JP2000056098A - Low-energy neutron radiating device - Google Patents
Low-energy neutron radiating deviceInfo
- Publication number
- JP2000056098A JP2000056098A JP10224552A JP22455298A JP2000056098A JP 2000056098 A JP2000056098 A JP 2000056098A JP 10224552 A JP10224552 A JP 10224552A JP 22455298 A JP22455298 A JP 22455298A JP 2000056098 A JP2000056098 A JP 2000056098A
- Authority
- JP
- Japan
- Prior art keywords
- neutron
- energy
- low
- neutrons
- multiplication
- 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.)
- Withdrawn
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、各種検査に用いら
れる中性子非破壊検査装置の中性子照射装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a neutron irradiation device used for various inspections.
【０００２】[0002]
【従来の技術】中性子非破壊検査装置は、元素分析、爆
発物検査、石油探査、水分計、航空機機体検査、火工品
検査、管内流体検査等に用いられているが、検査対象に
照射される中性子としては、エネルギーの低いものが使
用されている。１MeV程度までの中速中性子では、原子
炉等の経験から軽水（Ｈ２Ｏ）、重水（Ｄ２Ｏ）、グラ
ファイト、パラフィンなどの軽元素から構成される減速
材中で弾性散乱反応を用いてeVレベルの低エネルギー中
性子へ減速する方法が有効であることが知られている。
そのため、数ＭeVの高エネルギー中性子の減速にも同様
の方法が採られていた。2. Description of the Related Art Neutron non-destructive inspection devices are used for elemental analysis, explosives inspection, petroleum exploration, moisture meter, aircraft body inspection, pyrotechnics inspection, pipe fluid inspection, etc. Low energy neutrons are used. For medium-speed neutrons up to about 1 MeV, based on experience in nuclear reactors, etc., the elastic scattering reaction was used in a moderator composed of light elements such as light water (H 2 O), heavy water (D 2 O), graphite, and paraffin. It is known that a method of decelerating to low energy neutrons at eV level is effective.
For this reason, a similar method has been adopted for decelerating high-energy neutrons of several MeV.
【０００３】[0003]
【発明が解決しようとする課題】然るに、前述のような
減速過程では、競合過程として中性子が原子核に吸収さ
れる捕獲反応が存在し、低エネルギー中性子として照射
容器から得られる個数は、放射性同位元素或いは電子式
中性子発生装置から得られる中性子数に比べ、極めて小
さいものになっていた。このため、所要数の低エネルギ
ー中性子を得るためには、放射性同位元素或いは電子式
中性子発生装置の出力を上げねばならず、高いレベルの
放射能を取り扱わなければならないという問題があっ
た。従って、本発明の目的は、相対的に出力の小さい放
射性同位元素或いは電子式中性子発生装置を用いても、
必要な数の低エネルギー中性子が得られる、取扱が容易
で安全な低エネルギー中性子照射装置を提供するにあ
る。However, in the deceleration process as described above, there is a capture reaction in which neutrons are absorbed into the nucleus as a competitive process, and the number of low-energy neutrons obtained from the irradiation vessel is determined by the radioisotope. Alternatively, the number of neutrons is extremely smaller than the number of neutrons obtained from an electronic neutron generator. Therefore, in order to obtain a required number of low-energy neutrons, the output of a radioisotope or electronic neutron generator must be increased, and a high level of radioactivity must be handled. Therefore, the object of the present invention is to use a relatively small output radioisotope or electronic neutron generator,
An object of the present invention is to provide an easy-to-use and safe low-energy neutron irradiation apparatus that can obtain a required number of low-energy neutrons.
【０００４】[0004]
【課題を解決するための手段】如上の目的を達成するた
め、本発明によれば、中性子非破壊検査装置全般に用い
られる低エネルギー中性子照射装置は、放射性同位元素
又は電子式中性子発生装置等の高エネルギー中性子源
と、その高エネルギー中性子源を取り囲む中性子増倍減
速領域と、同中性子増倍減速領域を取り囲み照射方向の
みが開いた照射容器とから構成され、前記中性子増倍減
速領域は中性子増倍反応の反応断面積が大きい鉛又はベ
リリウム等の核種から形成されていることを特徴とす
る。According to the present invention, a low-energy neutron irradiator used in a neutron nondestructive inspection apparatus generally includes a radioisotope or an electronic neutron generator. A high-energy neutron source, a neutron multiplication-moderation region surrounding the high-energy neutron source, and an irradiation container surrounding the neutron multiplication-deceleration region and having only an irradiation direction open, and the neutron multiplication-deceleration region is a neutron multiplication-mode The doubling reaction is characterized by being formed from a nuclide such as lead or beryllium having a large reaction cross section.
【０００５】[0005]
【発明の実施の形態】以下添付の図面を参照して本発明
の実施形態を説明する。図１及び図２を参照するに、高
エネルギー中性子源である放射性同位元素１は、水素化
合物乃至コンクリートなどの中性子吸収物質からなる中
性子照射容器３の中に形成された中性子増倍減速領域即
ち鉛ブロック５の中に設置される。図から判るように、
中性子照射容器３は一面（図１において下側）のみが開
放している。Embodiments of the present invention will be described below with reference to the accompanying drawings. Referring to FIG. 1 and FIG. 2, a radioisotope 1 which is a high energy neutron source includes a neutron multiplication moderation region, that is, lead, formed in a neutron irradiation vessel 3 made of a neutron absorbing material such as a hydrogen compound or concrete. It is installed in block 5. As you can see from the figure,
Only one surface (the lower side in FIG. 1) of the neutron irradiation container 3 is open.
【０００６】以上のような構成の低エネルギー中性子照
射装置１０では、放射性同位元素１から出た数MeVの高
エネルギー中性子は、鉛ブロック５の中で中性子増倍反
応（（ｎ，２ｎ）反応）を起こし、中性子を増倍し、減
速する。図３に鉛Pb２０８の中性子吸収断面積が示され
ている。この図から判るように、鉛ブロック５は１個の
高エネルギー中性子を受けて２個の低エネルギー中性子
を出す。この低エネルギー中性子７は図示しない検査対
象物に向かって放出される。図４に本実施形態によって
得られる中性子エネルギースペクトルＩを従来のものの
中性子エネルギースペクトルIIと対比して示している。
従来のものは炭素減速材を用いたもので、中性子のエネ
ルギーレベルが数ＭeVにおいて、中性子強度が数倍にな
っていることが理解できよう。尚、図４の縦軸及び横軸
は対数目盛である。In the low-energy neutron irradiation apparatus 10 having the above configuration, high-energy neutrons of several MeV emitted from the radioisotope 1 are subjected to a neutron multiplication reaction ((n, 2n) reaction) in the lead block 5. Cause neutron multiplication and deceleration. FIG. 3 shows a neutron absorption cross section of lead Pb208. As can be seen from this figure, the lead block 5 receives one high energy neutron and emits two low energy neutrons. The low-energy neutrons 7 are emitted toward an inspection object (not shown). FIG. 4 shows a neutron energy spectrum I obtained by this embodiment in comparison with a conventional neutron energy spectrum II.
The conventional one uses a carbon moderator, and it can be understood that the neutron intensity is several times higher when the energy level of the neutron is several MeV. The vertical and horizontal axes in FIG. 4 are logarithmic scales.
【０００７】図５に中性子の増倍減速領域の構成物質と
して用いられるベリリウムの中性子吸収断面積が示され
ている。この図からも理解されるように、ベリリウムも
鉛と同様に数ＭeVの中性子に対し、吸収断面積が大き
く、鉛と同様の作用効果が得られることが理解されよ
う。又、高エネルギー中性子源として、電子式中性子発
生装置を用いる場合は、図６に示すように低エネルギー
中性子発生装置２０を構成する。即ち、照射容器１３を
貫いて電子式中性子発生装置１１の中性子導出部が延
び、鉛ブロック１５の中に、中性子放出部が位置する。
このようにすれば、前述の低エネルギー中性子発生装置
１０と同様な作用効果が得られることは明らかであろ
う。FIG. 5 shows a neutron absorption cross section of beryllium used as a constituent material of the neutron multiplication and deceleration region. As can be understood from this figure, beryllium has a large absorption cross-section for neutrons of several MeV like lead, and it can be understood that the same operation and effect as lead can be obtained. When an electronic neutron generator is used as the high energy neutron source, the low energy neutron generator 20 is configured as shown in FIG. That is, the neutron deriving section of the electronic neutron generator 11 extends through the irradiation container 13, and the neutron emitting section is located in the lead block 15.
By doing so, it is apparent that the same operation and effect as those of the low-energy neutron generator 10 described above can be obtained.
【０００８】[0008]
【発明の効果】以上説明したように、本発明によれば、
鉛やベリリウムで構成される増倍減速領域の中で、高エ
ネルギー中性子を放出し、中性子増倍反応（（n，２n）
反応）を利用して低エネルギー中性子を発生させ、照射
するので、中性子の数を減らすことが無く、高エネルギ
ー中性子源が小出力でも中性子の数を確保して所期の非
破壊検査を可能にすることができる。As described above, according to the present invention,
High energy neutrons are emitted in the multiplication moderation region composed of lead and beryllium, and neutron multiplication reaction ((n, 2n)
Reaction) to generate and irradiate low-energy neutrons, so that the number of neutrons is not reduced, and even if the high-energy neutron source has a small output, the number of neutrons is ensured, enabling the expected nondestructive inspection. can do.
【図１】本発明の実施形態を示す概念図である。FIG. 1 is a conceptual diagram showing an embodiment of the present invention.
【図２】図１のII−II線に沿う断面図である。FIG. 2 is a sectional view taken along the line II-II in FIG.
【図３】本発明による実施形態の作用を説明するための
グラフである。FIG. 3 is a graph for explaining the operation of the embodiment according to the present invention.
【図４】前記実施形態の作用を説明するためのグラフで
ある。FIG. 4 is a graph for explaining the operation of the embodiment.
【図５】本発明の中性子増倍減速領域を形成するベリリ
ウムの中性子吸収断面積を示すグラフである。FIG. 5 is a graph showing a neutron absorption cross section of beryllium that forms a neutron multiplication deceleration region of the present invention.
【図６】前記実施形態の一部を改変した改変実施形態の
概念図である。FIG. 6 is a conceptual diagram of a modified embodiment in which a part of the embodiment is modified.
【符号の説明】 １ 放射性同位元素 ３ 照射容器 ５ 鉛ブロック ７ 低エネルギー中性子 １０ 低エネルギー中性子照射装置 １１ 電子式中性子発生装置 １３ 照射容器 １５ 鉛ブロック ２０ 低エネルギー中性子照射装置[Description of Signs] 1 Radioactive isotope 3 Irradiation container 5 Lead block 7 Low energy neutron 10 Low energy neutron irradiation device 11 Electronic neutron generator 13 Irradiation container 15 Lead block 20 Low energy neutron irradiation device
Claims (2)
ー中性子源を取り囲む中性子増倍減速領域と、同中性子
増倍減速領域を取り囲み照射方向のみが開いた照射容器
とから構成され、前記中性子増倍減速領域は中性子増倍
反応の反応断面積が大きい核種から形成されていること
を特徴とする低エネルギー中性子照射装置。1. A neutron multiplier comprising: a high-energy neutron source; a neutron multiplication-moderation region surrounding the high-energy neutron source; and an irradiation container surrounding the neutron multiplication-moderation region and having only an irradiation direction open. A low-energy neutron irradiation apparatus characterized in that the deceleration region is formed from a nuclide having a large reaction cross section of the neutron multiplication reaction.
記高エネルギー中性子源が放射性同位元素又は電子式中
性子発生装置であることを特徴とする請求項１記載の低
エネルギー中性子照射装置。2. The low energy neutron irradiation apparatus according to claim 1, wherein said nuclide is lead or beryllium, and said high energy neutron source is a radioisotope or electronic neutron generator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10224552A JP2000056098A (en) | 1998-08-07 | 1998-08-07 | Low-energy neutron radiating device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10224552A JP2000056098A (en) | 1998-08-07 | 1998-08-07 | Low-energy neutron radiating device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000056098A true JP2000056098A (en) | 2000-02-25 |
Family
ID=16815581
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10224552A Withdrawn JP2000056098A (en) | 1998-08-07 | 1998-08-07 | Low-energy neutron radiating device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000056098A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006047115A (en) * | 2004-08-04 | 2006-02-16 | Mitsubishi Heavy Ind Ltd | Neutron generating apparatus, target and neutron irradiation system |
| KR101452790B1 (en) * | 2012-12-11 | 2014-10-22 | 한국수력원자력(주) | Californium neutron source container with optimum lead shielding |
-
1998
- 1998-08-07 JP JP10224552A patent/JP2000056098A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006047115A (en) * | 2004-08-04 | 2006-02-16 | Mitsubishi Heavy Ind Ltd | Neutron generating apparatus, target and neutron irradiation system |
| KR101452790B1 (en) * | 2012-12-11 | 2014-10-22 | 한국수력원자력(주) | Californium neutron source container with optimum lead shielding |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20051101 |