JPH0350228B2 - - Google Patents
Info
- Publication number
- JPH0350228B2 JPH0350228B2 JP19710681A JP19710681A JPH0350228B2 JP H0350228 B2 JPH0350228 B2 JP H0350228B2 JP 19710681 A JP19710681 A JP 19710681A JP 19710681 A JP19710681 A JP 19710681A JP H0350228 B2 JPH0350228 B2 JP H0350228B2
- Authority
- JP
- Japan
- Prior art keywords
- pulse
- sample
- radioactivity
- radiation detector
- container
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000005855 radiation Effects 0.000 claims description 11
- 238000005259 measurement Methods 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 3
- 238000011002 quantification Methods 0.000 claims 1
- 230000005251 gamma ray Effects 0.000 description 10
- 239000002901 radioactive waste Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000084 gamma-ray spectrum Methods 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 239000012857 radioactive material Substances 0.000 description 1
- 239000000941 radioactive substance Substances 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 239000002915 spent fuel radioactive waste Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/17—Circuit arrangements not adapted to a particular type of detector
- G01T1/171—Compensation of dead-time counting losses
Description
【発明の詳細な説明】
本発明は放射性物質の放射能定量法および装置
に係る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for quantifying radioactivity of radioactive substances.
使用剤核燃料再処理工場など、高レベルの放射
性物質を発生したり、取扱つたりする場所では、
容器に収容した放射性廃棄物等の含有する放射性
核種を分析したり、定量したりすることが必要と
なる。 In places where high levels of radioactive materials are generated or handled, such as used nuclear fuel reprocessing plants,
It is necessary to analyze and quantify radionuclides contained in radioactive waste, etc. stored in containers.
ガンマ線を放出する２種以上の放射性核種を含
む放射性廃棄物を非破壊的に分析、定量するに
は、通常被測定試料の放出するガンマ線のエネル
ギスペクトルを測定することによつている。ガン
マ線のエネルギスペクトルの測定は、パルス型の
放射線検出器（シンチレータやSSD）と、多重波
高分析器（MCA）とを併用して行う。 Radioactive waste containing two or more types of radionuclides that emit gamma rays can be non-destructively analyzed and quantified by normally measuring the energy spectrum of gamma rays emitted by a sample to be measured. The energy spectrum of gamma rays is measured using a combination of a pulsed radiation detector (scintillator or SSD) and a multiple pulse height analyzer (MCA).
而して、例えば放射性廃棄物を収容する容器は
通常円柱状かほぼ円柱状であり、放射性廃棄物は
その不均一に充填されていることが多い。従つ
て、ガンマ線測定による放射能定量を行うには、
ガンマ線コリメータを入射口に有するガンマ線検
出器の前で、容器を軸方向に移動させると共に容
器の軸を中心として回転させ、容器内部から放出
されるガンマ線を平均的に検出するようにして、
不均一な充填状態に基く定量誤差を少くするよう
にしている。 Thus, for example, containers containing radioactive waste are typically cylindrical or nearly cylindrical, and the radioactive waste is often filled unevenly. Therefore, in order to quantify radioactivity by gamma ray measurement,
In front of a gamma ray detector having a gamma ray collimator at the entrance, the container is moved in the axial direction and rotated around the axis of the container so that gamma rays emitted from inside the container are detected on an average basis,
The aim is to reduce quantitative errors due to non-uniform filling conditions.
放射性核種の定量精度は、その核種が放出する
ガンマ線の計数の統計精度にも依存するので、ガ
ンマ線パルス計数値は多い程良い。一方、測定時
間は短い程能率が大きいので、計数率を大きくし
て測定することが望ましい。 The accuracy of quantifying a radionuclide also depends on the statistical accuracy of counting gamma rays emitted by the nuclide, so the higher the gamma ray pulse count, the better. On the other hand, since the shorter the measurement time, the higher the efficiency, it is desirable to perform the measurement with a higher counting rate.
ところが、パルス型放射線測定回路系には、１
箇のガンマ線パルス検出毎に一定の不感時間があ
り、特に現在一般に使用されているガンマ線スペ
クトル測定用のMCAは、１パルスのエネルギ分
解記録に10〜40μ秒程度を要するため、放射能濃
度の高い部位を測定している時、104cps（カウン
ト／秒）程度以上の高計数率になると、不感時間
の割合がかなりの大きさとなる。 However, the pulsed radiation measurement circuit system has 1
There is a certain dead time for each gamma ray pulse detected, and in particular, the currently commonly used MCA for measuring gamma ray spectra requires about 10 to 40 μs to record the energy resolution of one pulse, so it is difficult to detect high radioactivity concentrations. When measuring a body part, if the counting rate is as high as about 10 4 cps (counts/second) or higher, the proportion of dead time becomes quite large.
従来、放射性廃棄物を充填した容器の回転スキ
ヤンは、一定速度で行つている。そのため、高濃
度放射能の部位の測定時の不感時間の比率増大が
測定値に影響をおよぼし、その部位の放射能量を
放射能濃度の低い部位に比し、相対的に過小評価
してしまうので、定量精度が低くなつてしまつて
いた。 Conventionally, a rotational scan of a container filled with radioactive waste is performed at a constant speed. Therefore, an increase in the proportion of dead time when measuring areas with high radioactivity concentrations will affect the measured values, leading to a relative underestimation of the amount of radioactivity in those areas compared to areas with low radioactivity concentrations. , the quantitative accuracy had become low.
本発明は上記の事情に基きなされたもので、不
感時間の割合の増加による定量精度低下を生じる
ことのない放射能定量法および装置を得ることを
目的とする。 The present invention was made based on the above-mentioned circumstances, and an object of the present invention is to provide a method and apparatus for quantifying radioactivity that does not cause a decrease in quantitative accuracy due to an increase in the proportion of dead time.
本発明においては、放射線検出器の前で被測定
試料を移動させて試料全体の放射能を定量するに
際して、放射線測定回路系の不感時間Ｎに応じ
て、１−Ｎに比例する速度で試料を移動すること
により、前記目的を達成している。 In the present invention, when moving a sample to be measured in front of a radiation detector to quantify the radioactivity of the entire sample, the sample is moved at a speed proportional to 1-N according to the dead time N of the radiation measurement circuit system. By moving, the above objective is achieved.
すなわち、前記の如くすることにより、試料中
の放射能の不均一に起因する不感時間割合の変動
により生じる定量精度の低下を防止することがで
きる。 That is, by doing as described above, it is possible to prevent a decrease in quantitative accuracy caused by fluctuations in the dead time ratio due to non-uniformity of radioactivity in the sample.
以下、実施例につき本発明の詳細を説明する。
第１図は本発明の一実施例のブロツク線図であ
る。被測定試料を充填した容器１はその軸を中心
としてパルスモータ２により回転および軸方向移
動されるようにしてある。また、容器１の側面に
はガンマ線コリメータを入射口にそなえたパルス
型ガンマ線検出器３が対向され、その出力は前置
増巾器４に入力されている。前置増巾器４には高
圧電源５により高圧が印加され、また制御パルス
発生器６により詳細を後に説明するパルス高の一
定周波数のパルスが印加されている。前置増巾器
４の出力は主増巾器７を介してMCA８に入力さ
れ、MCAの制御パルス波高に対応するチヤンネ
ルの出力は、パルス変換器９においてモータ駆動
用の電力パルスに１：１変換してパルスモータ２
に印加される。 Hereinafter, details of the present invention will be explained with reference to examples.
FIG. 1 is a block diagram of one embodiment of the present invention. A container 1 filled with a sample to be measured is rotated and moved in the axial direction by a pulse motor 2 about its axis. Further, a pulse type gamma ray detector 3 having a gamma ray collimator at its entrance is opposed to the side surface of the container 1, and its output is input to a preamplifier 4. A high voltage is applied to the preamplifier 4 by a high voltage power supply 5, and a pulse of a constant frequency and a pulse height whose details will be explained later is applied by a control pulse generator 6. The output of the preamplifier 4 is input to the MCA 8 via the main amplifier 7, and the output of the channel corresponding to the control pulse height of the MCA is converted into a power pulse for driving the motor at a 1:1 ratio in the pulse converter 9. Convert to pulse motor 2
is applied to
上記の構成において、制御パルスの波高を第２
図に示すように、MCAスペクトル例曲線Ａによ
り明らかなガンマ線計数のほとんどない高エネル
ギ側に入るように定める。第２図中、P1〜P3は
ガンマ線ピーク、Pcは制御パルス、ａは制御パ
ルスのMCAにおけるチヤンネルを示す。 In the above configuration, the wave height of the control pulse is set to the second
As shown in the figure, the MCA spectrum example curve A is set to fall on the high energy side where there are almost no obvious gamma ray counts. In FIG. 2, P 1 to P 3 indicate gamma ray peaks, Pc indicates a control pulse, and a indicates a channel of the control pulse in the MCA.
パルス変換器９には、制御パルスPcの波高値
に相当するチヤンネルにパルスが１つ入る毎にパ
ルスが送られ、容器駆動用のパルスモータ２に電
力パルスが１つ送られる。 A pulse is sent to the pulse converter 9 every time one pulse enters the channel corresponding to the peak value of the control pulse Pc, and one power pulse is sent to the pulse motor 2 for driving the container.
これにより、第３図に示す不感時間割合（％）
と回転速度Voとの関係が実施され、不感時間の
変動に基く定量精度の低下を防止することができ
る。 As a result, the dead time ratio (%) shown in Figure 3
The relationship between the rotational speed Vo and the rotational speed Vo can be established, and it is possible to prevent the quantitative accuracy from decreasing due to fluctuations in the dead time.
なお、本発明は上記実施のみに限定されない。
例えば、現在市販されているMCAには、不感時
間割合（％）を表示する機能を有するものがある
ので、これを利用して測定装置を構成するように
してもよい。すなわち、容器の回転をD.Cサーボ
モータ駆動とし、前記表示機能の信号を電圧信号
として取出し、サーボモータ速度制御器の制御入
力信号とする。このようにしても、容器の回転移
動速度は（１−Ｎ）に比例するものとすることが
でき、本発明の定量法を実施することができる。 Note that the present invention is not limited to the above implementation.
For example, some MCAs currently on the market have a function of displaying the dead time percentage (%), so this may be used to configure the measuring device. That is, the rotation of the container is driven by a DC servo motor, and the signal of the display function is taken out as a voltage signal and used as a control input signal of the servo motor speed controller. Even in this case, the rotational movement speed of the container can be made proportional to (1-N), and the quantitative method of the present invention can be carried out.
第１図は本発明一実施例のブロツク線図、第２
図、第３図は本発明の原理を説明するためのグラ
フである。
１……容器、２……パルスモータ、３……ガン
マ線検出器、４……前置増巾器、５……高圧電
源、６……制御パルス発生器、７……主増巾器、
８……MCA、９……パルス変換器。
Figure 1 is a block diagram of one embodiment of the present invention, Figure 2 is a block diagram of one embodiment of the present invention;
3 are graphs for explaining the principle of the present invention. 1... Container, 2... Pulse motor, 3... Gamma ray detector, 4... Preamplifier, 5... High voltage power supply, 6... Control pulse generator, 7... Main amplifier,
8...MCA, 9...Pulse converter.
Claims (1)
で測定し乍ら試料を移動させて試料全体の放射能
を定量するに際して、放射線測定回路系の不感時
間Ｎに応じて、試料の移動速度を（１−Ｎ）に比
例する速度とすることを特徴とする放射能定量
法。 ２ 被測定試料容器を駆動するパルスモータと、 容器側壁に対向したパルス型放射線検出器と、 この放射線検出器の出力を入力され放射線計数
のほとんどない領域の波高値の一定周波数制御パ
ルスを印加された前置増巾器と、 主増巾器を介して前記前置増巾器の出力を印加
された多重波高分析器と、 この多重波高分析器の前期制御パルスの波高に
相当するチヤンネルの出力をパルスモータ駆動用
電力パルスに１：１変換し前期パルスモータに印
加するパルス変換器 とを有することを特徴とする放射能定量装置。 ３ 被測定試料容器を駆動するD.Cサーボモータ
と、 前期容器側面に対向したパルス型放射線検出器
と、 前置増巾器，主増巾器を介して前記放射線検出
器の出力を印加され不感時間表示機能を有する多
重波高分析器と、 この多重波高分析器の前記表示機能の表示信号
を制御入力として前期D.Cサーボモータを制御す
る速度制御器 とを有することを特徴とする放射能定量装置。[Claims] 1. When measuring a portion of a sample to be measured with a pulse-type radiation detector and moving the sample to quantify the radioactivity of the entire sample, depending on the dead time N of the radiation measurement circuit system, A method for quantifying radioactivity, characterized in that the moving speed of the sample is proportional to (1-N). 2 A pulse motor that drives the sample container to be measured, a pulse type radiation detector facing the side wall of the container, and a constant frequency control pulse with a peak value in a region where there is almost no radiation count is applied to the output of this radiation detector. a multi-wavelength analyzer to which the output of the preamplifier is applied via the main amplifier; and an output of a channel corresponding to the wave height of the first control pulse of the multiple-wavelength analyzer. 1. A radioactivity quantification device comprising: a pulse converter that converts 1:1 into a pulse motor drive power pulse and applies the same to the pulse motor. 3 A DC servo motor that drives the sample container to be measured, a pulse-type radiation detector that faces the side of the container, and the output of the radiation detector is applied via the preamplifier and the main amplifier, resulting in a dead time. A radioactivity quantitative device comprising: a multiple wave height analyzer having a display function; and a speed controller that controls a DC servo motor using a display signal of the display function of the multiple wave height analyzer as a control input.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19710681A JPS5897678A (en) | 1981-12-08 | 1981-12-08 | Method and device for determination of radioactivity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19710681A JPS5897678A (en) | 1981-12-08 | 1981-12-08 | Method and device for determination of radioactivity |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5897678A JPS5897678A (en) | 1983-06-10 |
| JPH0350228B2 true JPH0350228B2 (en) | 1991-08-01 |
Family
ID=16368824
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19710681A Granted JPS5897678A (en) | 1981-12-08 | 1981-12-08 | Method and device for determination of radioactivity |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5897678A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0690288B2 (en) * | 1990-09-20 | 1994-11-14 | 株式会社日立製作所 | Radioactive waste inspection method and device |
| JP4869192B2 (en) * | 2007-09-18 | 2012-02-08 | 日立Ｇｅニュークリア・エナジー株式会社 | Radioactivity measurement method for radioactive waste |
-
1981
- 1981-12-08 JP JP19710681A patent/JPS5897678A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5897678A (en) | 1983-06-10 |
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