JP6524484B2 - Radiation measurement method and radiation measurement apparatus - Google Patents
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- 238000005259 measurement Methods 0.000 title claims description 133
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Description
本発明は、放射線計測方法及び放射線計測装置に関する。 The present invention relates to a radiation measurement method and a radiation measurement apparatus.
自然界には天然の放射性核種（以下、「天然核種」という）が存在しており、また、地域によっては原子力発電所の事故等に伴う人工放射性核種（以下、「人工核種」という）が存在する場所もある。 Natural radionuclides (hereinafter referred to as "natural nuclides") exist in the natural world, and in some regions, artificial radionuclides (hereinafter referred to as "artificial nuclides") are present in some places such as accidents at nuclear power plants. There is also a place.
放射性物質の汚染管理では、汚染管理対象の放射性物質（以下、「管理対象放射性物質」という）のみをそれ以外の放射性物質（天然核種や原発事故起因の人工核種など）と区別して評価することが必要である。管理対象物質を他の放射性物質と区別して計測する方法として、放射線計測機器にエネルギー弁別技術を適用したり、天然核種の減衰を待ってから計測したりするなどしてきたが、エネルギー弁別技術では、天然核種の影響を完全に無くすことはできず、また、天然核種の減衰を待つ方法では、その放射能にもよるが、３日程度の長時間を要している。 In contamination control of radioactive materials, it is possible to evaluate only radioactive materials subject to pollution control (hereinafter referred to as “controlled substance radioactive materials”) separately from other radioactive substances (natural nuclide and artificial nuclide caused by nuclear accident etc.) is necessary. Energy discrimination technology has been applied to radiation measurement equipment as a method of measuring substances to be managed separately from other radioactive substances, or it has been measured after attenuation of natural nuclides, etc. However, with energy discrimination technology, The effects of natural nuclides can not be completely eliminated, and the method of waiting for the decay of natural nuclides requires a long time of about 3 days, depending on the radioactivity.
例えば、プルトニウムなどのα線放出核種の汚染管理において、表面障壁型Ｓｉ半導体検出器によるα線エネルギー弁別を適用した場合は、測定試料の状態にもよるが、放射線管理用ろ紙に放射性物質を集塵した場合、放射線計測上では７割程度しか天然核種の計数を除去することができない。更に、ダストモニタで連続モニタリング（空気汚染の監視）を行う場合には、ダストモニタ指示値には天然核種による計数が含まれているため、その計数値変動によって誤警報が吹鳴しないように警報基準設定値を高めに設定しなければならず、数ベクレル程度の軽微な汚染を検出することが困難である。 For example, when α-ray energy discrimination using a surface barrier type Si semiconductor detector is applied to contamination control of α-ray emitting nuclides such as plutonium, radioactive materials are collected on a filter paper for radiation control although it depends on the state of the measurement sample. In the case of dust, only about 70% can be removed from counting of natural nuclides in radiation measurement. Furthermore, when performing continuous monitoring (monitoring of air pollution) with the dust monitor, the dust monitor indication value includes counting by natural nuclides, so alarm criteria do not sound a false alarm due to the fluctuation of the count value. The set value must be set high, and it is difficult to detect slight contamination of about several beckerels.
昨今では、α線とβ線の放出タイミングを統計的に解析しながら天然核種による計数を取り除く「時間間隔解析技術」を取り入れたモニタリング技術などの新技術の開発が進められているが、計数データの統計処理が必要であるために、計数率（∝放射能）が低い場合には、放射能汚染の有無の判定に長時間を要することがある。 Recently, development of new technologies such as monitoring technology incorporating “time interval analysis technology” that removes counting by natural nuclides while statistically analyzing the emission timing of α rays and β rays has been promoted. In the case where the counting rate (∝ radioactivity) is low, it may take a long time to determine the presence or absence of radioactive contamination, since statistical processing of
一方で、測定計測試料中では、天然核種が全面に均一に分布しているのに対し、管理対象放射性物質は局所的に分布することを利用して、放射能汚染の有無を判定する技術も利用されている。この技術には、オートラジオグラフィやイメージングプレートが用いられるが、これらは放射線の数を計数するのではなく、放射線によって受けたエネルギー量を蓄積して評価するものであり、また、イメージングプレートにおいてはフェーディングの影響もあるため、放射能（1秒間当たりの壊変数）の評価が難しく、放射線計測（放射線
計測装置）への適用は不向きである。
On the other hand, in the measurement sample, natural nuclide is distributed uniformly over the entire surface, while the radioactive substance to be managed is distributed locally, which is a technology to determine the presence or absence of radioactive contamination as well. It's being used. Although autoradiography and imaging plates are used in this technique, they do not count the number of radiation, but accumulate and evaluate the amount of energy received by the radiation, and in imaging plates, Because there is also the effect of fading, it is difficult to evaluate the radioactivity (destruction variables per second), and its application to radiation measurement (a radiation measurement apparatus) is unsuitable.
従来の放射線計測方法及び計測装置は、管理対象放射性物質とそれ以外の放射性物質が混在する環境において、管理対象放射性物質に由来する放射線を短時間に計測して評価することが困難である。 The conventional radiation measuring method and measuring apparatus have difficulty in measuring and evaluating radiation derived from the radioactive substance to be managed in a short time in an environment where the radioactive substance to be managed and other radioactive substances coexist.
本発明の１つの目的は、環境中に管理対象放射性物質とそれ以外の放射性物質が混在する場合であっても、管理対象放射性物質に起因する放射能汚染を短時間に計測して評価することができる放射線計測方法及び放射線計測装置を実現することにある。 SUMMARY OF THE INVENTION One object of the present invention is to measure and evaluate radioactive contamination caused by a radioactive substance to be managed in a short time even when radioactive substances to be managed and other radioactive substances are mixed in the environment. Radiation measurement method and radiation measurement apparatus capable of
本発明の他の目的は、環境中に管理対象放射性物質とそれ以外の放射性物質が混在する場合であっても、管理対象放射性物質に起因する数ベクレル程度の放射能汚染を短時間に計測して評価することにより、作業員に対する早期退避指示や作業の安全性確保を指示することができる放射線計測方法及び放射線計測装置を実現することにある。 Another object of the present invention is to measure radioactive contamination of a few becquerels in a short time due to the radioactive substance to be managed even when the radioactive substance to be managed and other radioactive substances are mixed in the environment. It is an object of the present invention to realize a radiation measurement method and a radiation measurement apparatus capable of instructing workers to perform an early evacuation instruction and ensuring the safety of work by performing evaluation.
本発明の更に他の目的は、管理対象放射性物質に起因する汚染原因の推定や対策の検討が早い段階で行えるようにすることを可能にする放射線計測方法及び放射線計測装置を実現することにある。 Still another object of the present invention is to realize a radiation measurement method and a radiation measurement apparatus which make it possible to estimate the cause of contamination caused by the radioactive substance to be managed and to study the countermeasure at an early stage. .
本発明は、管理対象放射性物質と、前記管理対象放射性物質以外の放射性物質とを含む塵埃を捕集することで得られた集塵ろ紙やスミヤろ紙などの測定試料に対向させることにより該測定試料に付着している放射性物質に感応して検出信号を発生する多数の検出ピクセルを平面状に並べて放射線検出面を構成した放射線検出器の前記多数の検出ピクセルから出力される検出信号を、前記放射線検出面を複数の領域に分割して各分割領域に該当する検出ピクセルから出力される検出信号を検出処理し、分割領域毎に検出される放射線検出結果を出力することができる放射線計測装置を用いて該測定試料中の放射性物質の放射線量を計測する放射線計測方法において、分割領域毎に検出される放射線検出結果では、前記管理対象放射性物質による放射線量の分布と、前記管理対象放射性物質以外の放射性物質による放射線量の分布とが異なることに基づいて、前記管理対象放射性物質による放射線量を計測することを特徴とする放射線計測方法及び放射線計測装置である。
また、本発明は、前記放射線検出面の領域分割は、放射線検出面の領域分割数を変えて放射線検出処理を行って各領域分割数における放射線検出結果を出力表示し、出力表示された放射線検出結果を参照して目的とする放射線計測に好ましい分割領域の数を設定して放射線計測を行うことを特徴とする。
The present invention relates to a measurement sample such as dust collection filter paper or smear filter paper obtained by collecting dust containing a radioactive substance to be managed and a radioactive substance other than the radioactive substance to be managed. The radiation detection signal output from the plurality of detection pixels of the radiation detector in which the radiation detection surface is configured by arranging a large number of detection pixels that generate detection signals in response to radioactive substances attached to the radiation. Using a radiation measurement apparatus capable of dividing the detection surface into a plurality of areas, detecting the detection signal output from the detection pixel corresponding to each divided area, and outputting the radiation detection result detected for each divided area Te in the radiation measuring method for measuring a radiation dose of radioactive material of the measurement sample, in the radiation detection results detected in each divided region, by the managed radioactive materials And ray amount of the distribution, the management target radiation resistance and radiation dose distribution with radioactive materials other than materials based on are different, the radiation measuring method and radiation measurement, characterized in that to measure the radiation amount by the managed radioactive materials It is an apparatus.
Further, according to the present invention, the radiation detection processing is performed by changing the number of divided regions of the radiation detection surface and performing radiation detection processing to output and display the radiation detection result for each number of region division. It is characterized in that radiation measurement is performed by setting the number of division regions preferable for target radiation measurement with reference to the result.
本発明は、放射線検出器の放射線検出面を任意に領域分割（区分）して分割領域毎に検出信号を検出処理して測定試料中の放射性物質の放射能分布を計測することにより、環境中に管理対象放射性物質とそれ以外の放射性物質が混在する場合であっても、管理対象放射性物質に起因する放射能汚染を短時間に計測して評価することができる放射線計測方法及び放射線計測装置を実現することができる。 According to the present invention, the radiation detection surface of the radiation detector is arbitrarily divided (segmented), detection processing of detection signals is performed for each divided region, and the radioactive distribution of radioactive substances in the measurement sample is measured, whereby the environment is obtained. A radiation measurement method and a radiation measurement apparatus capable of measuring and evaluating radioactive contamination caused by the radioactive substance to be managed in a short time even if the radioactive substance to be managed and other radioactive substances are mixed. It can be realized.
本発明は、更に、放射線検出面の領域分割数を計測目的に応じて設定することにより、環境中に管理対象放射性物質とそれ以外の放射性物が混在する場合であっても、管理対象放射性物質に起因する数ベクレル程度の低レベルの放射能汚染を短時間に計測して評価することにより、作業員に対する早期退避指示や作業の安全性確保を指示することができる放射線計測方法及び放射線計測装置を実現することができる。 Further, according to the present invention, by setting the number of area divisions of the radiation detection surface according to the measurement purpose, even if the radioactive substance to be managed and the radioactive substance other than the radioactive substance are mixed in the environment, the radioactive substance to be managed is Radiation measurement method and radiation measurement apparatus capable of instructing workers to perform early evacuation instructions and ensuring the safety of work by measuring and evaluating low level radioactive contamination of about several beckerels caused in a short time Can be realized.
本発明は、更に、放射線検出面の領域分割数を計測目的に応じて設定することにより、管理対象放射性物質に起因する汚染原因の推定や対策の検討が早い段階で行えるようにすることを可能にする放射線計測方法及び放射線計測装置を実現することができる。 The present invention further enables setting of the number of area divisions of the radiation detection surface according to the measurement purpose, so that estimation of the cause of contamination caused by the radioactive substance to be managed and examination of countermeasures can be performed at an early stage. The radiation measurement method and the radiation measurement apparatus according to
本発明の放射線計測方法及び放射線計測装置は、測定試料に対向させることにより該測定試料に付着している放射性物質に感応して検出信号を発生する多数の検出ピクセルを平面状に並べて放射線検出面を構成した放射線検出器の前記多数の検出ピクセルから出力される検出信号を、前記放射線検出面を複数の領域に分割して各分割領域に該当する検出ピクセルから出力される検出信号を検出処理し、分割領域毎に検出される放射線検出結果を出力することができる放射線計測装置を用いて測定試料中の放射性物質の放射能を計測するものであり、
前記放射線検出面の領域分割は、放射線検出面の領域分割数を変えて放射線検出処理を行って各領域分割数における放射線検出結果を出力表示し、出力表示された放射線検出結果を参照して目的とする放射線計測に好ましい分割領域の数を設定して放射線計測を行うものである。
The radiation measurement method and the radiation measurement apparatus according to the present invention arrange a plurality of detection pixels, which are sensitive to radioactive substances adhering to the measurement sample to generate a detection signal by making the measurement sample face the radiation detection plane. Detection signals output from the plurality of detection pixels of the radiation detector configured, the radiation detection surface is divided into a plurality of areas, and detection signals output from detection pixels corresponding to the respective divided areas are detected and processed. Measuring the radioactivity of radioactive substances in the measurement sample using a radiation measuring device capable of outputting a radiation detection result detected for each divided area;
In the area division of the radiation detection surface, the number of area divisions of the radiation detection surface is changed to perform the radiation detection processing, the radiation detection result in each area division number is output and displayed, and the output is displayed with reference to the radiation detection result The radiation measurement is performed by setting the number of division regions preferable for the radiation measurement to be performed.
放射能汚染管理において、管理対象放射性物質と、管理対象放射性物質が発生する放射線の計測において妨害因子となる放射線を発生する天然核種等は、測定試料上に付着する物質の分布が異なり、図１に示すように、前者は放射性物質１ｂが測定試料１ａ上に局所的に存在（ａ）するのに対し、後者は放射性物質１ｃが測定試料１ａ上の全面に均一に存在（ｂ）している。本発明は、この分布の違いを利用した汚染管理・計測技術である。 For radioactive contamination control, the radioactive substance to be managed and the natural nuclide that generates radiation that becomes an interfering factor in the measurement of the radiation generated by the radioactive substance to be managed differ in the distribution of the substance adhering to the measurement sample, As shown in the figure, while the radioactive substance 1b is locally present on the measurement sample 1a (a), the latter is uniformly present on the entire surface of the measurement sample 1a (b). . The present invention is a contamination control and measurement technology using this difference in distribution.
本発明の放射線計測方法で使用する放射線計測装置は、図２に示すように、測定試料に付着している放射性物質が発生する放射線に感応して該放射線に相応する検出信号を出力する放射線検出器２と、この放射線検出器２から出力する検出信号を処理する複数種類の信号処理機能を有する信号処理装置３と、この信号処理装置３に対して特定の信号処理機能の実行を選択的に指示する指示入力器４と、前記信号処理装置３による信号処理状況及び信号処理（検出）結果を出力（表示、印刷、データ保存など）する出力器５を備える。 The radiation measuring apparatus used in the radiation measuring method of the present invention, as shown in FIG. 2, is a radiation detection that responds to radiation generated by radioactive substances adhering to the measurement sample and outputs a detection signal corresponding to the radiation. And a signal processing device 3 having a plurality of types of signal processing functions for processing detection signals output from the radiation detector 2, and selectively performing execution of a specific signal processing function with respect to the signal processing device 3. It includes an instruction input unit 4 for instructing, and an output unit 5 for outputting (displaying, printing, storing data, etc.) the signal processing status and the signal processing (detection) result by the signal processing device 3.
前記放射線検出器２は、測定試料に対向させることにより該測定試料に付着している放射性物質が発生する放射線に感応して検出信号を発生する多数の検出ピクセルを平面状に並べて放射線検出面を構成し、前記多数の検出ピクセルがそれぞれ感応した放射線量に応じた検出信号をそれぞれ出力するように構成する。具体的には、図３に示すように、測定試料に対向して該測定試料に付着している放射性物質が発生する放射線に感応して発光する感応面を形成するシンチレータ２ａと、感応面を形成するシンチレータ２ａに対向するように並べて設置されて該シンチレータ２ａの発光を電気信号（検出信号）に変換する多数の光電素子２ｂと、シンチレータ２ａの発光を該発光位置に対向して位置する光電素子２ｂに伝達する光ガイド２ｃと、シンチレーション光以外の外光が光電素子２ｂに入力しないように遮光する遮光膜２ｄと、光電素子２ｂが発生する検出信号を信号処理装置３に出力する信号出力回路２ｅを備える。前記信号出力回路２ｅは、光電素子２ｂが発生する
検出信号を出力するが、前記検出信号は前記シンチレータ２ａの発光位置に相応する位置情報を有する。
The radiation detector 2 arranges a plurality of detection pixels, which generate detection signals in response to radiation generated by a radioactive substance attached to the measurement sample by facing the measurement sample, to form a radiation detection surface. The plurality of detection pixels are configured to respectively output detection signals according to the radiation dose respectively sensed. Specifically, as shown in FIG. 3, a scintillator 2a that forms a sensitive surface that emits light in response to radiation generated by a radioactive substance that is attached to the measurement sample, facing the measurement sample; A large number of photoelectric elements 2b arranged side by side so as to face the scintillator 2a to be formed and converting the light emission of the scintillator 2a into an electric signal (detection signal), and photoelectrics positioned so as to oppose the light emission position of the scintillator 2a A light guide 2c for transmitting to the element 2b, a light shielding film 2d for shielding external light other than scintillation light from being input to the photoelectric element 2b, and a signal output for outputting a detection signal generated by the photoelectric element 2b to the signal processing device 3 A circuit 2e is provided. The signal output circuit 2e outputs a detection signal generated by the photoelectric element 2b. The detection signal has position information corresponding to the light emitting position of the scintillator 2a.
ここで、α線やβ線を検出可能な放射線検出器２とするためには、前記遮光膜２ｄはα線やβ線を遮へいしないように極めて薄い膜とすることが望ましい。 Here, in order to make the radiation detector 2 capable of detecting α rays and β rays, it is desirable that the light shielding film 2 d be an extremely thin film so as not to block the α rays and β rays.
ここで、前記光電素子２ｂは、既知の位置有感型光電子増倍管（PSPMT；Position Sensitive Photo-Multiplier Tubes）や半導体素子（Si-PMT）等を用いて実現する。 Here, the photoelectric device 2b is realized using a known position sensitive photomultiplier tube (PSPMT), a semiconductor device (Si-PMT) or the like.
また、前記多数の検出ピクセルは、この実施例では、前記シンチレータ２ａと多数の光電素子２ｂと光ガイド２ｃによって構成され、各光電素子２ｂから出力する電気信号が検出信号となり、この検出信号は、前記放射線検出面を複数の領域に分割して各分割領域に対向するように位置する複数の検出ピクセルから出力される検出信号を１つの群として群毎に検出処理することができるようにする。分割領域の大きさは、検出信号の処理による分別も含めて、例えば、放射線検出面を縦８、横８（縦横８×８）に分割した大きさ、縦横１６×１６に分割した大きさ、縦横３２×３２に分割した大きさ、…縦横２５６×２５６に分割した大きさとなるように可変的に設定することができるようにする。 Further, in this embodiment, the large number of detection pixels are constituted by the scintillator 2a, the large number of photoelectric elements 2b and the light guide 2c, and the electric signal output from each photoelectric element 2b becomes a detection signal. The radiation detection surface is divided into a plurality of areas, and detection signals output from a plurality of detection pixels positioned to face each divided area can be detected and processed as one group for each group. The size of the divided area is, for example, a size obtained by dividing the radiation detection surface into 8 vertical and 8 horizontal (8 × 8 vertical), including 16 pixels by 16 horizontal and 16 vertical, including classification by processing of the detection signal. It is possible to variably set the size divided into 32 × 32 in vertical and horizontal directions,..., The size divided into 256 × 256 in vertical and horizontal directions.
この実施例の放射線計測装置では、５ｃｍ×５ｃｍの大きさの放射線検出面の放射線計数分布（２５６×２５６程度の解像度）を信号処理装置３における信号処理上で任意に区画した分割領域毎に纏めることで、最大で装置が有する解像度と同じ数に放射線検出面を分割することができるようにする。 In the radiation measurement apparatus of this embodiment, the radiation count distribution (resolution of about 256 × 256) of the radiation detection surface of 5 cm × 5 cm is collected for each divided area arbitrarily divided on signal processing in the signal processing device 3 This enables the radiation detection surface to be divided up to the same number as the resolution of the device.
図３に示す放射線検出器２おいて、シンチレータ２ａは、１枚の板状のシンチレータ板を用いる構成と、アレイ状のシンチレータ板を用いる構成を想定することができる。１枚板のシンチレータ板を利用する場合には、位置有感型光電子増倍管を使用した光電素子２ｂをシンチレータ２ａに直接接着するとアノードの位置に偏った画像となる。このため、シンチレータ２ａと光電素子２ｂの間に３ｍｍ程度のライトガイド２ｃを設けることにより、画像の偏りを解消するようにすることが望ましい。また、アレイ状のシンチレータ板を使用した場合は、アレイの数が検出面の領域分割数（＝解像度）に等しくなるため、イメージングなど詳細な画像（放射線計測分布）を得るには不向きとなる。 In the radiation detector 2 shown in FIG. 3, the scintillator 2a can assume a configuration using a single plate-like scintillator plate and a configuration using an array-like scintillator plate. In the case of using a single scintillator plate, if the photoelectric element 2b using a position sensitive photomultiplier is directly bonded to the scintillator 2a, an image biased to the position of the anode is obtained. For this reason, it is desirable to eliminate the bias of the image by providing a light guide 2c of about 3 mm between the scintillator 2a and the photoelectric element 2b. When an array-like scintillator plate is used, the number of arrays is equal to the number of area divisions (= resolution) of the detection surface, which makes it unsuitable for obtaining a detailed image (radiation measurement distribution) such as imaging.
更に、この放射線計測装置の利用目的である管理対象放射性物質から発生する放射線と天然核種から発生する放射線との弁別精度を向上させるためには、検出面領域分割（検出位置）に加えてエネルギー弁別機能を付加することが望ましいことから、それが可能なシンチレータを使用することが望ましい。 Furthermore, in order to improve the discrimination accuracy between the radiation generated from the radioactive substance to be managed and the radiation generated from natural nuclide, which is the purpose of using this radiation measurement apparatus, in addition to the detection surface area division (detection position) Because it is desirable to add functionality, it is desirable to use a scintillator capable of that.
エネルギー弁別を行う場合には、計測対象がα線の場合は、エネルギースペクトルが線スペクトルとなることから弁別が比較的容易であるが、β線の場合には連続スペクトルであり、最大エネルギーでの弁別となることから弁別精度は悪く、弁別できるのは90Ｙ（イットリウム）から放出されるβ線などのように高エネルギーのβ線に限定される。 When energy discrimination is performed, when the measurement target is an alpha ray, the energy spectrum is a line spectrum, so discrimination is relatively easy, but in the case of a beta ray, it is a continuous spectrum and the maximum energy Discrimination accuracy is poor because of discrimination, and discriminability is limited to high energy beta rays such as beta rays emitted from 90 Y (yttrium).
放射線検出面の領域分割については、複数の放射線検出器を並べて各放射線検出器の放射線検出面を１つの分割領域とする構成でもよく、また、検出信号処理上で検出信号の位置情報に基づいて分割領域を特定することが可能な放射線検出器を用いて実現する構成でもよい。また、放射線の検出原理は、シンチレーション検出器や半導体検出器などに限定されるものではない。 Regarding area division of the radiation detection surface, a configuration may be adopted in which a plurality of radiation detectors are arranged to make the radiation detection surface of each radiation detector into one divided region, and on detection signal processing based on position information of detection signals. It may be realized by using a radiation detector capable of specifying the divided area. Moreover, the detection principle of radiation is not limited to a scintillation detector or a semiconductor detector.
前記信号処理装置３は、プロセッサと複数種類の信号処理プログラムを組み合わせて複数種類の信号処理機能を選択的に実現することができるように構成され、信号出力回路２
ｅを介して光電素子２ｂから入力した検出信号をその位置情報と波高値を有する検出データに変換処理し、この検出データを処理して測定試料における放射線検出位置と検出波高値の算出及び図形表示編集等を行う。例えば、特定の分割領域に属する検出データを集計して該分割領域に存在する放射性物質が発生する放射線量を示す棒グラフを作成して表示する処理を行う。
The signal processing device 3 is configured to be able to selectively realize a plurality of types of signal processing functions by combining a processor and a plurality of types of signal processing programs, and a signal output circuit 2
The detection signal input from the photoelectric element 2b through e is converted into detection data having the position information and the peak value, and the detection data is processed to calculate the radiation detection position and the detection peak value on the measurement sample and display the figure Edit etc. For example, processing is performed to totalize detection data belonging to a specific divided area and create and display a bar graph indicating the radiation dose generated by the radioactive substance present in the divided area.
指示入力器４は、オペレータにより操作され、信号処理装置３が所定の信号処理機能を実現するように実行する信号処理プログラムの選択を指示入力する。 The instruction input unit 4 is operated by the operator and inputs a selection of a signal processing program to be executed by the signal processing device 3 to realize a predetermined signal processing function.
このような構成の放射線計測装置は、信号処理装置３において、検出位置情報（放射線検出面の領域分割数は任意）を有した放射線検出データ（計数値）を作成し、この検出データを任意の形態で表示・保存する複数種類の信号処理機能を選択的に設定して実行する。例えば、放射線検出データを作成する信号処理機能では、放射線検出面の領域分割数、検出信号弁別波高値、検出信号計数時間、検出信号計数間隔等の計測条件を指示入力器４からの入力によって任意に設定または選択設定して信号処理することを可能にし、検出データを表示・保存する信号処理機能では、数表図形、棒グラフ図形（２次元棒グラフまたは３次元棒グラフ）、折れ線グラフ図形等の表示・保存条件を指示入力器４からの入力によって任意に設定または選択設定して処理することを可能に構成する。 In the radiation measuring apparatus having such a configuration, in the signal processing apparatus 3, radiation detection data (count value) having detection position information (the number of area divisions of the radiation detection surface is arbitrary) is created, and this detection data is Selectively set and execute multiple types of signal processing functions to be displayed and stored in a form. For example, in the signal processing function that creates radiation detection data, measurement conditions such as the number of area divisions of the radiation detection surface, detection signal discrimination peak value, detection signal counting time, detection signal counting interval, etc. In the signal processing function that enables signal processing to be set or selected and displayed and saves detected data, display of several figures, bar graphs (two-dimensional bar graphs or three-dimensional bar graphs), line graph graphics, etc. The storage conditions can be arbitrarily set or selected and processed by the input from the instruction input unit 4.
このような検出面分割型の放射線計測装置を用いて、局所的に検出される放射線を計測することによって、管理対象放射性物質に着目した評価が容易に可能となる。 By measuring the radiation detected locally using such a detection surface division type radiation measurement apparatus, an evaluation focusing on the radioactive substance to be managed becomes easily possible.
従来の放射線計測装置は、放射線検出面を分割する形態で検出信号を処理していないことから、均一に分布する管理対象放射性物質以外の放射性物質（天然核種等）から発生する放射線も全て一括して検出してしまうが、この実施例の放射線計測装置では、天然核種から発生する放射線の計数が放射線検出面の領域分割数に応じて分散されることから、その計数値を低く抑えることが可能である。これに対して、管理対象放射性物質から発生する放射線は付着部位が局部的に高くなることから、対応する分割領域において集中的に計測され、放射線検出面の領域分割を行っても付着部位に対向する分割領域における計数値の低下は少ないので、目的とする放射線の計測は支障なく実現することができる。 The conventional radiation measurement apparatus does not process the detection signal in a form of dividing the radiation detection surface, so all radiation generated from radioactive substances (natural nuclide etc.) other than the management target radioactive substance distributed uniformly is also collectively However, in the radiation measurement apparatus of this embodiment, since the counts of radiation generated from natural nuclides are dispersed according to the number of area divisions of the radiation detection surface, it is possible to keep the count value low. It is. On the other hand, the radiation generated from the radioactive substance to be managed is locally measured in the corresponding divided area because the adhesion area is locally high, and even if the area division of the radiation detection surface is performed, it faces the adhesion area Since the decrease in the count value in the divided area to be divided is small, measurement of the target radiation can be realized without any problem.
放射線検出面の適切な領域分割数については、計測環境によって異なることから、計測環境に応じて変更することができるように構成する。また、測定時間の単位（１分、２分…）についても、短いほど迅速に汚染検出が可能となるが、一方では、計測時間を短くすると計数値が小さくなって信頼性が落ちることになるので、計測環境と計測目的に応じて変更することができるように構成する。 The appropriate number of area divisions of the radiation detection surface is configured to be able to be changed according to the measurement environment because it varies depending on the measurement environment. In addition, the shorter the measurement time unit (1 minute, 2 minutes ...), the faster the contamination can be detected, but on the other hand, if the measurement time is shortened, the count value becomes smaller and the reliability decreases. Therefore, it is configured to be able to change according to the measurement environment and the purpose of measurement.
図４は、放射線検出器２の放射線検出面を１４４（１２×１２）の領域に分割した場合の検出（計数）例を示す棒グラフである。従来の計測技術では、放射線検出面を領域分割して検出信号を計数処理していないことから、（ａ）に示すように、計数値は２６４カウントという情報のみとなり、僅かに含まれる管理対象放射性物質による放射能汚染の有無を評価することができない（天然核種１ｃから発生する放射線の計数１ｃｎ“２３８カウント”と放射能汚染管理対象の放射性物質１ｂから発生する放射線の計数１ｂｎ“２６カウント”を区別して評価することができない）。
一方、この実施例の計測技術では、（ｂ）に示すように、天然核種１ｃから発生する放射線の１分割領域当りの計数１ｃｎは概ね一様に３カウント程度であるのに対して、測定試料中に混在した２つの人工核種から発生する放射線の１分割領域当りの計数１ｂｎは１８カウント、８カウントとなることから、管理対象放射性物質に由来する放射線とそれ以外の放射性物質に由来する放射線を容易に区別して評価することができる。
FIG. 4 is a bar graph showing an example of detection (counting) when the radiation detection surface of the radiation detector 2 is divided into 144 (12 × 12) regions. In the conventional measurement technology, since the radiation detection surface is not divided into areas and the detection signal is not counted, as shown in (a), the count value is only information of 264 counts, and the radiation for management slightly included It is not possible to assess the presence or absence of radioactive contamination by substances (counting 1cn "238 counts" of radiation generated from natural nuclide 1c and counting 1bn "26 counts" of radiation generated from radioactive substance 1b subject to radioactive contamination control Can not be distinguished and evaluated).
On the other hand, in the measurement technique of this embodiment, as shown in (b), while the count 1 cn per division area of the radiation generated from the natural nuclide 1 c is almost uniformly 3 counts, Since the count 1bn per division area of radiation generated from two artificial nuclides mixed in is 18 counts and 8 counts, radiation derived from the radioactive substance to be managed and radiation derived from other radioactive substances It can be easily distinguished and evaluated.
このように放射線検出面を領域分割して分割領域毎に放射線を計数すると、天然核種などの一様に分布する放射性物質から発生する放射線の計数を低く抑えることが可能になることから、α線放出核種の場合、数ベクレル程度の局所的な放射能汚染であれば、数分間で分別して評価することが可能となる。また、放射線検出面の領域分割数を多く設定すれば、放射線のイメージングが可能となり、放射能汚染物質の存在形態が分かるようになる。但し、イメージングの場合は、放射線検出面の分割領域を細かくする必要があり、その場合には、１分割領域当りの計数率が低くなることから、計測時間を長くすることが必要となる。 As described above, when the radiation detection surface is divided into areas and the radiation is counted for each divided area, it is possible to suppress the counting of radiation generated from uniformly distributed radioactive substances such as natural nuclide, so that α rays In the case of emitted radionuclides, local radioactive contamination of about several becquerels can be separated and evaluated in a few minutes. In addition, if the number of area divisions of the radiation detection surface is set to a large number, imaging of radiation becomes possible, and it becomes possible to know the existence form of radioactive contamination. However, in the case of imaging, it is necessary to make the divided areas of the radiation detection surface finer, and in that case, since the count rate per divided area becomes low, it is necessary to extend the measurement time.
放射線検出面の適切な領域分割数については、適用する放射線計測によって異なる。以下、検出面の全体の大きさを５ｃｍ角とした場合について述べる。 The appropriate number of area divisions of the radiation detection surface varies depending on the radiation measurement to be applied. Hereinafter, the case where the entire size of the detection surface is 5 cm square will be described.
例えば、放射能測定装置やダストモニタのように、測定試料と放射線検出器の放射線検出面の間に５ｍｍ程度の空間が生じる第１の仕様例では、測定試料から放出される放射線は放射線検出面に到達するまでに広がりを持ってしまうことから、放射線検出面を細かく分割しても意味がない。この第１の仕様例の場合は、６４分割（８×８）（＝１つの分割領域は６ｍｍ角）程度が適した領域分割数となる。 For example, in the first specification example in which a space of about 5 mm is generated between the measurement sample and the radiation detection surface of the radiation detector, such as a radioactivity measuring device or dust monitor, radiation emitted from the measurement sample is a radiation detection surface There is no point in finely dividing the radiation detection surface because it has a spread until it reaches. In the case of the first specification example, the number of area divisions is about 64 divided (8 × 8) (one divided area is 6 mm square) or so.
一方、測定試料中に含まれる放射能汚染物質の有無を迅速に検出したい第２の仕様例では、２５６分割（１６×１６）（＝１つの分割領域は３ｍｍ角）又は１，０２４分割（３２×３２）（＝１つの分割領域は１．６ｍｍ角）程度が適している。 On the other hand, in the second specification example where it is desired to quickly detect the presence or absence of radioactive contaminants contained in the measurement sample, 256 divisions (16 × 16) (one division area is 3 mm square) or 1,024 divisions (32) × 32) (1 divided area is about 1.6 mm square) is suitable.
更に、放射能分布のイメージングを行う第３の仕様例では、計測装置の位置分解能に応じた放射線検出面の領域分割数が必要であり、１６，３８４分割（１２８×１２８）（＝１つの分割領域は０．４ｍｍ角）程度が適している。但し、第２及び第３の仕様例の場合は、測定試料と放射線検出面を密着させて測定する構成であることが必要であり、放射能汚染拡大防止のために、測定試料又は放射線検出面を養生する必要がある。 Furthermore, in the third specification example for imaging the radiation distribution, the number of area divisions of the radiation detection plane according to the position resolution of the measurement device is necessary, and 16,384 divisions (128 × 128) (one division) The area is suitably about 0.4 mm square). However, in the case of the second and third specification examples, it is necessary to have a configuration in which the measurement sample and the radiation detection surface are in close contact with each other and measurement is performed. Need to be cured.
次に、第１の仕様例から第３仕様例に示した手法について、具体例を説明する。 Next, specific examples of the methods shown in the first specification example to the third specification example will be described.
第１の仕様例（放射線検出面と測定試料との間に５ｍｍ程度の空間が生じる場合）の具体例として、ダストモニタに適用した場合の放射能汚染検知方法について説明する。 A radioactive contamination detection method applied to a dust monitor will be described as a specific example of the first specification example (when a space of about 5 mm is generated between the radiation detection surface and the measurement sample).
図５は、ダストモニタを用いて空気中の塵埃をろ紙に捕集しながらα線を２分間隔で計測したデータの折れ線グラフであり、ろ紙上には天然核種が約４０Ｂｑ（ベクレル）程度付着している状態である。また、α線放出核種の放射能汚染の検出を再現するため、これとは別に計測した約１．２Ｂｑ程度のプルトニウム試料の計測データを途中（１５：００から）から足し合わせている。 FIG. 5 is a line graph of data obtained by measuring alpha rays at intervals of 2 minutes while collecting dust in the air on a filter using a dust monitor, and about 40 Bq (becquerel) of natural nuclides adhered on the filter It is in the state of doing. Also, in order to reproduce the detection of radioactive contamination of α-ray emitting nuclides, measurement data of about 1.2 Bq of plutonium samples separately measured from this are added from the middle (from 15:00).
従来技術によるダストモニタ指示値では、ろ紙全体を測定（計数）しているために、僅かな指示値上昇の原因が天然核種の変動なのか、放射能汚染物質であるプルトニウムが新たに付着したのかを判別することができないことが分かる。 Since dust monitor readings according to the prior art measure (count) the entire filter paper, may the slight increase in readings be caused by fluctuations in natural nuclides, or may radioactive contamination plutonium be newly attached? It can be seen that it can not be determined.
一方、本発明を適用したダストモニタの場合（図５では放射線検出面の領域を６４分割している）、放射線検出面を分割することによりデータ数は増えるが、天然核種の計数はいずれも低い値（３カウント程度）で一定している。ここに約１．２Ｂｑのプルトニウムが付着した場合には、付着部位に対向する付近の複数の分割領域の検出ピクセルでプルトニウムからのα線を計数するが、最も高く検出する検出部位（分割領域）で１０カウント程度の計数（天然核種を合わせると１３カウント程度）があり、プルトニウム汚染が発生したことを容易に区別して検出できることが分かる。 On the other hand, in the case of the dust monitor to which the present invention is applied (the region of the radiation detection surface is divided into 64 in FIG. 5), the number of data increases by dividing the radiation detection surface, but the counts of natural nuclides are low It is constant at the value (about 3 counts). Here, when about 1.2 Bq of plutonium is attached, the alpha rays from plutonium are counted at detection pixels of a plurality of divided areas in the vicinity facing the attached area, but the detected area (division area) detected the highest It can be seen that there are about 10 counts (about 13 counts when natural nuclides are combined), and that plutonium contamination can be easily distinguished and detected.
また、本発明を適用したダストモニタでの放射能汚染検出方法としては、基本的には各放射線検出面で一律に警報設定値を定めて行うのが簡易的で分かりやすいが、より低いレベルの放射能汚染を検出したい場合は、「隣り合う検出部位（分割領域）で同時に検出する」、「連続したデータで警報設定値を超える」などの信号処理条件を付加することにより実現可能となる。 In addition, as a radioactive contamination detection method in the dust monitor to which the present invention is applied, basically, it is simple and easy to understand that the alarm setting value is uniformly determined on each radiation detection surface, but it is easy to understand. When radioactive contamination is desired to be detected, it can be realized by adding signal processing conditions such as “simultaneously detect in adjacent detection sites (divided regions)” and “consecutive data exceeds alarm set value”.
次に、第２の仕様例（測定試料中に含まれる放射能汚染物質を迅速に検出したい場合）の具体例として、ろ紙上の放射能汚染の検出方法について説明する。 Next, a method of detecting radioactive contamination on filter paper will be described as a specific example of the second specification example (when it is desired to quickly detect radioactive contamination contained in a measurement sample).
この第２の仕様例の手法は、第１の仕様例において「汚染のおそれがあると判断された測定試料（集塵ろ紙やスミヤろ紙など）」について、その詳細な計測を実施し、放射能汚染の有無及びその放射能を評価するときなどに使用することができる。この計測では、測定試料に放射線検出器を密着させて計測を行うことにより、より局所的な放射能を計測することができるようになる。しかし、放射能汚染した測定試料に放射線検出器を密着させて計測する際は、計測作業時の放射能汚染の拡大を防ぐために、測定試料又は放射線検出面を養生してから計測を行うようにすることが望ましい。 The method of this second specification example carries out detailed measurement of “measurement samples (dust filter paper, smear filter paper, etc. determined to be at risk of contamination)” in the first specification example, and radioactivity It can be used when evaluating the presence or absence of contamination and its radioactivity. In this measurement, by making the radiation detector in close contact with the measurement sample and performing the measurement, it is possible to measure more local radioactivity. However, when making a radiation detector in close contact with a radioactively-contaminated measurement sample and performing measurement, in order to prevent the spread of radioactive contamination during the measurement operation, cure the measurement sample or the radiation detection surface before performing measurement. It is desirable to do.
図６は、放射能が約５０Ｂｑの天然核種（ラドン子孫核種）と、放射能が１Ｂｑの管理対象放射性物質（プルトニウム）がろ紙上に存在する測定試料を５分間計測したときの検出信号を放射線検出面の領域分割数を変えて処理したときの検出結果を示す棒グラフである。放射線検出面を細かく領域分割していくと、天然核種の計数が分散されるために管理対象放射性物質による計数がより確認しやすくなるが、過度に細かくすると、管理対象放射性物質の計数値も分割されてしまい、短時間の測定では放射能汚染を発見しにくくなる傾向を呈する。 Fig. 6 shows the detection signal when the measurement sample containing a natural nuclide (Radon progeny nuclide) with a radioactivity of about 50 Bq and a controlled substance with a radioactivity of 1 Bq (plutonium) on a filter paper is measured for 5 minutes It is a bar graph which shows the detection result when the area | region division number of a detection surface is changed and processed. If the radiation detection surface is divided into smaller areas, the counts by the radioactive substance to be managed can be more easily confirmed because the counts of natural nuclides are dispersed, but if it is too fine, the counts of radioactive substances to be managed are also divided It tends to be difficult to detect radioactive contamination in a short time measurement.
図６に例示した検出結果から判断すると、５分程度の計測で放射能汚染の有無を判定する場合は、放射線検出面の領域分割は、１６×１６あるいは３２×３２程度の分割数が適していることになる。但し、適切な領域分割数は、天然核種の濃度等によって異なる（天然核種の濃度が低ければ領域分割数が少なくても識別可能となる）ことから、放射線計測装置は、計測準備段階または計測中に、オペレータに操作される指示入力器４からの指示入力に基いて、放射線検出器の放射線検出面の複数種類の領域分割について各領域分割数での検出結果を出力器５に見本表示し、オペレータが表示見本を観察して計測目的に適切な検出結果が得られる領域分割数を選択的に設定することができるようにする。 Judging from the detection results illustrated in FIG. 6, when determining the presence or absence of radioactive contamination by measurement for about 5 minutes, the division number of about 16 × 16 or 32 × 32 is suitable for area division of the radiation detection surface It will be. However, since the appropriate number of area divisions differs depending on the concentration of natural nuclide and the like (if the concentration of natural nuclide is low, discrimination is possible even if the number of area divisions is small), the radiation measurement device is in the measurement preparation stage or under measurement. Based on the instruction input from the instruction input unit 4 operated by the operator, the detection result in each area division number is sampled and displayed on the output unit 5 with respect to the plurality of types of area division of the radiation detection surface of the radiation detector The operator observes the display sample to selectively set the number of area divisions for which a detection result suitable for the measurement purpose can be obtained.
この手法では、得られた各検出部位（分割領域）の計数値と検出効率から放射能の評価が可能となるだけでなく、計数値分布から大まかな放射能汚染の広がり状況を把握することができるため、汚染状況の把握や汚染原因の推定など、その後の対応に役立てることができる情報を一度に得ることができる。 With this method, it is possible not only to be able to evaluate the radioactivity from the count value and detection efficiency of each detection site (divided area) obtained, but also to grasp the spread situation of the radioactive contamination roughly from the count value distribution. As a result, it is possible to obtain information that can be used for subsequent responses, such as understanding of the contamination status and estimation of the cause of contamination at one time.
第３の仕様例（放射能分布のイメージングを行う場合）は、第２の仕様例で得られた計数分布を更に詳しく調査する際の手法として実行することができる。計測方法自体は第２の仕様例と同じであるが、より詳細な分布を計測するためには、放射線検出面の領域分割をできるだけ細かくすることが望ましい。 The third specification example (when imaging the activity distribution) can be implemented as a method for examining the count distribution obtained in the second specification example in more detail. Although the measurement method itself is the same as in the second specification example, in order to measure a more detailed distribution, it is desirable to make the area division of the radiation detection surface as fine as possible.
図３に示した放射線検出器２の場合は、固有分解能は０．８ｍｍ程度であるため、領域分割数は１６，３８４分割（１２８×１２８）（＝１つの検出部位は０．４ｍｍ角）ないし６５，５３６分割（２５６×２５６）（＝１つの検出部位は０．２ｍｍ角）が適したものとなる。但し、検出部位１箇所あたりの面積が小さくなると計測での計数値も少なくなるため、詳細分布を得るには長時間の計測が必要となる。図７は、この手法を用いて汚染
試料を計測（２０分間計測）した際の計数分布図である。この図７の分布図形を観察すると、放射能汚染状態（広がり、形状）が分かるとともに、各部位の放射能量も評価することができる。
In the case of the radiation detector 2 shown in FIG. 3, since the intrinsic resolution is about 0.8 mm, the number of area divisions is 16,384 (128 × 128) (one detection site is 0.4 mm square) to The 65,536 division (256 × 256) (one detection site is 0.2 mm square) is suitable. However, if the area per one detection site decreases, the count value in the measurement decreases, so long-time measurement is required to obtain the detailed distribution. FIG. 7 is a count distribution chart when the contaminated sample is measured (measured for 20 minutes) using this method. By observing the distribution diagram of FIG. 7, the radioactive contamination state (spread, shape) can be known, and the amount of radioactivity at each site can also be evaluated.
このような本発明の放射線計測方法及び放射線計測装置は、以下に説明するように、「汚染検査モード」（未知の測定試料に付着している放射性物質の放射線を計測する場合）と「ダストモニタモード」（測定試料に付着している放射能汚染を連続的に監視する場合）の計測モードでの実用化が考えられる。 As described below, such a radiation measuring method and apparatus according to the present invention have a “contamination inspection mode” (in the case of measuring the radiation of a radioactive substance attached to an unknown measurement sample) and a “dust monitor”. Practical application in the measurement mode (when monitoring the radioactive contamination attached to the measurement sample continuously) is conceivable.
汚染検査モード（1回測定モード）
この計測モードは、測定試料中に含まれる人工核種（核燃料物質等の放射性物質）の有無を判断し、その放射能を評価することが可能である。また、一方で、測定試料上に存在する管理対象放射性物質の付着の状況（スポット状に存在、液体が付着したような状態、粉末が飛び散ったような状態など）も確認できるようになる。
Contamination inspection mode (single measurement mode)
In this measurement mode, it is possible to determine the presence or absence of an artificial nuclide (a radioactive substance such as a nuclear fuel substance) contained in a measurement sample, and to evaluate its radioactivity. Also, on the other hand, it is possible to confirm the state of adhesion of the radioactive substance to be managed present on the measurement sample (presence in the form of a spot, a state in which the liquid adheres, a state in which the powder is scattered, etc.).
放射能を評価する場合、主たる計測対象である管理対象放射性物質の形状・放射能と、計測上の妨害因子である天然核種の放射能によって、放射線検出面の適切な領域分割数が異なるため、計測中に放射線検出面の領域分割数を変更しながら計測データ（計数値分布）を確認することで、より迅速に放射能汚染（管理対象放射性物質の付着）の有無を判断することができる。また、同時にエネルギースペクトル（パルス波高分布）を確認し、適切な波高弁別を行うことで、つまり、計測したい放射性物質からの放射線のエネルギーに計測対象を絞ることで、更に放射能汚染の有無の判断時間を短縮することができる。このためには、放射線検出器２にエネルギー弁別が可能なシンチレータを使うのが有効である。 When evaluating radioactivity, the number of appropriate area divisions on the radiation detection surface differs depending on the shape and activity of the radioactive substance to be managed, which is the main measurement target, and the activity of natural nuclides that are interference factors in measurement. By checking the measurement data (count value distribution) while changing the number of area divisions of the radiation detection surface during measurement, the presence or absence of radioactive contamination (adhesion of the radioactive substance to be managed) can be determined more quickly. At the same time, by confirming the energy spectrum (pulse wave height distribution) and performing appropriate wave height discrimination, that is, narrowing the measurement target to the energy of the radiation from the radioactive substance to be measured, it is further judged the presence or absence of radioactive contamination. Time can be shortened. For this purpose, it is effective to use a scintillator capable of energy discrimination as the radiation detector 2.
この計測モードでの実用化の場合、放射線検出面の領域分割数は、概ね３２×３２までで済むが、測定試料上の核燃料物質等の形状を確認する場合（イメージングをする場合）は、より細かい領域分割数が必要となる。ただし、１ピクセルあたりの計測数は激減することから、計測時間を長くすることが必要となる。 In the case of practical use in this measurement mode, the number of area divisions of the radiation detection surface may be approximately 32 × 32, but when confirming the shape of the nuclear fuel material etc. on the measurement sample (when imaging), A fine number of area divisions is required. However, since the number of measurements per pixel decreases drastically, it is necessary to extend the measurement time.
これにより、従来技術である放射線測定装置、スペクトル測定装置、オートラジオグラフィの３つの装置による計測は、この発明の装置１つで対応することができるようになり、放射能管理対応全体の合理化が図れるようになる。 As a result, measurement by the prior art radiation measurement device, spectrum measurement device, and measurement by three devices of autoradiography can be coped with one device of the present invention, and rationalization of the whole radiation management correspondence is possible. It will be possible.
ダストモニタモード（繰り返し測定モード）
この計測モードは、作業環境中の塵埃をろ紙に集塵しながら連続的に該ろ紙上の放射線を計測するモードであり、核燃料物質等がろ紙へ新たに付着するのを発見することによって、管理対象放射性物質による空気汚染を検出するものである。
Dust monitor mode (repeated measurement mode)
This measurement mode is a mode in which the radiation on the filter paper is continuously measured while dusts in the working environment are collected on the filter paper, and management is performed by finding that nuclear fuel substances etc. are newly attached to the filter paper. It detects air pollution by target radioactive materials.
従来技術では、放射線検出面が分割されていないために計測値は１つであるが、本発明技術では、放射線検出面の分割数に応じて計測データの数が多くなる。計測データ数が多くなると、計測値も分散されるので各計測値は減少するが、核燃料物質が付着した領域に対応する分割領域のみは計数値が高いので核燃料物質が付着していることを識別することができ、従来技術に比較して、極めて低いレベルの放射能汚染をも検出することができるようになる。 In the prior art, the radiation detection surface is not divided, and there is only one measurement value. However, in the technique of the present invention, the number of measurement data increases according to the number of divisions of the radiation detection surface. When the number of measured data increases, the measured values are also dispersed, so each measured value decreases. However, because the count value is high only in the divided region corresponding to the region where the nuclear fuel material is attached, it is identified that the nuclear fuel material is attached. It is possible to detect even very low levels of radioactive contamination compared to the prior art.
放射線検出面の適切な領域分割数については、計測環境によって異なることから、計測中に検出面の領域分割数を変更しながら計測データ（計数値分布）を確認することで、より迅速に放射能汚染（核燃料物質の付着）の有無を判断することができる。 Since the appropriate number of area divisions of the radiation detection surface varies depending on the measurement environment, the radioactivity can be determined more quickly by confirming the measurement data (count value distribution) while changing the number of area divisions of the detection surface during measurement. The presence or absence of contamination (adhesion of nuclear fuel material) can be determined.
また、計測時間の単位（１分、２分……）についても、短いほど迅速に放射能汚染の検出が可能となるが、一方では、計数値が小さくなって信頼性が落ちることになるので、必要に応じて変更するようにする。 In addition, the shorter the measurement time unit (1 minute, 2 minutes, etc.), the faster the radioactive contamination can be detected, but on the other hand, the count value becomes smaller and the reliability drops. Make changes as needed.
本発明技術では、放射能の評価も同時に実施することができるように、計数値から放射能量への換算するための「換算係数」を登録又は算出できるようにし、予め求めた換算係数を設定する機能と、線源を複数回測定することによって換算係数（検出効率）が自動的に求められるような機能など、計測装置の校正が行える機能を設けることが望ましい。 In the technology of the present invention, the "conversion factor" for converting the count value into the amount of radioactivity can be registered or calculated so that the evaluation of radioactivity can be performed simultaneously, and the conversion factor obtained in advance is set. It is desirable to provide a function capable of performing calibration of the measuring apparatus, such as a function and a function by which a conversion coefficient (detection efficiency) can be automatically obtained by measuring the radiation source a plurality of times.
１ａ…測定試料 １ｂ…放射性物質 １ｃ…放射性物質 ２…放射線検出器 ２ａ…シンチレータ ２ｂ…光電素子 ２ｃ…光ガイド ２ｄ…遮光膜 ２ｅ…信号出力回路 ３…信号処理装置 ４…指示入力器 ５…出力器。 DESCRIPTION OF SYMBOLS 1a ... Measurement sample 1b ... Radioactive substance 1c ... Radioactive substance 2 ... Radiation detector 2a ... Scintillator 2b ... Photoelectric element 2c ... Light guide 2d ... Light shielding film 2e ... Signal output circuit 3 ... Signal processing apparatus 4 ... Instruction input device 5 ... Output vessel.
Claims (4)
分割領域毎に検出される放射線検出結果では、前記管理対象放射性物質による放射線量の分布と、前記管理対象放射性物質以外の放射性物質による放射線量の分布とが異なることに基づいて、前記管理対象放射性物質による放射線量を計測することを特徴とする放射線計測方法。 It adheres to the measurement sample by facing the measurement sample such as dust collection filter paper or smear filter paper obtained by collecting dust containing the radioactive substance to be managed and radioactive substances other than the radioactive substance to be managed. A plurality of detection signals output from the plurality of detection pixels of the radiation detector in which a plurality of detection pixels that generate detection signals in response to a radioactive substance and generate detection signals are formed into a plurality of radiation detection surfaces The measurement sample is divided into the following areas and the detection signal output from the detection pixel corresponding to each divided area is detected and processed, and the radiation measurement device capable of outputting the radiation detection result detected for each divided area In a radiation measurement method for measuring the radiation dose of radioactive substances in
In the radiation detection result detected for each divided area, the radioactive object to be managed is based on the difference between the distribution of the radiation dose by the radioactive substance to be managed and the distribution of the radiation dose by radioactive substances other than the radioactive substance to be managed A radiation measurement method comprising measuring a radiation dose due to a substance.
分割領域毎に検出される放射線検出結果では、前記管理対象放射性物質による放射線量の分布と、前記管理対象放射性物質以外の放射性物質による放射線量の分布とが異なることに基づいて、前記管理対象放射性物質による放射線量を計測することを特徴とする放射線計測装置。 It adheres to the measurement sample by facing the measurement sample such as dust collection filter paper or smear filter paper obtained by collecting dust containing the radioactive substance to be managed and radioactive substances other than the radioactive substance to be managed. The radiation detector has a radiation detection surface configured by arranging in a plane a large number of detection pixels that generate detection signals in response to radioactive substances, and includes a plurality of types of signal processing functions, and the detection of the plurality of radiation detectors The detection signal output from the pixel is input, and the detection signal output from the detection pixel corresponding to each divided area obtained by dividing the radiation detection surface into a plurality of areas is processed to detect the radiation detection result detected for each divided area A radiation processing apparatus comprising: a signal processing device for outputting a signal processing unit ;
In the radiation detection result detected for each divided area, the radioactive object to be managed is based on the difference between the distribution of the radiation dose by the radioactive substance to be managed and the distribution of the radiation dose by radioactive substances other than the radioactive substance to be managed A radiation measurement apparatus characterized by measuring a radiation dose due to a substance.
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