JP2005249483A - Radiation detector, radiation measuring instrument and radiation measuring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized radiation detector having low direction dependency, and high sensitivity, a radiation measuring instrument using it which is convenient for carrying, and a radiation measuring system using the radiation measuring instrument. <P>SOLUTION: The radiation detector 1 is constituted of a case (substrate) 2, a semiconductor 3 arranged on the case 2, and a detection element 6 provided with the cathode electrode 4 and an anode electrode 5 formed on the semiconductor element 3, a plurality of which are laminated for constituting a prescribed detection spatial volume. A plurality of cathode electrodes 4 and anode electrodes 5 are electrically connected respectively to each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radiation detector, and more particularly to a radiation detector using a semiconductor element, and more particularly to a radiation detector for measuring a dose rate.

  When using a semiconductor to measure radiation, particularly the air dose rate, there is a problem that the detection efficiency for γ rays is low because the thickness of the semiconductor is as small as several tens to several hundreds of μm.

  Therefore, when measuring a field with a low dose rate, it is conceivable to increase the incident detection area (so-called light receiving area) of the semiconductor detection element. However, when the incident detection area is increased, the area ratio between the incident detection surface and the side surface orthogonal to the incident detection surface changes, so that the detection efficiency with respect to the incident direction of radiation changes, and the direction dependency of the detector increases. There is a fear.

  In order to reduce the direction dependency of the air dose rate measurement, the present applicants combined semiconductor detection elements into a polyhedron (for example, regular hexahedron), and the incident detection area for radiation incident from various directions is reduced. A radiation detector devised to be equivalent was proposed.

  In addition, the present applicants proposed a radiation detector for measuring an air dose rate in which one silicon semiconductor detection element having a diameter of 2 inches is divided into four in the plane direction, and an anode and a cathode are respectively installed (patent document). 1).

JP 2002-350550 A

  Combining semiconductor detector elements in a polyhedron shape (eg, regular hexahedron) reduces the direction dependency, but does not directly increase the sensitivity to γ-rays. In order to measure, it is necessary to increase the incident detection area.

  Further, dividing one silicon semiconductor detection element into four in the plane direction and installing an anode and a cathode for each of them does not directly increase the sensitivity to γ rays.

  An object of the present invention is to provide a radiation detector that is small in size so as to be portable and that has a low incidence direction dependency and high sensitivity, a radiation meter that is convenient to carry using the radiation detector, and the radiation measurement. It is providing the radiation measurement system using a vessel. Furthermore, it is also an object to configure the entire apparatus simply and inexpensively.

  According to a first aspect of the present invention, a plurality of detection elements each including a substrate, a semiconductor element disposed on the substrate, and a cathode electrode and an anode electrode formed on the semiconductor element are stacked and predetermined. And a plurality of the cathode electrodes and a plurality of the anode electrodes are electrically connected to each other.

  According to the radiation detector of the present invention, the incident detection area can be substantially increased by stacking a plurality of detection elements. More specifically, the detection elements are stacked, so that the detection leakage of radiation incident from various directions or the undetected transmission of radiation is prevented (that is, the dependency on the incident direction is reduced and improved). As a result, according to the radiation detector of the present invention, highly sensitive dose rate measurement can be performed with low noise and a short detection time, and the detector can be configured to be small and inexpensive.

  Furthermore, the reason why the radiation detector of the present invention has low incidence direction dependency and high sensitivity will be described. FIG. 8 is a schematic diagram for explaining the principle of the radiation detector of the present invention. Referring to FIG. 8, according to the radiation detector of the present invention, the γ-ray incident from the front direction (upper direction in the figure) having the incident detection surface and transmitted through the first layer detection element 6 is It is detected by being detected by the detection element 6 such as two layers. Further, even when the first-layer detection element 6 does not detect the γ-ray incident from an oblique direction so as to graze the first-layer detection element 6, it is detected by the detection element 6 in the second layer or lower of the next stage. Probability is high. Further, γ rays incident obliquely from the side surface are also captured in a wide range by the detection element 6 in the second layer and below. Therefore, the radiation detector of the present invention prevents detection of radiation incident from various directions or prevents transmission of radiation, and therefore has low dependence on the incident direction and high sensitivity.

  In a second aspect, the present invention is connected to the radiation detector, a circuit for amplifying a detection signal output from the radiation detector, storage means for storing a predetermined constant, the circuit and the storage means, A microcomputer that calculates at least radiation-related data based on the amplified detection signal and the predetermined constant, a RAM that is built in or externally installed in the microcomputer and that stores the radiation-related data, and is controlled by the microcomputer. A display unit that displays data relating to the radiation; a power source; and a case that integrally accommodates the radiation detector, the circuit, the storage unit, the microcomputer, the RAM, the display unit, and the power source. A radiation measuring instrument is provided.

  According to the radiation measuring instrument, a dosimeter having a measurement accuracy equivalent to that of a conventional ionization chamber dosimeter, a small size and a light weight and convenient for carrying is provided.

  In a third aspect, the present invention includes a data reader that reads and transmits data stored in the radiation measuring instrument, and an information processing apparatus that receives data transmitted from the data reader. A radiation measurement system is provided. According to this measurement system, it is possible to obtain a radiation distribution in the region (building, facility, etc.) by storing and aggregating the measurement positions corresponding to the measurement values as well as simply collecting the predetermined measurement values. it can.

  According to the present invention, there are provided a radiation detector that is small and particularly sensitive to γ rays, a small and lightweight portable radiation measuring device using the radiation detector, and a radiation measuring system using the radiation detector.

In the embodiment of the present invention, the ratio of the integrated thickness of the semiconductor element to the incident detection area of the semiconductor element (integrated thickness / incident detection area) is set to 20 to 100 [m ⁻¹ ]. For example, when the incident detection surface (light receiving surface) is square and the incident detection area is 10 × 10 ⁻³ m × 10 × 10 ⁻³ m, the integrated thickness is 2.0 × 10 ⁻³ to 10 × 10 ^{−. 3} m.
In the radiation detector of the present invention, preferably, the semiconductor element (detection element) is laminated in 4 layers or more to 20 layers (more layers if necessary).

  The radiation detector of the present invention is suitably used for air dose rate measurement.

  In the embodiment of the present invention, the detection time is varied according to the height of the air dose rate. For example, when preliminary measurement is performed and the air dose rate is low, the detection time is set long in the main measurement, and when the air dose rate is high, the detection time is set short. At this time, in order to reduce the measurement error, the detection time is set for the air dose rate measured in the preliminary measurement by using a standard deviation predetermined for the size of the air dose rate. To do.

  In the radiation measuring instrument of the present invention, preferably, the storage means (ROM) stores a detection time corresponding to the height of the air dose rate, and the radiation detector is based on the detection time stored in the storage means. To detect radiation.

  The radiation measuring instrument of the present invention preferably has stability calculation means for obtaining the stability of measurement data, and the stability calculation means indicates that the measurement data is stable on the display unit arranged in the case. Display.

  In the radiation measuring instrument of the present invention, preferably, the radiation measuring instrument has a mode selection means, and at least the data can be registered in the standard mode, and the display arranged in the case in the time management mode. It is possible to display at least data regarding the workable time or accumulated dose on the section.

  In an embodiment of the present invention, a system using the radiation detector or radiation measuring instrument of the present invention is stored in a radiation measuring instrument carried to the measurement site and the radiation measuring device brought back from the measurement site. A field system comprising: a data reading and charging device for reading and transmitting data and charging the power supply of the radiation measuring device; and a hub information processing device for receiving data transmitted from the data reading and charging device A center side information processing apparatus that receives the data transmitted from the hub information processing apparatus via a network, and a printer connected to the information processing apparatus, The center information processing apparatus aggregates the data transmitted from the plurality of hub information processing apparatuses.

  1A to 1E are views for explaining a radiation detector according to Embodiment 1 of the present invention. 1A is a plan view, FIG. 1B is a front view, FIG. 1C is a right side view, FIG. 1D is a rear view, and FIG. 1E is a wiring diagram.

  1A to 1E, a radiation detector 1 according to a first embodiment of the present invention includes a case (substrate) 2, a semiconductor element 3 disposed on the case 2, and a semiconductor element. A plurality of detection elements 6 each having a cathode electrode 4 and an anode electrode 5 formed on the substrate 3 are stacked to form a predetermined detection space volume, and the plurality of cathode electrodes 4 and the plurality of anode electrodes 5 are respectively provided as electrodes. They are electrically connected to each other via connection leads 7a and 7b.

As the semiconductor element, for example, a Hamamatsu Photonics Si pin diode can be used. For example, 4 to 20 Si semiconductor elements having an incident detection area (light receiving area) of 10 × 10 ⁻³ m × 10 × 10 ⁻³ m and a thickness of 0.5 × 10 ⁻³ m are stacked. As the semiconductor element, a semiconductor other than Si, such as cadmium telluride that can be easily formed into a square, can also be used.

  2A to 2C are views for explaining a radiation detector according to the second embodiment of the present invention. 2A is a plan view, FIG. 2B is a front view, and FIG. 2C is a right side view.

  Referring to FIG. 1B, in the radiation detector according to the first embodiment, the case 2 is used as a substrate. However, referring to FIGS. 2A to 2C, the second embodiment of the present invention is used. In such a radiation detector, a sheet substrate 2 is used as a substrate. FIG. 2C illustrates 7a and 7b that electrically connect the plurality of cathode electrodes 4 and the plurality of anode electrodes 5 to each other. In the detection element 6, the Si pin photodiode 3 and the sheet substrate 2 are fixed by adhesion. The cathode electrode 4 and the anode electrode 5 are drawn out to the sheet substrate 2 by bonding. Pulled out to the sheet substrate 2, the cathode electrode 4 and the anode electrode 5 are connected in parallel by electrode connection lines 7a and 7b, respectively.

  3A to 3C are external views for explaining a radiation measuring instrument according to Embodiment 3 of the present invention. 4A to 4C are configuration block diagrams of a radiation measuring instrument according to Embodiment 3 of the present invention. FIG. 5 is a flowchart for explaining the operation of the radiation detector according to the third embodiment of the present invention.

  Referring to FIG. 3, (A) to (C) show that a radiation measuring instrument 10 according to a third embodiment of the present invention includes a case 11 containing various components, an extendable shaft 12 attached to the case 11, It has the detection part 13 which is arrange | positioned at the front-end | tip of an expansion-contraction shaft and incorporates the radiation detector 1, the display part 14 which displays the data regarding radiation, and various switches 15-18. A wrist holder 19 for carrying the radiation measuring device 10 in a wristwatch shape is attached to the back side of the case 11, and a wrist belt 20 is passed through the wrist holder 19.

  4A to 4C, the radiation measuring instrument 10 includes a radiation detector 1, a circuit (amplifier and discriminator) 31 that amplifies a detection signal output from the radiation detector 1, and radiation measurement. A bias power source 32 for generating a bias voltage to be supplied to the semiconductor element of the device 10, a V2 power source for supplying power to the bias power source 32, a storage means (EEPROM) 41 for storing a predetermined constant, a circuit 31, and a storage means 41. A microcomputer that includes a scaler 43 for setting a measurement range, a timer 44, an arithmetic processing unit 45, and a control processing unit 46, and calculates at least radiation-related data based on the amplified detection signal and a predetermined constant 42, a RAM 47 built in the microcomputer 42 for storing the data, and a microcomputer 42. Via a display unit (LCD display) 14 (see FIG. 3A) for controlling and displaying radiation-related data, at least a V1 power supply 48 for driving the microcomputer 42, and a V1 power supply 48 or a V2 power supply 33 , Radiation detector 1, circuit 31, storage means 41, microcomputer 42 and Ni-MH battery 49 for supplying power for driving display unit 14, radiation detector 1, circuit 31, storage means 41, microcomputer 42, a RAM 47, a case for housing the display unit and the power source integrally.

  The storage means 41 stores a detection time corresponding to the height of the air dose rate. For example, when the air dose rate is low, the detection time is set long to reduce the error, and the dose rate is high. In this case, the detection time is set short, and the radiation detector 1 performs radiation detection based on the set detection time.

  Further, the radiation measuring instrument 1 has a built-in program executed by the arithmetic processing unit 45 as a stability calculation means for obtaining the stability of the measurement data, and the stability calculation means displays a display unit indicating that the measurement data is stable. 14 can be displayed.

  An example of the operation of the radiation measuring apparatus 10 described with reference to FIGS. 3 (A) to 4 will be described. Further, referring to FIG. 5, when the power switch 18 of the radiation measuring instrument 10 is turned on (S1), the standard mode (S2), time management mode (S3), and calendar adjustment are performed by the cursor switch 15 according to the display on the display unit 14. The mode (S10) and registration data transmission (S11) described later can be selected.

  In the standard mode (S2), the data registration memory can be selected (S4) or the measurement data can be registered (S5) by selecting ON / OFF of the cursor switch 15, the setting switch 16 or the data storage / clear switch 17.

  In the time management mode (S3), by selecting ON / OFF of the setting switch 16 and the data storage / clear switch 17, selection of the geometric average calculation data registration memory (S6), registration of measurement data (S7), and measurement dose Either the timer mode (S8) indicating the available work time or the integrated dose mode (S9) can be selectively executed.

  Using the radiation measuring device shown in FIGS. 3 and 4 incorporating the radiation detector shown in FIG. 1, in the Fukushima Daiichi NPS Unit 1 radiation measuring device calibration device room, the measuring device is connected to the sealed radiation source 137Cs. When the gamma ray dose measurement experiment was conducted in the front direction, measurement accuracy equivalent to that of a conventional large ionization chamber dosimeter was obtained.

  FIG. 6 is a view for explaining the radiation detector according to the fourth embodiment of the present invention, and shows the telescopic shaft 12 applicable to the telescopic shaft 12 shown in FIG.

  Referring to FIG. 6, each of the telescopic shafts 12 includes a tip portion 12a, an intermediate portion 12b, and a base portion 12c made of a metal pipe, and electrical connection between the tip portion 12a and the intermediate portion 12b is performed by a sliding electrode 12d. The electrical connection between the part 12b and the base part 12c is made by a sliding electrode 12e.

  According to the telescopic shaft 12, the radiation measuring instrument 1 can be inserted into a narrow space and radiation measurement can be performed, and a noise signal is mixed in data transmission from the radiation detector 1 to the main body side of the radiation measuring instrument 10. Can be highly prevented.

  FIG. 7 is a diagram for explaining the radiation detection system according to the fifth embodiment of the present invention.

  Referring to the left side of FIG. 7 (system on the work site side), the radiation detection system according to Example 5 of the present invention was brought home from the radiation measurement device 10 of the present invention carried at the measurement site and the measurement site. The data measured by the radiation detector 10 is read from the radiation detector 10 and transmitted, and the data reading and charging device 61 for charging the radiation measuring device 10 and the data reading and data transmitted from the charging device 61 are received. And a first personal computer (hub information processing apparatus) 62.

  Referring to the right side (work site side) of FIG. 7, the radiation detection system on the office side according to the third embodiment of the present invention is transmitted from the first personal computer (hub information processing apparatus) 62 through a communication network such as a LAN 63. A second personal computer (center side information processing apparatus) 64 that receives the measured data, and a printer 65 that can print the measurement data processed by the second personal computer 64.

  A first personal computer (hub information processing device) 62 installed in each office aggregates radiation measurement data at a plurality of measurement locations, and further, a second personal computer (center side information processing) installed in the center. (Device) 64 collects the data transmitted from a plurality of first personal computers (hub information processing devices) 62.

  The radiation detector of the present invention is used as a detector for measuring an air dose rate in a nuclear power plant or the like.

(A)-(E) are the figures for demonstrating the radiation detector which concerns on Example 1 of this invention. (A)-(C) are the figures for demonstrating the radiation detector which concerns on Example 2 of this invention. (A)-(C) are the external views for demonstrating the radiation measuring device which concerns on Example 3 of this invention. It is a structure block diagram of the radiation measuring device which concerns on Example 3 of this invention. It is a flowchart for demonstrating operation | movement of the radiation detector which concerns on Example 3 of this invention. It is a figure for demonstrating the radiation detector which concerns on Example 4 of this invention. It is a figure for demonstrating the radiation detection system which concerns on Example 5 of this invention. FIG. 8 is a schematic diagram for explaining the principle of the radiation detector of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radiation detector 2 Board | substrate, case, sheet | seat board | substrate 3 Semiconductor element, Si pin photodiode 4 Cathode electrode 5 Anode electrode 6 Detection element 7a, 7b Electrode connection lead, electrode connection line 10 Radiation measuring instrument 11 Case 12 Telescopic shaft 12a Tip 12b Intermediate part 12c Base part 12d Sliding electrode 12e Sliding electrode 13 Detection part 14 Display part (LCD display)
15 to 18 Various switches 19 Wrist holder 20 Wrist belt 31 Circuit (amplifier and discriminator)
32 Bias power supply 33 V2 power supply 41 Memory means (EEPROM)
42 microcomputer 43 scaler 44 timer 45 arithmetic processing unit 46 control processing unit 47 RAM
48 V1 power supply 49 Ni-MH battery 50 On-site system 51 Center side system 61 Data reader 62 First personal computer (hub information processing apparatus)
63 LAN
64 Second personal computer (center side information processing apparatus)
65 printer

Claims (10)

  A plurality of detection elements each including a substrate, a semiconductor element disposed on the substrate, and a cathode electrode and an anode electrode formed on the semiconductor element are stacked to form a predetermined detection space volume. The radiation detector is characterized in that the cathode electrode and the plurality of anode electrodes are electrically connected to each other. 2. The radiation detector according to claim 1, wherein a ratio of an integrated thickness of the semiconductor element to an incident detection area of the semiconductor element (integrated thickness / incident detection area) is 28 to 100 [m ⁻¹ ].   The radiation detector according to claim 1, wherein four or more semiconductor elements are stacked.   The radiation detector according to claim 1, wherein the radiation detector is used for measuring an air dose rate.   The radiation detector according to claim 4, wherein the detection time is varied according to the height of the air dose rate.   The radiation detector according to any one of claims 1 to 5, a circuit for amplifying a detection signal output from the radiation detector, storage means for storing a predetermined constant, the circuit and the storage means. A microcomputer that calculates at least radiation-related data based on the amplified detection signal and the predetermined constant; a RAM that is built in or external to the microcomputer and that stores the radiation-related data; and is controlled by the microcomputer A display unit that displays data relating to the radiation, a power source, and a case that integrally accommodates the radiation detector, the circuit, the storage unit, the microcomputer, the RAM, the display unit, and the power source. A radiation measuring instrument comprising:   The radiation measuring apparatus according to claim 6, wherein a detection time corresponding to a height of an air dose rate is stored in the storage unit, and the radiation detector performs radiation detection based on the detection time.   7. The radiation measuring apparatus according to claim 6, further comprising stability calculating means for obtaining stability of measurement data, wherein the stability calculating means displays on the display section that the measurement data is stable. 7. The radiation measuring instrument according to 7.   The radiation measuring instrument has a mode selection means, and at least the data can be registered in the standard mode, and in the time management mode, at least the data relating to the measurable time or accumulated dose is displayed on the display unit arranged in the case. The radiation measuring instrument according to claim 6, wherein the radiation measuring instrument can be displayed.   The radiation measuring device according to any one of claims 6 to 9, which is carried at a measurement site, and reading and transmitting data stored in the radiation measurement device brought back from the measurement site, and the radiation measuring device A field system including a data reading / charging device for charging a power supply, and a hub information processing device for receiving data transmitted from the data reading / charging device, and transmission from the hub information processing device via a network A center-side information processing apparatus that receives the data to be received and a printer connected to the information processing apparatus, and the center-side information processing apparatus includes a plurality of pieces of hub information. A radiation measurement system that aggregates the data transmitted from a processing apparatus.

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