Study on improvement of sensitivity and spatial resolution in fast neutron imaging

快中子成像灵敏度和空间分辨率提高研究

• 批准号: 09480095
• 负责人: BABA Mamoru
• 金额: $ 3.65万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09480095/
• 关键词: Profile; Fast neutrons; Imaging plate; position sensitive counter; polyethylene converter; gamma-backgrounds; scattered neutrons; Contrast; 中性子イメージング; CH_2; 二次元カウンター; 像の歪み; 中性子イメージ; コンバータ; ポリエチレン; ラジオグラフィ; 位置敏感カウンタ; 二次元; 15MeV-10keV; ポリ

In the present study, we have investigated the method to improve the sensitivity and resolution in fast neutron profile measurement using 1) the combination of Imaging Plate (IP) and a polyethylene converter and 2) two-dimensional position sensitive counter, and achieved the following :1) By combining IP with a polyethylene converter with appropriate thickness, it became possible to measure fast neutron profile with good quality for 5-15 MeV mono-energetic neutrons produced by an accelerator within a few hours. It is also possible to measure a profile of neutrons with energy lower than a hundreds of keV using a ィイD16ィエD1LiF converter.2) We found the relation between the sensitivity vs energy deposit, converter thickness, spatial resolution, fading property, and the optimum irradiation condition for fast neutron profile measurements experimentally and theoretically. The optimum thickness of converters proved to be around the range of particles.3) We observed that the effect of scattered neutrons is serious for fast neutrons and separation of objects from IP is effective to reduce the effect, and that it is important to employ collimators made from nuclides which emit smaller number of gamma-rays.4) We designed and fabricated a two-dimensional position-sensitive counter using drift time and charge-division scheme to reduce the effects of gamma-ray backgrounds and scattered neutrons., and confirmed the possibility of the method.5) To enhance the portability and sensitivity of the counter, we slatted design of counters using a position -sensitive photo-multipliers.

在本研究中，我们研究了一种提高快中子剖面测量灵敏度和分辨率的方法：1)将成像板(IP)与聚乙烯转换器和2)二维位置灵敏计数器相结合，实现了以下结果：1)将IP与合适厚度的聚乙烯转换器相结合，可以在几小时内对加速器产生的5-15 MeV单能中子进行高质量的快中子剖面测量。用ィイD16ィエD1LiF换能器也可以测量能量低于几百keV的中子分布。2)我们从实验和理论上找到了灵敏度与能量沉积、换能器厚度、空间分辨率、衰减性以及测量快中子分布的最佳辐照条件的关系。3)我们观察到，对于快中子，散射中子的影响是严重的，物体与激电的分离是减少这种影响的有效方法，并且使用由发射较少伽马射线的核素制成的准直器是很重要的。4)为了减少伽马射线背景和散射中子的影响，我们设计并制作了一种二维位置灵敏计数器。

项目成果

T. Sanami, M. Baba et al.: "Fast neutron profiling using an Imaging Plate"Proc.11-th Workshop on Radiation Detector and Their Uses(1998, KEK). 403-408

T. Sanami、M. Baba 等人：“使用成像板进行快速中子分析”Proc.11-th Workshop on Radiation Detector and Their Uses（1998，KEK）。

M. Baba, T. Sanami et al.: "Measurement of neutron induced charged particle production cross sections for 5-90 MeV neutrons"Proc.10ィイD1thィエD1 Int.Workshop on Reactor Dosimetry (1999, Osaka). (to be published). (2000)

M. Baba、T. Sanami 等人：“5-90 MeV 中子的中子诱导带电粒子产生截面的测量”Proc.10 Int.Workshop on Reactor Dosimetry（1999 年，大阪）。

T.Sanami,M.Baba 他: "Measurement of(n,x α)cross section using gaseous samples and gridded ionization chamber" Proc.Int.Conf.Nucl.Data for Sci.Technol.,(Trieste,1997). 1. 616-618 (1998)

T. Sanami、M. Baba 等人：“使用气体样品和网格电离室测量 (n,x α) 横截面”Proc.Int.Conf.Nucl.Data for Sci.Technol.（的里雅斯特，1997 年） 1.616-618（1998）

K.Saito,M.Baba,他: "Fast Neutron Profiling using an Imaging Plate" CYRIC Annual Report 1997. 138-143 (1998)

K. Saito、M. Baba 等人：“使用成像板进行快速中子分析”CYRIC 年度报告 1997. 138-143 (1998)

T.MIura,M.Baba他: "Development of fast neutron profile methods"KEK Proceedings. (発行予定). (2000)

T. MIura、M. Baba 等人：“快中子剖面方法的发展”KEK 论文集（即将出版）。