JP5935209B2 - Radiation measurement apparatus and survey system - Google Patents

Description

  The present invention relates to a radiation measuring apparatus, and more particularly to a radiation measuring apparatus capable of measuring the direction of radiation (particularly γ rays).

  As a radiation measuring apparatus, a survey meter, a monitoring post and the like are known. They generally do not have directivity and measure the gamma ray air dose or air dose rate. In a radiation measuring apparatus that measures γ-rays, a collimator made of lead or the like is generally added to a detector in order to give directivity to the detection unit. And the detection unit comprised in that way is rotationally driven, and the flight direction of a gamma ray is estimated by specifying a peak on the count value graph obtained by it. However, in such a configuration, the detection unit becomes very large and its weight increases.

  The radiation measuring apparatus disclosed in Patent Document 1 includes a plurality of detectors having different horizontal directivities. The radiation flight direction is specified from the mutual ratio (measured ratio information) of a plurality of count values measured by them. Specifically, for each energy category, a plurality of count values are normalized by their sum and a plurality of actually measured count value ratios are calculated. On the other hand, response functions that provide a plurality of theoretical count value ratios that change in accordance with the flying direction are prepared for each energy category. For each energy category, multiple measured count ratios are collated with the response function, and by specifying the combination of multiple measured count ratios with the highest degree of coincidence, the radiation direction and energy category are estimated simultaneously. The According to this method, it is not necessary to provide a heavy collimator or a rotation mechanism in the detection unit.

  In the radiation measuring apparatus described in Patent Document 1, a scintillator detector is configured by combining three scintillator members having a fan shape when viewed from above. The scintillator detector has a disc shape or a cylindrical shape as a whole. According to this configuration, in each scintillator member, the sensitivity (response) varies depending on the radiation direction.

JP 2007-155332 A

  First, when a scintillator member having a special shape is used, there is a problem that its processing cost increases. In general survey meters, a scintillator member having a simple columnar shape or disk shape is used. It is desired to specify the radiation direction of radiation using a scintillator member having such a simple shape.

  Secondly, when a radiation sensor (for example, a semiconductor sensor) other than the scintillator member is used, there is a problem that the technique for processing the sensor shape as described above cannot be applied.

  Third, the measured flying azimuth is the azimuth viewed from the detection unit, and when the flying azimuth is displayed on a display distant from the detection unit, there is a problem that the display contents are not exactly accurate.

  The present invention aims to solve at least one of the above-described problems.

  More specifically, an object of the present invention is to make it possible to measure the direction of radiation radiation without applying special processing to each sensor. Alternatively, an object of the present invention is to make it possible to easily measure the direction of radiation by using a plurality of scintillator members having a simple shape. Alternatively, an object of the present invention is to make it possible to measure the radiation direction by using a sensor other than the scintillator member. Alternatively, an object of the present invention is to provide a technique capable of easily or accurately displaying the radiation direction.

  A radiation measurement apparatus according to the present invention includes a detection unit having a plurality of sensors for detecting radiation, a filter member in which the plurality of sensors are embedded, and a plurality of measurement values measured using the plurality of sensors. A plurality of sensors in a marginal region near the side peripheral surface of the filter member and spaced apart from each other along the side peripheral surface. It is housed in a plurality of arranged cavities, whereby different horizontal directivity characteristics occur in each of the plurality of sensors.

According to the above configuration, a plurality of cavities are formed along the side peripheral surface in the marginal region in the vicinity of the side peripheral surface (side surface) of the filter member that filters radiation , and a plurality of sensors are embedded therein. Instead of machining the shape of multiple sensors themselves and combining them horizontally to create directional characteristics for individual sensors, multiple sensors are simply placed in multiple cavities formed in the filter member Thus, directivity characteristics can be generated in each sensor. Therefore, special processing of the sensor shape is basically unnecessary. It is desirable to determine the positions of the individual cavities so that the radiation transmission mode (especially the transmission path length) of the filter member varies as much as possible depending on the radiation direction of the radiation when viewed from each sensor. Desirably, the filter member is formed in a simple disk shape, and a plurality of cavities are formed along the side surface thereof and inscribed or close to the side surface. In order to reduce the influence of radiation from other than the horizontal direction, the thickness of the filter member is such that a constant thickness (distance) is generated on the upper side and the lower side of the sensor arranged in each cavity in the entire thickness of the filter member. It is desirable to determine the depth and position of the cavity. For the same reason, a shielding member may be provided on the lower surface (and / or the upper surface) of the filter member. The edge region is a region closer to the side surface than the center of the filter member on the horizontal plane, and if each sensor is arranged in such a region, each sensor has a large response according to the azimuth direction. Variations can be generated, and as a result, the orientation discrimination accuracy can be improved.

  Desirably, the radiation azimuth | direction is determined from the mutual ratio of the some measured value (a count value, a dose rate, etc.) acquired using the some sensor. In that case, it is desirable to perform fitting to the response function described in Patent Document 1 or the like. A plurality of response functions corresponding to a plurality of nuclides may be prepared, and one response function corresponding to the measurement target nuclide may be selected from among them, and the flying direction may be determined using the selected response function. Such a configuration eliminates the need for energy discrimination processing.

  In the above configuration, for example, a plurality of existing survey meters can be used. That is, it is also possible to insert the sensor portions of the plurality of detection probes included in the plurality of survey meters into the plurality of cavities of the filter member and determine the flying direction from the plurality of measured values output from the plurality of survey meter bodies. . It is also possible to obtain a plurality of measurement values by sequentially using one survey meter and thereby determine the flying direction. In that case, a single detection probe is sequentially inserted into the plurality of cavities, and radiation is detected in each inserted state.

  The plurality of cavities (that is, the plurality of sensors) are desirably arranged at equal intervals along the side peripheral surface of the filter member, but they may be arranged at non-uniform intervals. It is desirable to adopt such a configuration when it is desired to perform highly accurate flying azimuth discrimination in a specific azimuth range. However, in that case, it is necessary to prepare and prepare a response function suitable for the sensor arrangement in advance.

  Preferably, each of the plurality of sensors is constituted by a scintillator member, and the filter member is constituted by a member having a radiation transmission characteristic equivalent to that of the scintillator member. According to this configuration, it is possible to determine the flying direction while using a scintillator member having a simple shape. That is, even if the special scintillator shape described in Patent Document 1 is not adopted, it is possible to generate directivity characteristics equivalent to that in each sensor.

  Preferably, each of the plurality of cavities is inscribed or close to a side peripheral surface of the filter member. According to this configuration, when viewed from the center of the filter member, the sensitivity is high with respect to radiation coming from the orientation of each sensor, and the sensitivity is lower when the sensor is deviated from the orientation. That is, the sensitivity difference according to the flying direction can be easily increased. Thereby, the direction discrimination accuracy can be increased. In addition, when each cavity completely contacts the side peripheral surface, the cavity will communicate with the outside through the side peripheral surface. It is desirable to form each cavity in a shifted proximity position. However, for example, a C shape as viewed from above may be adopted as the shape of each cavity. However, when the exposure level of the sensor increases, the peak of the response function tends to become dull. The shape of the filter member is particularly preferably a disc shape. However, a shape in which the side surfaces rise in the horizontal direction between adjacent cavities, that is, between adjacent sensors, may be employed.

  Preferably, a plurality of detection probes are used, and each detection probe includes the scintillator member, a photomultiplier tube that receives light generated by the scintillator member, and a probe that houses the scintillator member and the photomultiplier tube. Each of the cavities is configured as a non-penetrating recess that is continuous with the lower surface or the upper surface of the filter member, and a distal end portion that houses the scintillator member in each detection probe is inserted into each recess. . According to this configuration, it is possible to easily determine the direction using a plurality of existing survey meters. If each cavity is a non-penetrating recess, vertical positioning is facilitated. In addition, it is easy to ensure a certain thickness above and below the sensor. When disposing a display or other structure on the upper surface side of the filter member, it is desirable to form a plurality of recesses opened on the lower surface side of the filter member in order to avoid physical interference.

  Desirably, it further includes a display device provided on the upper surface side of the detection unit and having a display surface facing upward, and the incoming direction of the radiation is displayed on the display surface. Preferably, the orientation display origin on the display surface is located on the vertical center axis of the detection unit. According to this configuration, the flying direction determined using the detection unit can be easily and accurately displayed to the user.

  Desirably, a survey system configured as a movable body or a portable body including the radiation measuring apparatus is provided. For example, a cart-type survey system, a portable survey system, or the like may be configured. Since they have mobility, it is possible to easily and quickly identify a contamination location (a hot spot as a location where radioactive contaminants are concentrated). That is, it is possible to narrow down the contaminated portion while continuously determining the flying direction. It is also possible to measure the flying azimuth at a plurality of positions while moving and to identify the contaminated part by triangulation.

  According to the present invention, it is possible to measure the direction of radiation radiation without applying special processing to each sensor. Alternatively, it is possible to easily measure the radiation direction by using a plurality of scintillator members having a simple shape. Alternatively, the direction of radiation can be measured using a sensor other than the scintillator member. Alternatively, it is possible to easily or accurately display the radiation direction.

It is a block diagram which shows the whole structure of the radiation measuring device which concerns on this invention. It is a disassembled perspective view of a detection unit. It is a top view of a detection unit. It is a partial cross section figure of a detection unit. It is a figure which shows the response function for 1st nuclide. It is a figure which shows the response function for 2nd nuclides. It is a figure which shows the response function for 3rd nuclide. It is a figure which shows the response function for 4th nuclide. It is a figure which shows the response function for 5th nuclide. It is a figure which shows the detection unit carrying a display part. It is a figure which shows the example of a display shown in FIG. It is a conceptual diagram which shows a trolley | bogie type survey system. It is a conceptual diagram which shows a portable survey system.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a preferred embodiment of a radiation measuring apparatus according to the present invention, and FIG. 1 is a block diagram showing the overall configuration thereof. This radiation measurement system is a survey system in the present embodiment, and in particular, is a survey system having a function of determining the incoming direction of radiation (γ rays). The system is configured as a portable device in the present embodiment.

  In FIG. 1, the radiation measuring apparatus is roughly composed of a detection unit 10 and a processing unit 12. The detection unit 10 includes a plurality of detection probes 14, 16, 18 and a filter member 20 in the illustrated example. Preferably, more than two detection probes are utilized. In this embodiment, each detection probe 14, 16, 18 includes a scintillator member and a photomultiplier tube (PMT) as will be described later. They constitute a bar-shaped detector in an existing portable survey meter.

  The filter member 20 has a disk-like form in the illustrated example, and includes three cavities as will be described in detail later, and the tips of the three detection probes 14, 16, 18 with respect to the three cavities. The part is inserted. Each tip portion is a portion containing a scintillator member. The filter member 20 has a simple disk-like or columnar shape, and is constituted by a single member having uniformity. But it is also possible to comprise the filter member 20 as what consists of a some member.

  Since the three scintillator members for detecting each radiation are embedded in the edge region of the filter member 20, each scintillator member has a unique sensitivity characteristic (directional characteristic) in the horizontal direction. The directivity characteristics of the scintillator members are different from each other, and it is possible to determine the radiation flight azimuth using the difference in directivity characteristics as will be described later.

  The three detection probes 14, 16, 18 are connected to the three signal processing units 22, 24, 26, respectively. The three signal processing units 22, 24, and 26 have the same configuration. The configuration of the signal processing unit 22 will be described as a representative. The signal processing unit 22 includes a signal processor 28 and an arithmetic unit 30. The signal processor 28 is a signal processing module having a preamplifier, a wave height discriminator, and the like. The calculator 30 includes a counter, and the calculator 30 calculates a count value, a dose rate, and the like. The signal processing unit 22 is preferably configured as a survey meter body. That is, the configuration including the signal processing unit 22 and the detection probe 14 may be an existing portable survey meter itself. For example, the detection unit 10 and the signal processing units 22, 24, and 26 can be simply constructed by simply using three survey meters as they are and adding the filter member 20 thereto. Note that a multi-channel analyzer (MCA) function or a single channel analyzer (SCA) function may be mounted in the signal processing unit 22.

  In the present embodiment, the measurement target nuclide is designated in advance, and three count values (dose rates) N1, N2, and the like measured by using the three detection probes 14, 16, and 18 for γ rays from the nuclide. N3 is output to the main calculation unit 32. The main arithmetic unit 32 and the main control unit 34 are constituted by, for example, a microcomputer or a personal computer. The main calculation unit 32 executes a calculation for determining the incoming direction of radiation, that is, γ rays. Further, the air dose rate is calculated from the three count values N1, N2, and N3 as necessary. The main control unit 34 controls the operation of the main calculation unit 32. In this embodiment, the main control unit 34 designates a specific response function corresponding to the measurement nuclide from the response function group stored in the memory 36. Yes. The main calculation unit 32 performs azimuth discrimination with reference to the specific response function designated as such.

  The input unit 38 is used for designating the measurement nuclide by the user. In the present embodiment, any nuclide can be designated from among the five nuclides, and a response function corresponding to the thus designated nuclide is referred to in the azimuth discrimination calculation. Instead of such a configuration, a plurality of response functions corresponding to a plurality of energy categories may be prepared, and any one of the energy categories may be designated. The display unit 40 displays the result calculated by the main calculation unit 32, and the determined flying direction is displayed on the display unit 40. Information such as dose rate is displayed as necessary. Although not shown in FIG. 1, the radiation measurement apparatus has a battery, and each component is operated by electric power supplied from the battery. That is, this radiation measuring apparatus is portable, and the radioactive contamination source can be identified reliably and quickly by determining the flying direction at each position while moving. In other words, the radiation measuring apparatus shown in FIG. 1 is a survey system suitable for hot spot detection.

  FIG. 2 is an exploded perspective view of the detection unit 10 shown in FIG. As described above, the detection unit 10 includes the three detection probes 14, 16, 18 and the filter member 20. Three cavities 42, 44, 46 are formed in the filter member 20. Each cavity 42, 44, 46 has an opening formed on the lower surface 20 </ b> A of the filter member 20. Each cavity 42, 44, 46 is a hole having a concave shape that opens downward. These are spaces for sensor installation, and are formed in the edge region of the filter member 20 as viewed from above, and they are formed at equal intervals along the side peripheral surface.

  The diameter of the filter member 20 is 20 cm, for example, and the thickness is 3-5 cm, for example. Each cavity 42, 44, 46 has a cylindrical shape, and the distal end portion of each detection probe 14, 16, 18 is fitted into each cavity 42, 44, 46. The diameter is, for example, several centimeters. Although means for fixing the detection probes 14, 16, and 18 is not shown in FIG. 2, it is desirable to provide such means as necessary. Each detection probe 14, 16, 18 has a scintillator member 48 and a photomultiplier tube 50. A light guide member is provided between the scintillator member 48 and the photomultiplier tube 50. The probe tip portion inserted into each of the cavities 42, 44, 46 is a portion containing at least a scintillator member 48. The scintillator member 48 is made of a NaI scintillator material in this embodiment.

The filter member 20 is preferably composed of a member having radiation transmission characteristics equivalent to the radiation transmission characteristics of the scintillator member 48 in order to make the waveform of the response function close to a sine wave. For example, the filter member 20 is preferably made of a material having a density of 1-3 g / cm ³ . Examples of such a material include resin and glass. The filter member 20 is preferably made of a material having a mass number similar to that of the NaI scintillator material.

  In the configuration example shown in FIG. 2, three detection probes 14, 16, and 18 are arranged. However, four or more detection probes can be arranged. In the configuration example shown in FIG. 2, the three detection probes 14, 16, and 18 are provided at equal intervals along the side peripheral surface, but, of course, they may be arranged at non-uniform intervals. In the illustrated example, three detection probes 14, 16, and 18 are inserted into the filter member 20 from the lower side, but such insertion may of course be performed from the upper side. However, when providing a display unit and other structures on the upper side of the filter member 20, it is desirable to insert a plurality of detection probes from the lower side.

  FIG. 3 shows a top view of the detection unit 10. As described above, the filter member 20 has a disk shape, and the three detection probes 14, 16, and 18 are arranged at equal intervals along the side surface 20B, that is, three cavities are formed. Yes. More specifically, three detection probes 14, 16, and 18 are provided with an angular interval of 120 degrees. In FIG. 3, O represents a center point or a vertical center line. That constitutes the detection origin. Each cavity is substantially inscribed on the side surface 20B. However, a slight thickness may exist between each cavity and the side surface 20B. In the disc-shaped scintillator member 48, it is desirable to form a plurality of cavities in a region closer to the side surface 20B than the center, that is, a peripheral region. That is, if a plurality of sensors are arranged in such an edge region, the difference between peaks and valleys in the response function can be enlarged, and as a result, the direction discrimination accuracy can be increased.

  In FIG. 3, γ rays coming from the radiation source 52 are indicated by reference numeral 54. Detection is performed on each of the detection probes 14, 16, 18, that is, each sensor for such γ-ray 54, and thereby three count values are obtained. Since the mutual ratio of the respective count values differs depending on the flying direction of the γ-ray 54, it is possible to specify the flying direction from the relationship between the counted values. In that case, it is not necessary to rotationally drive the detection unit 10 itself. However, it is possible to provide a rotation mechanism for the detection unit as required.

  FIG. 4 shows a partial cross section of the detection unit. A plurality of cavities are formed in the filter member 20, and one cavity is shown in FIG. 4, and a tip portion of the detection probe 14 is inserted into the filter member 20 from below. Both are in a fitted state. In the arrangement state of the detection probe 14, the scintillator member 48 is completely located inside the filter member 20. That is, on the basis of the scintillator member 48, a certain thickness, that is, a margin exists above and below it. Thus, a certain shielding action against radiation from obliquely above or obliquely below is obtained. Of course, a shielding member may be provided on the upper and lower surfaces of the filter member 20 in order to sharpen the directivity in the horizontal direction. A scintillator member 48 is arranged inside the detection probe 14, and a photomultiplier tube 50 is provided below the light probe member 56 via a light guide member 56. Reference numeral 51 denotes a case for housing the scintillator member 48, the photomultiplier tube 50, and the like, which is made of aluminum having a thickness of about several millimeters. Incidentally, reference numeral 58 denotes a vertical central axis of the filter member 20.

  As described above, in the detection unit 10, different horizontal directivity characteristics are generated for each sensor, and as a result, different responses are generated in each sensor with respect to radiation flying from a specific direction. In this embodiment, the three count values N1, N2, and N3 obtained by the three sensors are each divided and summed by their sum T (= N1 + N2 + N3), that is, the three count ratios N1 / T. , N2 / T, N3 / T are obtained. They can be said to be actual measurement count ratios. It can be understood as the internal ratio with respect to the total count value. By applying a combination of three count ratios (that is, a count ratio sequence) to a specified response function, it is possible to determine that the radiation has a flying direction with the direction having the highest correlation.

  5 to 9 show examples of response functions. FIG. 5 shows the response function for the first nuclide, FIG. 6 shows the response function for the second nuclide, FIG. 7 shows the response function for the third nuclide, and FIG. 8 shows the response for the fourth nuclide. FIG. 9 shows a response function for the fifth nuclide. In each figure, a graph specified by a plurality of circle columns is a graph to be compared with a first count ratio (N1 / T), and a graph specified by a plurality of triangle columns is a second count ratio ( N2 / T), and a graph specified by a plurality of square columns is a graph compared with the third count ratio (N3 / T). That is, each response function is composed of three count ratio graphs, and the three actually measured count ratios are compared with three count ratio graphs theoretically or previously obtained as shown in the figure, It is possible to determine that the direction of radiation has the highest degree of coincidence and that it is the incoming direction of radiation. Such an orientation discrimination method is basically the same as the method described in Patent Document 1 described above. However, in this embodiment, five response functions corresponding to five nuclides with different γ-ray energies are prepared in advance, and the response function corresponding to the nuclide that is the measurement target is selected from among them. The flying azimuth is discriminated with three count ratios using the selected function. This eliminates the need to calculate a count value or the like for each energy in each signal processing unit shown in FIG.

  If the nuclide to be measured is unknown, each function may be selected in order, and the flying direction may be determined from the one with the highest degree of coincidence. Instead of a plurality of response functions corresponding to a plurality of nuclides, a plurality of response functions corresponding to a plurality of energy sections may be prepared. Incidentally, each of the response functions shown in FIGS. 5 to 9 is for explaining the invention and is only an example. Each response function can be created by simulation or experiment. Since the filter member 20 has a disc shape, each graph in each response function basically has a shape close to a sine waveform. In other words, it is possible to manipulate the shape of each graph by manipulating the horizontal form of the filter member. Therefore, it is desirable to determine the shape of the filter member and the arrangement of the cavities so that the peaks and valleys are as large as possible.

  Next, the structure which laminated | stacked the indicator with respect to the detection unit is demonstrated using FIG.10 and FIG.11. FIG. 10 shows the detection unit 10, and a display unit 60 is installed on the upper surface thereof. The display unit 60 is, for example, a liquid crystal display (LCD).

  FIG. 11 shows a display example of the display unit 60. The display unit 60 has a display screen, and in the illustrated example, an orientation indicator 62 is displayed on the display screen. The azimuth indicator 62 is provided with an azimuth marker 64 indicating a flying azimuth, which specifically has an arrow shape. The center of the orientation indicator 62, that is, the origin of the orientation marker 64 coincides with the measurement origin of the detection unit 10, in other words, the center point of the orientation indicator 62 is positioned on the vertical center line of the detection unit 10. As a result, the flying direction of the radiation 54 determined using the detection unit 10 can be accurately displayed on the display unit 60. That is, it is possible to reflect the flying direction when the detection unit 10 is taken as a reference on the detection unit 10 as it is, and recognize the direction without error even when radioactive contamination occurs in the near field. Is possible. In addition, there is an advantage that the error can be reduced even when the flying direction is determined at a plurality of points by using the trigonometric method and the contamination source is identified from them.

  On the display surface, a numerical display 66 and a dose rate display 68 of the flying direction are also included in the present embodiment. Here, the dose rate can be calculated by performing conversion from three count values (three dose rates). Alternatively, a normal detection unit may be provided separately, and the dose rate may be calculated based on the detection result. A nuclide display 70 is further included on the display surface. It is a display showing the nuclide that is the object of measurement.

  FIG. 12 shows a configuration example of a cart-type survey system in which the radiation measuring apparatus described above is incorporated.

  The cart body 72 includes four casters 76. It is a caster that can turn two front wheels or two rear wheels. It is possible to move the cart main body 72 to an arbitrary position on the ground 74 by using such casters 76. The carriage main body 72 is provided with a handle 78, which functions as a handle. The carriage body 72 is moved by human power. However, an electric motor or the like may be mounted.

  The detection unit 10 is provided on the carriage main body 72 via a pedestal 82. A display unit 60 is provided on the upper surface side of the detection unit 10. Such a laminated structure is as shown in FIGS. The detection unit 10 detects γ rays 80 flying from the surroundings.

  A battery 86 is provided inside the housing 84, and power is supplied to each component by the battery 86. A personal computer (PC) 88 is installed on the housing 84. Of course, a dedicated controller may be provided. The PC 88 includes the main calculation unit 32, the main control unit 34, the memory 36, and the like in the configuration shown in FIG. Incidentally, it is desirable to provide a pollution prevention cover 90 when radioactive contamination of the system itself becomes a problem. Such a cover 90 is comprised by transparent films, such as a polypropylene, for example. If it becomes contaminated, it can be replaced with a new one.

  According to the cart type survey system shown in FIG. 12, it is possible to quickly and surely narrow down the contamination source by measuring the orientation of the contamination source at each position while moving the cart while holding the handle 78. That is, there is an advantage that a hot spot can be detected quickly. For example, when high-dose contamination occurs locally in school grounds or on roads, use the system shown in Fig. 12 to identify the location and quickly apply the necessary decontamination measures. Is possible. In the configuration example shown in FIG. 12, a carriage is the base, but a similar configuration may be mounted on a moving body such as an automobile.

  FIG. 13 shows a configuration example of a portable survey system.

  (A) shows a top view, and (B) shows a side view. The portable survey system is roughly composed of a head 100 and a grip 102. That is, it is operated with one hand. The head 100 has a disc shape, and is constituted by a detection unit 106 and a display unit 104 as shown in FIG. Both have a disk shape. The detection unit 106 includes a filter member 118 and three sensors 112, 114, and 116 embedded therein, and the three sensors are arranged in the circumferential direction with an angular interval of 120 degrees. Each sensor 112, 114, 116 is constituted by a semiconductor sensor in the illustrated example.

  The display unit 104 is configured by a liquid crystal display, which includes an orientation marker 108 as an orientation indicator and an information display unit 110. The azimuth marker 108 displays the radiation azimuth. In the example shown to (A), the radiation has come from the left direction, and the direction marker 108 points to the direction. The information display unit 110 is a part for displaying various information such as a dose rate, a numerical value as a direction, and a measurement target nuclide.

  The grip 102 is a part that is gripped with one hand, and a microcomputer 118 and a battery 120 as a battery are accommodated therein. The microcomputer 118 controls a portion other than the detection unit 10 in FIG. 1, that is, corresponds to the processing unit 12 shown in FIG. The battery 120 is a coin-type battery and is replaced when it is exhausted. Of course, a rechargeable battery may be used.

  According to the portable survey system shown in FIG. 13, it is possible to narrow down the contamination source step by step while grasping the system with one hand and referring to the flying direction determined by the hand. That is, the operator can identify the contamination source while moving. In this case, the direction in which the operator moves can be easily specified by the orientation marker 108.

  In the configuration example shown in FIG. 13, three semiconductor sensors are provided instead of the three scintillator members, but in such a configuration, the filter member 118 similar to the filter member shown in FIG. 1 and the like is used. Therefore, different horizontal directivity characteristics can be generated in the respective semiconductor sensors, and the incident direction of radiation can be easily specified by using a response function or the like using such a relationship. However, since the sensitivity of the semiconductor sensor differs depending on the orientation of the semiconductor sensor, it is desirable to create a response function in advance in consideration of such circumstances.

  DESCRIPTION OF SYMBOLS 10 Detection unit, 12 Processing unit, 14, 16, 18 Detection probe, 20 Filter member, 22, 24, 26 Signal processing part, 32 Main calculating part, 34 Main control part, 36 Memory (response function group).

Claims (7)

A detection unit comprising: a plurality of sensors for detecting radiation; and a filter member in which the plurality of sensors are embedded, the member filtering the radiation .
An arithmetic unit for estimating the direction of radiation radiation based on a plurality of measured values measured using the plurality of sensors;
Including
The filter member has a peripheral region as a region closer to the side peripheral surface of the filter member than the center of the filter member;
Wherein the plurality of sensors before Kihen along the side peripheral surface an edge region is housed within a plurality of cavities arranged while spaced apart from each other, thereby each other in their respective of said plurality of sensors A radiation measuring apparatus characterized in that different horizontal directivity characteristics occur. The apparatus of claim 1.
Each of the plurality of sensors is constituted by a scintillator member,
The radiation measuring apparatus according to claim 1, wherein the filter member is formed of a member having a radiation transmission characteristic equivalent to that of the scintillator member. The apparatus according to claim 1 or 2,
The radiation measuring apparatus, wherein the plurality of cavities are respectively inscribed or close to a side peripheral surface of the filter member. The apparatus of claim 2.
Multiple detection probes are used,
Each detection probe includes the scintillator member, a photomultiplier tube that receives light generated by the scintillator member, and a probe case that houses the scintillator member and the photomultiplier tube,
Each of the cavities is configured as a non-penetrating recess connected to the lower surface or the upper surface of the filter member,
In each of the detection probes, a tip portion containing the scintillator member is inserted into each of the recesses,
A radiation measuring apparatus characterized by that. The apparatus according to any one of claims 1 to 4,
Furthermore, the display unit is provided on the upper surface side of the detection unit, and includes a display device having a display surface facing upward.
The radiation measuring apparatus, wherein the radiation direction of the radiation is displayed on the display surface. The apparatus of claim 5.
The radiation measurement apparatus, wherein an orientation display origin on the display surface is located on a vertical center axis of the detection unit.   The survey system comprised as a mobile body or a portable body provided with the radiation measuring device of any one of Claims 1 thru | or 6.

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