JPH0634762A - Semiconductor type beta-ray measuring device - Google Patents
Semiconductor type beta-ray measuring deviceInfo
- Publication number
- JPH0634762A JPH0634762A JP18654592A JP18654592A JPH0634762A JP H0634762 A JPH0634762 A JP H0634762A JP 18654592 A JP18654592 A JP 18654592A JP 18654592 A JP18654592 A JP 18654592A JP H0634762 A JPH0634762 A JP H0634762A
- Authority
- JP
- Japan
- Prior art keywords
- beta
- ray
- semiconductor
- rays
- measuring device
- 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.)
- Pending
Links
Landscapes
- Measurement Of Radiation (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明はシリコン等の半導体素子
を用いた低エネルギβ線放出核種の測定装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring low energy β-ray emitting nuclides using a semiconductor element such as silicon.
【0002】[0002]
【従来の技術】従来の低エネルギβ線放出核種「トリチ
ウム(3H),カーボン(14C)等」の測定は凝縮や同位
体交換を伴った濃縮分離処理をした後、液体シンチレー
タでβ線放出核種を測定するのが一般的であった。この
方法では凝縮や同位体交換の濃縮分離処理が複雑になる
こと、液体シンチレータの測定装置が高価であること、
さらに、高度な濃縮分離技術と測定技術が要求されるこ
とにより適用範囲が限定されていた。2. Description of the Related Art Conventional low-energy β-ray emitting nuclides such as "tritium ( 3 H) and carbon ( 14 C)" are measured by a liquid scintillator after β-ray emission after concentration and separation treatment accompanied by condensation and isotope exchange. It was common to measure the emitted nuclide. This method complicates the concentration and separation process of condensation and isotope exchange, that the measuring device of the liquid scintillator is expensive,
Further, the application range was limited due to the requirement of advanced concentration and separation technology and measurement technology.
【0003】[0003]
【発明が解決しようとする課題】本発明の目的は、従来
要求されていた高度な濃縮分離技術と測定技術を不要に
し、かつ、低コストの低エネルギβ線放出核種測定装置
を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a low-energy low-energy β-ray emission nuclide measuring device that does not require the high-level concentration and separation techniques and measuring techniques that have been conventionally required. is there.
【0004】[0004]
【課題を解決するための手段】本発明の目的は、測定対
象のβ線放出ガスを選択的に透過させる膜分離処理を行
った後、低エネルギβ線を選択的に測定する半導体放射
線検出器で測定することによって達成できる。SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor radiation detector for selectively measuring low energy β-rays after performing a membrane separation process for selectively transmitting a β-ray emission gas to be measured. It can be achieved by measuring at.
【0005】[0005]
【作用】低エネルギβ線放出核種(3H,14C等)の測定
では、測定の妨害核種の影響を如何にして取り除くかと
いうことが重要なポイントとなる。本発明では、ガスの
膜分離技術で3H ,14C等を単純分離し、β線の測定で
は測定対象の低エネルギβ線にだけ有感となる二つの半
導体検出素子を対面するセル構造でβ線を選択的に測定
する。さらに、β線の測定では他のバックグランド放射
線(γ線,宇宙線等)を排除するため二つの半導体検出
素子の逆同時計数処理を付加する。この構成によって、
高度な濃縮分離や測定技術を不要にし、かつ、低コスト
の低エネルギβ線放出核種測定装置を提供できる。In the measurement of low energy β-ray emitting nuclides ( 3 H, 14 C, etc.), how to remove the influence of the interfering nuclides of the measurement is an important point. In the present invention, a gas membrane separation technique is used to simply separate 3 H, 14 C, etc., and a β-ray measurement has a cell structure in which two semiconductor detection elements facing each other are sensitive only to low-energy β-rays to be measured. Selectively measure β-rays. Further, in the measurement of β rays, an inverse coincidence counting process of two semiconductor detection elements is added to exclude other background radiation (γ rays, cosmic rays, etc.). With this configuration,
It is possible to provide a low-cost low-energy β-ray emission nuclide measuring device that does not require advanced concentration and separation or measurement technology.
【0006】[0006]
【実施例】以下、本発明の詳細な説明を実施例を用いて
説明する。図1は、本発明の半導体式低エネルギβ線測
定器の一実施例を示す。この測定器は測定流体の出入口
1とハウジング2から成る測定セルの内面に半導体検出
素子3,4を設ける。検出素子の電極取り出し構造は図
示せず(詳細後述)。半導体検出素子3,4はβ線の有
感面を対面する構造に設ける。図2に空気中のβ線飛程
を示す。3H のβ線エネルギは18.6keV で、その
飛程は約5mmであることが分かる。従って、3H を測定
対象とする場合、図1の半導体検出素子3,4の面間距
離(図1中5)は5から10mm(飛程の1倍から2
倍)に設定する構造が最適ということになる。すなわ
ち、放射性核種から放出するβ線は等方的であるので半
導体検出素子3,4の面間距離がこの寸法より大きくな
ると測定容積に対する感度が大幅に低下することにな
る。EXAMPLES The detailed description of the present invention will be given below with reference to examples. FIG. 1 shows an embodiment of the semiconductor low energy β-ray measuring device of the present invention. In this measuring device, semiconductor detecting elements 3 and 4 are provided on the inner surface of a measuring cell composed of a measuring fluid inlet / outlet 1 and a housing 2. The electrode extraction structure of the detection element is not shown (details will be described later). The semiconductor detection elements 3 and 4 are provided in a structure facing the sensitive surface of β rays. Fig. 2 shows the range of β rays in the air. It can be seen that the β-ray energy of 3 H is 18.6 keV and its range is about 5 mm. Therefore, when measuring 3 H, the surface distance (5 in FIG. 1) of the semiconductor detection elements 3 and 4 in FIG. 1 is 5 to 10 mm (1 to 2 times the range).
It means that the structure set to (double) is optimal. That is, since the β-rays emitted from the radionuclide are isotropic, if the interplanar distance between the semiconductor detection elements 3 and 4 is larger than this dimension, the sensitivity to the measurement volume will be significantly reduced.
【0007】図3に半導体検出素子構造を示す。ハウジ
ング2の内面に設けた半導体検出素子3のp−n接合6
に電極7と引出し電極7′を介して逆バイアスを印加す
る。引出し電極7′とハウジング2は絶縁材8で絶縁す
る。この逆バイアス印加状態ではp−n接合6に隣接し
て空乏層9が広がる。β線の検出原理はβ線が空乏層9
に入射することによって生成する電荷(電子−正孔対)
を利用する。シリコン中の3H のβ線飛程は約2.5μ
m であり、空乏層9の厚さをこの値に設定できれば3H
のβ線を選択的に測定できることになる。β線検出の
不感層となるp−n接合6と電極7の厚さは0.2μm
以下に製作可能であり、無視できる。空乏層の厚さtは
印加バイアスの電圧Vに依存し、次の関係で決まる。FIG. 3 shows a semiconductor detection element structure. The pn junction 6 of the semiconductor detection element 3 provided on the inner surface of the housing 2
A reverse bias is applied to the electrode 7 via the electrode 7 and the extraction electrode 7 '. The extraction electrode 7 ′ and the housing 2 are insulated by the insulating material 8. In this reverse bias applied state, the depletion layer 9 spreads adjacent to the pn junction 6. The principle of β-ray detection is that β-ray is depleted layer 9
Charge (electron-hole pair) generated by incident on
To use. Β range of 3 H in silicon is about 2.5μ
m, and if the thickness of the depletion layer 9 can be set to this value, 3 H
Therefore, the β ray of can be selectively measured. The thickness of the pn junction 6 and the electrode 7, which are insensitive layers for β-ray detection, is 0.2 μm.
The following can be produced and can be ignored. The thickness t of the depletion layer depends on the applied bias voltage V and is determined by the following relationship.
【0008】[0008]
【数1】 [Equation 1]
【0009】ρ:半導体の抵抗率(Ω・cm) C:定数 n型半導体を用いる場合、抵抗率50Ω・cm、逆バイア
ス1Vの印加で数μmの空乏層を作ることができる。妨
害となるバックグランド放射線(γ線、宇宙線等)は透
過力が大きく、この薄い空乏層で妨害放射線の影響を低
く抑えることができる。Ρ: Resistivity of semiconductor (Ω · cm) C: Constant When an n-type semiconductor is used, a depletion layer of several μm can be formed by applying a resistance of 50 Ω · cm and a reverse bias of 1V. Background radiation (γ-rays, cosmic rays, etc.) that becomes an obstacle has a large penetrating power, and the influence of the disturbing radiation can be suppressed to a low level by this thin depletion layer.
【0010】図4に本発明の計測回路ブロック図を示
す。ハウジング2の内面に対面して設けた半導体検出素
子3,4から引出し電極7′を介してβ線の検出信号を
取り出す。V1,V2は逆バイアス印加部を示す。それぞ
れの出力信号はカップリングコンデンサ10,10′を
介して、前置増幅器11,11′,線形増幅器12,1
2′を接続する。その後段に両出力信号の逆同時計数回
路13,放射能演算器14,表示器15を設ける。透過
力の大きいバックグランド放射線は半導体検出素子3,
4の両者を透過するため、出力信号も両検出素子から同
時に出力される確率が高い。単独に出力があった場合に
だけβ選出力とする逆同時計数処理はバックグランド放
射線を大幅に排除する。この処理によって、妨害放射線
の影響をさらに低減することができる。FIG. 4 shows a block diagram of the measuring circuit of the present invention. A β-ray detection signal is taken out from the semiconductor detection elements 3 and 4 provided facing the inner surface of the housing 2 through the extraction electrode 7 '. V 1 and V 2 represent reverse bias applying sections. The respective output signals are passed through the coupling capacitors 10 and 10 'to the preamplifiers 11 and 11' and the linear amplifiers 12 and 1, respectively.
Connect 2 '. An inverse coincidence counting circuit 13, a radioactivity calculator 14, and a display 15 for both output signals are provided at the subsequent stage. The background radiation having a large penetrating power is detected by the semiconductor detection element 3,
Since it passes through both No. 4 and No. 4, there is a high probability that the output signals are simultaneously output from both detection elements. Inverse coincidence counting processing, in which β selection output is performed only when there is a single output, largely eliminates background radiation. By this processing, the influence of disturbing radiation can be further reduced.
【0011】図5に本発明の装置構成を示す。放射性流
体の流入部に測定対象物だけを透過する分離膜21(測
定対象外の物質の排出配管は図示せず)を設け、その後
段に半導体式β線測定器20A,20B,………,20
nを直列配置で設ける。この構成によって、n倍の感度
向上が図れる。分離膜21には、3H 用としてパラジウ
ム合金膜、14C(炭酸ガス)用としてポリイミド膜(高
分子膜)などが適用できる。FIG. 5 shows a device configuration of the present invention. A separation membrane 21 (a discharge pipe for a substance other than the measurement target is not shown) that allows only the measurement target to permeate is provided in the inflow part of the radioactive fluid, and the semiconductor β-ray measuring instruments 20A, 20B, ... 20
n are arranged in series. With this configuration, sensitivity can be improved n times. As the separation film 21, a palladium alloy film for 3 H, a polyimide film (polymer film) for 14 C (carbon dioxide), and the like can be applied.
【0012】図6には本発明の変形例で、β線測定器2
0A,20B,………,20nを並列配置する高感度化
の構成を示す。この構成によっても同様の高感度化を容
易に達成できる。FIG. 6 shows a modification of the present invention, which is a β-ray measuring device 2
0A, 20B, ..., 20n are arranged in parallel to increase the sensitivity. With this configuration, the same high sensitivity can be easily achieved.
【0013】以上で説明した測定対象流体はガス状、液
体状のいずれにも同一思想で設計できるものである。ま
た、以上の説明はシリコン半導体を例に取っているが、
当然テルル化カドミウム等の他半導体検出素子に置き換
えることも容易に可能である。The fluid to be measured described above can be designed in the same idea in both gas and liquid. In addition, although the above description uses a silicon semiconductor as an example,
Of course, other semiconductor detection elements such as cadmium telluride can be easily replaced.
【0014】本実施例を用いることによって、装置構成
が単純で高感度、低コストの低エネルギβ線放出核種測
定装置を提供することができる。By using this embodiment, it is possible to provide a low energy β-ray emitting nuclide measuring device having a simple structure, high sensitivity and low cost.
【0015】[0015]
【発明の効果】本発明によれば、高度な濃縮分離技術と
測定技術を不要にし、かつ、低コストで実用的なβ線放
出核種測定装置を提供することができる。Industrial Applicability According to the present invention, it is possible to provide a practical β-ray emission nuclide measuring device which does not require a high-level concentration and separation technique and a measuring technique and is low in cost.
【図1】本発明の半導体式低エネルギβ線測定器の一実
施例を示す説明図。FIG. 1 is an explanatory view showing an embodiment of a semiconductor type low energy β ray measuring device of the present invention.
【図2】空気中のβ線飛程を示す特性図。FIG. 2 is a characteristic diagram showing a β-ray range in air.
【図3】半導体検出素子構造を示す説明図。FIG. 3 is an explanatory diagram showing a semiconductor detection element structure.
【図4】本発明の計測回路のブロック図。FIG. 4 is a block diagram of a measuring circuit of the present invention.
【図5】本発明の装置構成を示す説明図。FIG. 5 is an explanatory diagram showing a device configuration of the present invention.
【図6】本発明の変形例を示す説明図。FIG. 6 is an explanatory diagram showing a modified example of the present invention.
2…ハウジング、3,4…半導体検出素子、7′…電
極、10,10′…カップリングコンデンサ、11,1
1′…前置増幅器、12,12′…線形増幅器、13…
逆同時計数回路、14…放射能演算器、15…表示器。2 ... Housing, 3, 4 ... Semiconductor detection element, 7 '... Electrode, 10, 10' ... Coupling capacitor, 11, 1
1 '... Preamplifier, 12, 12' ... Linear amplifier, 13 ...
Inverse coincidence counting circuit, 14 ... Radioactivity calculator, 15 ... Display.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 佐藤 克利 茨城県日立市森山町1168番地 株式会社日 立製作所エネルギー研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsutoshi Sato 1168 Moriyama-cho, Hitachi-shi, Ibaraki Pref.
Claims (4)
たセル構造のβ線測定器と、その対面する検出素子の出
力信号を逆同時計測する回路からなることを特徴とする
半導体式β線測定装置。1. A semiconductor device characterized by comprising a β-ray measuring device having a cell structure in which the sensitive surfaces of a plurality of semiconductor detecting elements are faced to each other, and a circuit for simultaneously and inversely measuring output signals of the facing sensing elements. Beta-ray measuring device.
有感面を対面させたセル構造の面間距離を測定対象のβ
線飛程の2倍以内に設定してなるβ線測定器を用いた半
導体式β線測定装置。2. The interplanar distance of a cell structure, in which the sensitive surface of the semiconductor detection element faces, according to claim 1, wherein β is a measurement target.
A semiconductor β-ray measuring device that uses a β-ray measuring device that is set within twice the range of rays.
る分離膜を介してサンプルを流入させる機器を付加する
半導体式β線測定装置。3. The semiconductor type β ray measuring apparatus according to claim 1, wherein a device for introducing a sample through a separation membrane for separating the β ray emitting substance is added.
列、あるいは並列に配置してサンプルを同時に流入させ
る半導体式β線測定装置。4. The semiconductor β-ray measuring device according to claim 1, wherein a plurality of β-ray measuring devices are arranged in series or in parallel and a sample is simultaneously introduced.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18654592A JPH0634762A (en) | 1992-07-14 | 1992-07-14 | Semiconductor type beta-ray measuring device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18654592A JPH0634762A (en) | 1992-07-14 | 1992-07-14 | Semiconductor type beta-ray measuring device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0634762A true JPH0634762A (en) | 1994-02-10 |
Family
ID=16190384
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP18654592A Pending JPH0634762A (en) | 1992-07-14 | 1992-07-14 | Semiconductor type beta-ray measuring device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0634762A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9213370B2 (en) | 2011-10-07 | 2015-12-15 | Fujitsu Limited | Housing, double-sided adhesive tape, and electronic apparatus |
-
1992
- 1992-07-14 JP JP18654592A patent/JPH0634762A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9213370B2 (en) | 2011-10-07 | 2015-12-15 | Fujitsu Limited | Housing, double-sided adhesive tape, and electronic apparatus |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10132936B2 (en) | Alpha particle detection apparatus using dual probe structured ionization chamber and differential amplifier | |
Ahmad et al. | Nuclear spectroscopy with Si PIN diode detectors at room temperature | |
Morishita et al. | Radon measurements with a compact, organic-scintillator-based alpha/beta spectrometer | |
Gooda et al. | High resolution alpha spectroscopy with low cost photodiodes | |
Eriksson et al. | Plutonium hot particle separation techniques using real-time digital image systems | |
JPH0634762A (en) | Semiconductor type beta-ray measuring device | |
JP4136301B2 (en) | Radioactive ion detector | |
US20040200968A1 (en) | Apparatus and method for detecting alpha-ray | |
JPH065291B2 (en) | Radiation detector | |
JPH08136663A (en) | Radon/thoron measuring instrument | |
RU2759244C1 (en) | Compact space radiation detector for use on small spacecraft | |
SU788468A1 (en) | Method for radioisotopic investigation of microhemocirculation in skin | |
CN112051603B (en) | Device and method for detecting radon content | |
Aniansson | Thin CsI (TII) Scintillating Layers Produced by Vacuum Deposition | |
KR200364507Y1 (en) | Advanced Radon Monitor using Two Chambers with P·N Junction Detector | |
JPH10186036A (en) | Radon concentration measuring method and its device | |
JPS63285485A (en) | Detecting apparatus of radiation contamination density | |
Abdalla et al. | Radon calibration system | |
Muraki et al. | The properties of Norikura solar neutron telescope# 2 | |
Masevhe et al. | Meteorological effects on the performance of a solid-state α―detector measuring water samples with predefined radon concentration | |
Santos et al. | The measurement of the half-life of the second excited state of 237Np with a new detector system and digital electronics | |
Roux et al. | A Neutron Detection System for Operation in Very High Gamma Fields | |
Nielson et al. | Development of a plutonium-americium monitor for in situ soil surface and pond bottom assay | |
Alpat et al. | Multipurpose high sensitivity radiation detector: Terradex | |
SU849874A1 (en) | Device for measuring low specific activity of -radioactive preparations |