A specific circuit may be used.

  The fans 20a and 20b are operated, and the first high voltage power supply device 17 for the first ion collector 15 is activated. In addition, when the gas blowing unit 76 is operated via the flow rate control unit 78, the flow rate of the gas in the airflow acceleration region a changes, and the first ion collection unit 15 is provided for each flow rate of the blowing gas controlled by the flow rate control unit 78. Collect ions. The current measured by the first current measuring unit 21 is sent to the radiation discriminating unit 79.

  The radiation discriminating unit 79 discriminates the type of radiation based on the difference in current value for each flow velocity of the blowing gas. Here, among the radiations, β-rays, γ-rays, and cosmic rays have a low number density of ions immediately after generation, so that the effect of lowering the number of ions due to ion recombination reaction immediately after generation is small. Therefore, for example, β-rays, γ-rays, and cosmic rays to the first measured current value measured when the gas is blown from the gas blowing unit 76 and the second measured current value measured when the gas is not blown. The contribution can be regarded as the same level, and the difference between the first measurement current value and the second measurement current value can be regarded as the current caused by α rays and heavy particles. Furthermore, when the radiation important for measurement is α-rays and the contribution of other heavy particles can be ignored, the difference between the first measurement current value and the second measurement current value is the current caused by only α-rays. Become. The radiation discriminating unit 79 discriminates α rays and β rays by performing an operation for taking a difference between the first measurement current value and the second measurement current value and performing an appropriate correction operation, thereby improving the measurement accuracy of the radiation dose. improves.

  In addition, it demonstrates about the case where the kind of radiation is discriminated from the difference of the 1st measured current value measured when gas is sprayed from the gas spraying part 76, and the 2nd measured current value measured when gas is not sprayed. However, the present invention is not limited to this case. For example, by managing the flow rate of the gas blown by the flow rate control unit 78, the degree of ion recombination reaction can be set arbitrarily, and higher measurement accuracy can be obtained.

  According to the radiation measuring apparatus 10 </ b> D and the radiation measuring method shown in FIG. 22, the type of radiation is discriminated by including the twelfth component, that is, the gas blowing unit 76, the flow rate control unit 78, and the radiation discriminating unit 79. Therefore, the radiation dose of the measurement object P can be measured accurately and accurately.

  FIG. 23 is a schematic view showing a sixth embodiment of the radiation measuring apparatus according to the present invention.

  FIG. 23 shows the radiation measurement apparatus 10E. The radiation measurement apparatus 10E includes a measurement object storage unit 11, a first ion collection unit 15 (shown in FIG. 1), a first high-voltage power supply device 17 (shown in FIG. 1), a fan 20 (shown in FIG. 1), a first 1 has a current measurement unit 21 (shown in FIG. 1) and a current correction unit 22 (shown in FIG. 1). Further, the radiation measuring apparatus 10 includes a gas inlet 23, a gas collection nozzle 24, a buffer tank 25 (shown in FIG. 1), a gas path 32 (shown in FIG. 1), a filter 33 (shown in FIG. 1), and a gas cleaner. A device 34 (shown in FIG. 1) is provided.

  Then, as described with reference to FIG. 1, the radiation measuring apparatus 10 </ b> E uses the fans 20 a and 20 b to move the gas in the measurement object storage unit 11 from the gas collection nozzle 24 to the gas path 32 a, the first ion collection unit 15, and the buffer tank. 25a, fan 20a, filter 33a, gas path 32b, buffer tank 25b, fan 20b, second ion collection unit 55, gas inflow unit 23, and gas 33 A road shall be formed.

  Further, the radiation measuring apparatus 10E includes, as a thirteenth component, an airflow stirring unit, for example, a fan 80, that stirs the airflow around the surface including the radiation generation source of the measurement target P. Therefore, in the measurement object storage unit 11, an air flow stirring region b in which the air flow is stirred is generated. The electric fan 80 may be controlled by a CPU (not shown).

  The fans 20a and 20b are operated, and the first high voltage power supply device 17 for the first ion collector 15 is activated. Moreover, when the electric fan 80 is operated, the airflow in the airflow stirring region b is stirred, and the number density of ions immediately after generation decreases.

  FIG. 24 is a diagram for explaining the relationship between gas agitation and the number density of ions immediately after generation.

  When the air flow in the air flow stirring region b is stirred in order to reduce the number density of ions immediately after generation, the diffusion coefficient D of the formula (1) increases, and the number density can be reduced in a short time. Therefore, by stirring the airflow in the airflow stirring region b with the electric fan 80, the decrease in the number of ions due to the recombination reaction of ions immediately after the generation can be reduced, and the decrease in the measurement current and fluctuation can be suppressed.

  Note that uranium contaminants important as the measurement object P emit alpha rays. Since the maximum range of the α rays is about 4 cm, the ions immediately after the generation are present within a distance of about 4 cm from the surface including the radiation generation source of the measurement object P. Therefore, when measuring uranium contaminants as the measurement object P, it is desirable to stir an air flow within 4 cm from the surface including the radiation source.

  In addition, although the electric fan 80 is used to stir the airflow in the airflow stirring region b, a rotary table (not shown) on which the measurement target P is placed is installed, and the rotary table on which the measurement target P is placed is installed. By rotating, the airflow in the airflow stirring region b may be stirred.

  According to the radiation measuring apparatus 10E and the radiation measuring method shown in FIG. 23, since the decrease in the current and the fluctuation can be suppressed by having the thirteenth component, that is, the electric fan 80, the measurement can be performed accurately and accurately. The radiation dose of the object P can be measured.

  FIG. 25 is a schematic view showing a seventh embodiment of the radiation measuring apparatus according to the present invention.

  FIG. 25 shows the radiation measurement apparatus 10F. The radiation measurement apparatus 10F includes a measurement object storage unit 11, a first ion collection unit 15, a first high-voltage power supply device 17 (shown in FIG. 1), fans 20a and 20b (shown in FIG. 1), and a first current measurement unit. 21 (shown in FIG. 1) and a current correction unit 22 (shown in FIG. 1). Further, the radiation measuring apparatus 10 includes a gas inlet 23, a gas collection nozzle 24, buffer tanks 25a and 25b (shown in FIG. 1), and gas paths 32a and 32b (shown in FIG. 1) filters 33a and 33b (shown in FIG. 1). And a gas cleaning device 34 (shown in FIG. 1).

  In addition, the radiation measuring apparatus 10F has, as a fourteenth component, a fourth ion that collects ions in the gas on the downstream side of the first ion collection unit 15 (the downstream side of the buffer tank 25a in FIG. 25). It has the collection part 81 and the 4th high voltage power supply device 82 as a power supply part which applies a voltage to electrode Sd of the 4th ion collection part 81. FIG. The operation of the fourth ion collector 81 and the fourth high voltage power supply device 82 may be controlled by a CPU (not shown).

  The fans 20a and 20b are operated to activate the first high voltage power supply device 17 for the first ion collection unit 15 and the fourth high voltage power supply device 82 for the fourth ion collection unit 81. During the measurement by the first current measuring unit 21, when the α-ray source adhering to the measurement object P is scattered and adhering to the buffer tank 25 a, for example, it cannot be collected by the first ion collecting unit 15. Further, since the α-ray source can be captured by the filter 33a, there is almost no contamination downstream of the filter 33a.

  Therefore, ions are collected by the fourth ion collection unit 81 provided downstream of the buffer tank 25a and in front of the filter 33a. Thereby, ions ionized by α rays can be reduced between the first ion collector 15 and the filter 33a.

  In addition, a fourth current measurement unit 83 that measures the ions collected by the first ion collection unit 15 as a current is provided, and the operator outputs the current value from the fourth current measurement unit 83 so that the operator can obtain the first ion collection unit. The amount of ions ionized by α rays can be monitored between 15 and the filter 33a. That is, the operator can monitor contamination between the first ion collector 15 and the filter 33a. This monitoring can be continuously performed while measuring the radiation of the normal measurement object P, and the presence or absence of scattering of the α-ray source can be measured in real time. In addition, when an abnormality occurs, the operator can easily stop radiation measurement and take measures such as contamination measurement.

  Further, by using a reversible fan as the fans 20a and 20b, the radiation flow between the first ion collector 15 and the filter 33a is measured only by the first ion collector 15 by reversing the gas flow after the end of normal measurement. Can be implemented.

  According to the radiation measurement apparatus 10F and the radiation measurement method shown in FIG. 25, the normal radiation measurement is audited by including the fourteenth component, that is, the fourth ion collector 81 and the fourth high-voltage power supply device 82. However, by detecting the scattering of the radiation into the measurement object storage unit 11, it is possible to assist in the case where an abnormality occurs, and the radiation dose of the measurement object P can be accurately and efficiently determined. Measurement can be performed.

1 is a schematic diagram showing a first embodiment of a radiation measuring apparatus according to the present invention. The figure which shows an example of the change of the sensitivity with respect to the measurement object of a pipe shape as a graph. The figure which shows an example of the correspondence table | surface of the combination of ion collection efficiency and ionization space (radiation source efficiency), and the correction coefficient of a sensitivity. The figure which shows an example of a change of the electric current value with respect to the rotation angle of the rotary table which mounted the pipe-shaped measuring object. The cross-sectional view which shows the structural example of the electrically conductive sheet wound around the inner surface of a measuring object. (A) is a figure which shows the relationship between the temperature in gas, and the detection lower limit of ion as a graph, (b) is a figure which shows the relationship between the humidity in gas, and the detection lower limit of ion as a graph. The figure which shows the transition of the time series of the temperature of the air in a circulation flow path, humidity, and BG current value as a graph. The flowchart which shows the radiation measuring method which concerns on this invention. The figure which shows the 1st modification of the radiation measuring method which concerns on this invention as a flowchart. The figure which shows the pulse-shaped electric current change. The figure which shows the 2nd modification of an effect | action of a radiation measuring device as a flowchart. The figure which shows the relationship between a measurement object accommodating part and BG electric current value. Schematic which shows 2nd Embodiment of the radiation measuring device which concerns on this invention. The figure which shows the effect | action of 2nd Embodiment of the radiation measuring device which concerns on this invention as a schematic diagram. The figure which shows the breakdown of the electric current resulting from the ion collected by the 3rd ion collection part as a graph. Schematic which shows 3rd Embodiment of the radiation measuring device which concerns on this invention. The figure which shows the effect | action of 3rd Embodiment of the radiation measuring device which concerns on this invention as a schematic diagram. Schematic which shows 4th Embodiment of the radiation measuring device which concerns on this invention. The figure for demonstrating the relationship between ion recombination reaction and the number of ions. The figure which shows the relationship between the flow velocity of gas, and an electric current value as a graph. The figure which shows the relationship between the gas flow velocity and theoretical calculation value ratio, and the approximate straight line of the relationship as a graph. Schematic which shows 5th Embodiment of the radiation measuring device which concerns on this invention. Schematic which shows 6th Embodiment of the radiation measuring device which concerns on this invention. The figure explaining the relationship between gas stirring and the number density of the ion immediately after production | generation. Schematic which shows 7th Embodiment of the radiation measuring device which concerns on this invention.

Explanation of symbols

10, 10A, 10B, 10C, 10D, 10E, 10F Radiation measurement device 11 Measurement object storage unit 15 First ion collection unit 17 First high voltage power supply device 20a, 20b Fan 21 First current measurement unit 22 Current correction unit 25a , 25b Buffer tank 24 Gas collection nozzle 38 Shape / correction coefficient acquisition unit 39 Rotary table 40 Rotation control unit 42 Charging state determination unit 43 Charge amount / correction coefficient acquisition unit 44a Surface potential meter 47 Temperature / humidity control unit 48 Temperature / humidity / correction coefficient Acquisition unit 51 Activated carbon 53 Gas replacement unit 54 Injection ratio / correction coefficient acquisition unit 55 Second ion collection unit 56 Second high voltage power supply device 57 Second current measurement unit 58 BG current evaluation unit 61 Electric field shield unit 62 Third ion collection unit 63 Third high-voltage power supply device 65 Ground portions 71a and 72b Charged material 76 Gas blowing portion 77 Arrangement adjustment table 78 Flow The fourth ion collection unit 82 control unit 79 radiation discriminating section 80 Fan 81 fourth high voltage power source device 83 fourth current measuring unit

Claims (27)

A measurement object container for accommodating a measurement object that emits radiation together with a gas; and
An ion collector that collects ions in the gas flowing out of the measurement object storage unit;
A power supply for applying a voltage to the electrodes of the ion collector;
While sending the gas in the measurement object storage unit to the ion collection unit, the gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit,
A current measuring unit that measures the ions collected by the ion collecting unit as a current;
Based on a correspondence table between the shape of the measurement object and the correction coefficient of sensitivity, a correction coefficient acquisition unit that acquires a correction coefficient corresponding to the shape of the measurement object;
A current correction unit that corrects the current value output from the current measurement unit with the correction coefficient output from the correction coefficient acquisition unit, and measures the radiation dose of the measurement object from the corrected current value. A radiation measurement device. The measurement object storage unit includes a rotation table that rotates the measurement object mounted thereon, and a rotation control unit that controls rotation of the rotation table. The ions collected by the ion collector are measured as a current corresponding to the rotation angle of the measurement object, and the current correction unit is a correction coefficient obtained by the correction coefficient acquisition unit. The radiation measuring apparatus according to claim 1, wherein the radiation correction apparatus determines whether or not the correction coefficient of sensitivity is appropriate based on fluctuations caused by the rotation angle of the corrected current value. A gas spray unit that rotates around the measurement object and blows the gas onto the measurement object, and a rotation control unit that controls the rotation of the gas spray part, the current measurement unit, The ion collected by the ion collecting unit is measured as a current corresponding to the spray angle of the measurement object, and the current correction unit is a correction coefficient obtained by the correction coefficient obtaining unit. The radiation measurement apparatus according to claim 1, wherein the radiation correction apparatus determines whether or not the correction coefficient of sensitivity is appropriate based on fluctuations caused by the spray angle of the corrected current value. A measurement object container for accommodating a measurement object that emits radiation together with a gas; and
An ion collector that collects ions in the gas flowing out of the measurement object storage unit;
A power supply for applying a voltage to the electrodes of the ion collector;
While sending the gas in the measurement object storage unit to the ion collection unit, the gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit,
A current measuring unit that measures the ions collected by the ion collecting unit as a current;
Based on a correspondence table between the charge amount of the measurement object and the correction coefficient of sensitivity, a correction coefficient acquisition unit that acquires a correction coefficient of sensitivity corresponding to the charge amount of the measurement object;
A current correction unit that corrects the current value output from the current measurement unit with the correction coefficient output from the correction coefficient acquisition unit, and measures the radiation dose of the measurement object from the corrected current value. A radiation measurement device. The correction coefficient acquisition unit is configured to measure the measurement object based on a correspondence table between the charge amount of the measurement object and the correction coefficient of sensitivity obtained by measuring in advance the sensitivity corresponding to the charge amount of the measurement object. The radiation measurement apparatus according to claim 4, wherein a correction coefficient for sensitivity corresponding to the amount of charge is acquired. A charging state determination unit that determines a charging state of a measurement object that emits radiation; and
A charge removal unit that removes the charge of the measurement object according to the charge state of the measurement object by the charge state determination unit;
A measurement object storage section for storing the measurement object together with a gas;
An ion collector that collects ions in the gas flowing out of the measurement object storage unit;
A power supply for applying a voltage to the electrodes of the ion collector;
While sending the gas in the measurement object storage unit to the ion collection unit, the gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit,
A current measuring unit that measures the ions collected by the ion collecting unit as a current;
A radiation measurement apparatus comprising: a current correction unit that measures a radiation dose of the measurement object from a current value measured by the current measurement unit. A measurement object container for accommodating a measurement object that emits radiation together with a gas; and
An ion collector that collects ions in the gas flowing out of the measurement object storage unit;
A power supply for applying a voltage to the electrodes of the ion collector;
While sending the gas in the measurement object storage unit to the ion collection unit, the gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit,
A radioactive gas collector for collecting radioactive gas in the gas;
A current measuring unit that measures the ions collected by the ion collecting unit as a current;
A radiation measurement apparatus comprising: a current correction unit that measures a radiation dose of the measurement object from a current value measured by the current measurement unit. A measurement object container for accommodating a measurement object that emits radiation together with a gas; and
An ion collector that collects ions in the gas flowing out of the measurement object storage unit;
A power supply for applying a voltage to the electrodes of the ion collector;
While sending the gas in the measurement object storage unit to the ion collection unit, the gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit,
A temperature and humidity control unit for controlling at least one of the temperature and humidity of the gas;
A current measuring unit that measures the ions collected by the ion collecting unit as a current;
A radiation measurement apparatus comprising: a current correction unit that measures a radiation dose of the measurement object from a current value measured by the current measurement unit. Based on a correspondence table between the gas temperature and the sensitivity correction coefficient, the correction coefficient acquisition unit acquires a correction coefficient corresponding to the temperature, and the current correction unit converts the current value into the correction coefficient acquisition unit. The radiation measuring apparatus according to claim 8, wherein correction is performed using a correction coefficient output from the apparatus. Based on a correspondence table between the humidity of the gas and the correction coefficient of sensitivity, the correction coefficient acquisition unit acquires a correction coefficient corresponding to the humidity, and the current correction unit acquires the current value as the correction coefficient acquisition unit. The radiation measuring apparatus according to claim 8, wherein correction is performed using a correction coefficient output from the apparatus. A measurement object container for accommodating a measurement object that emits radiation together with a gas; and
An ion collector that collects ions in the gas flowing out of the measurement object storage unit;
A power supply for applying a voltage to the electrodes of the ion collector;
While sending the gas in the measurement object storage unit to the ion collection unit, the gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit,
A gas replacement unit for replacing a part of the gas;
A current measuring unit that measures the ions collected by the ion collecting unit as a current;
A radiation measurement apparatus comprising: a current correction unit that measures a radiation dose of the measurement object from a current value measured by the current measurement unit. The radiation measuring apparatus according to claim 11, wherein the gas replacement unit injects air having a lower humidity than the gas into the measurement object storage unit. Based on a correspondence table between the air ratio and the sensitivity correction coefficient, the correction coefficient acquisition unit acquires a correction coefficient corresponding to the ratio, and the current correction unit converts the current value into the correction coefficient acquisition unit. The radiation measurement apparatus according to claim 11, wherein correction is performed using a correction coefficient output from the apparatus. A measurement object container for accommodating a measurement object that emits radiation together with a gas; and
A first ion collector that collects ions in the gas that has flowed out of the measurement object container;
A first power supply for applying a voltage to the electrodes of the first ion collector;
A gas transport unit that sends the gas in the measurement object storage unit to the first ion collection unit, circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit, and
A first current measuring unit that measures the ions collected by the first ion collecting unit as a current;
A second ion collector that collects ions in the gas before activation of the first power supply;
A second power source that applies a voltage to the electrodes of the second ion collector before the first power source is activated;
A radiation measurement apparatus comprising: a current correction unit that measures a radiation dose of the measurement object from a current value measured by the first current measurement unit. A second current measurement unit that measures the ions collected by the second ion collection unit as a current, and a BG current evaluation that evaluates the current measured by the second current measurement unit as a current caused by BG (Back Ground) ions The radiation measuring apparatus according to claim 14, wherein the current correction unit corrects the current value with a current value output from the BG current evaluation unit. A grounding part for grounding the measurement object that emits radiation;
A measurement object storage section for storing the measurement object together with a gas;
A first ion collector that collects ions in the gas that has flowed out of the measurement object container;
A first power supply for applying a voltage to the electrodes of the first ion collector;
An electric field shield part that is provided inside the measurement object container, shields the measurement object from an electric field, and guides ions in the measurement object container to the direction of the first ion collector,
A third ion collector for collecting ions outside the electric field shield part, provided inside the measurement object container;
A third power source that applies a voltage to the electrodes of the third ion collector;
A gas transport unit configured to send the gas in the measurement object storage unit to the first ion collection unit and return the gas sent to the first ion collection unit to the measurement object storage unit to circulate the gas; ,
A first current measuring unit that measures the ions collected by the first ion collecting unit as a current;
A radiation measurement apparatus comprising: a current correction unit that measures a radiation dose of the measurement object from a current value measured by the first current measurement unit. The radiation measuring apparatus according to claim 16, wherein the third ion collector is provided inside the measurement object container and is a charged substance that collects ions outside the electric field shield. A measurement object container for accommodating a measurement object that emits radiation together with a gas; and
An ion collector that collects ions in the gas flowing out of the measurement object storage unit;
A power supply for applying a voltage to the electrodes of the ion collector;
While sending the gas in the measurement object storage unit to the ion collection unit, the gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit,
A gas spray unit that sprays the gas onto the surface of the measurement object including the radiation source;
A current measuring unit that measures the ions collected by the ion collecting unit as a current;
A radiation measurement apparatus comprising: a current correction unit that measures a radiation dose of the measurement object from a current value measured by the current measurement unit. The radiation measuring apparatus according to claim 18, wherein the gas spraying unit sprays a gas having a flow velocity of 1 m / s or more onto a surface of the measurement object including a radiation generation source. The radiation measuring apparatus according to claim 18, wherein the gas spraying unit sprays the gas in parallel to a surface including a radiation generation source of the measurement object. The radiation measurement apparatus according to claim 18, wherein the gas spray unit sprays the gas within 4 cm from a surface including a radiation source of the measurement object. The radiation measurement apparatus according to claim 18, further comprising an arrangement adjustment table on which the measurement object is placed and the measurement object is arranged at a position different from a position of the airflow having the maximum flow velocity. A flow rate control unit that controls a flow rate of gas blown from the gas blowing unit, and a radiation discriminating unit that discriminates the type of radiation from the relationship between the flow rate of gas blown from the gas blowing unit and the current. The radiation measuring apparatus according to claim 18. A measurement object container for accommodating a measurement object that emits radiation together with a gas; and
An ion collector that collects ions in the gas flowing out of the measurement object storage unit;
A power supply for applying a voltage to the electrodes of the ion collector;
While sending the gas in the measurement object storage unit to the ion collection unit, the gas transport unit that circulates the gas by returning the gas sent to the ion collection unit to the measurement object storage unit,
An airflow stirring unit for stirring the airflow around the surface including the radiation source of the measurement object;
A current measuring unit that measures the ions collected by the ion collecting unit as a current;
A radiation measurement apparatus comprising: a current correction unit that measures a radiation dose of the measurement object from a current value measured by the current measurement unit. 25. The radiation measuring apparatus according to claim 24, wherein the airflow stirring unit stirs an airflow within an area of 4 cm from a surface including a radiation source of the measurement object. A measurement object container for accommodating a measurement object that emits radiation together with a gas; and
A first ion collector that collects ions in the gas that has flowed out of the measurement object container;
A first power supply for applying a voltage to the electrodes of the first ion collector;
A fourth ion collector that collects ions in the gas downstream of the first ion collector;
A fourth power source that applies a voltage to the electrodes of the fourth ion collector;
While sending the gas in the measurement object container to the ion collector, the gas sent to the ion collector is returned to the measurement object container to circulate the gas, while reversing the circulation of the gas. A gas transporting section,
A first current measuring unit that measures the ions collected by the first ion collecting unit as a current;
A radiation measurement apparatus comprising: a current correction unit that measures a radiation dose of the measurement object from a current value measured by the first current measurement unit. A measurement object that emits radiation is accommodated in a measurement object container together with a gas, and the gas sent from the measurement object container to the ion collector is returned from the ion collector to the measurement object container. In the radiation measuring method for measuring the radiation dose of the measurement object by measuring the ions in the gas collected by the ion collecting unit as a current by forming a circulation flow path,
A shape / correction coefficient acquisition step for acquiring a shape / correction coefficient, which is a sensitivity correction coefficient corresponding to the shape of the measurement object, based on a sensitivity correction coefficient corresponding to the shape of the measurement object;
If the measurement object is charged, or if the charge amount of the measurement object is greater than or equal to a threshold value, a charge removal step of discharging the measurement object;
When the measurement object is charged, a charge amount / correction coefficient acquisition step of acquiring a charge amount / correction coefficient that is a correction coefficient of sensitivity corresponding to the charge amount of the measurement object;
A temperature / humidity / correction coefficient acquisition step of acquiring a temperature / humidity / correction coefficient that is a correction coefficient of sensitivity corresponding to at least one of the temperature and humidity of the gas;
A gas replacement step of injecting air with low humidity compared to the gas and replacing the gas;
An injection ratio / correction coefficient acquisition step of acquiring an injection ratio / correction coefficient which is a correction coefficient of sensitivity corresponding to the air ratio;
A shape / correction coefficient appropriateness determining step for determining that the shape / correction coefficient is appropriate when the fluctuation of the current value measured according to the rotation angle of the measurement object is less than a threshold;
When determining that the shape / correction coefficient is appropriate, the current value is corrected by the shape / correction coefficient, the charge amount / correction coefficient, the temperature / humidity / correction coefficient, and the injection ratio / correction coefficient. A radiation measurement method comprising measuring a radiation dose of the measurement object.

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