Development of a personal dosimeter applied for the photon and fast-neutron fields in high-energy accelerator facilities

高能加速器光子场和快中子场个人剂量计的研制

• 批准号: 16560048
• 负责人: TAWARA Hiroko
• 金额: $ 1.86万
• 依托单位: High Energy Accelerator Research Organization
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16560048/
• 关键词: Solid state nuclear track detector; CR-39; TLD; high energy neutrons; Personal dosimeter; Neutron dosimetry; Etch pit analysis; LET sistribution; 速中性子; 線量当量; 自動解析装置

1. As a first step toward developing a personal dosimeter applicable for fast neutrons (energy > 10 MeV), we tested the feasibility of using two-layer CR-39 stacks (0.9 mm in thickness x 2) to make LET distribution measurements for secondary charged particles due to fast neutrons of 0.25, 0.55, 5 and 15 MeV. The front layers of the detectors act as a radiator and the back layers act as a neutron detector. The results indicated the following: chemical etching shorter than 5 um is needed to obtain the correct LET distribution and dose for sub MeV neutrons; the present CR-39 detector system and chemical etching condition (bulk etch ~15 μm) are appropriate for 5 MeV neutron dosimetry, and measured dose equivalents and averaged quality factors for LET > 10 keV/μm agreed with the ICRP 74 neutron-fluence-to-dose conversion factor and the ICRP 60 radiation weighting factor, respectively; a thick radiator of ~2 mm is required for 15 MeV neutron dosimetry. Although the present measurements partl … More y failed to obtain correct LET values for the low-energy and short-range charged particles induced by fast neutrons, we conclude that modifications of the CR-39 detector system and chemical etching condition should improve the accuracy of LET distribution measurement for fast neutron dosimetry in the sub MeV to tens MeV energy range.2. An automated scanning system was developed for measuring a large number of nuclear track-etch detectors. We investigated scanning performance using CR-39 plastic samples irradiated by high-energy heavy ions and fast neutrons. Overall scanning speed including sample transfer, sample ID recognition, image acquisition and image analysis was satisfactorily high. The system allowed the processing of 100 samples with scan areas of 4 cm2/sample in one day for neutron dosimetry.3. A new software "LETDose" was developed for personal dosimetry. The software combines absorbed doses measured by TLDs and the LET distributions measured by CR-39 track detectors for estimating absorbed doses and dose equivalents for radiation fields consisting of photons and fast neutrons. Less

1. 作为开发适用于快中子（能量 > 10 MeV）的个人剂量计的第一步，我们测试了使用两层 CR-39 堆栈（厚度 0.9 mm x 2）对 0.25、0.55、5 和 15 MeV 快中子产生的二次带电粒子进行 LET 分布测量的可行性。探测器的前层充当辐射器，后层充当中子探测器。结果表明：需要小于 5 um 的化学蚀刻才能获得亚 MeV 中子的正确 LET 分布和剂量；目前的 CR-39 探测器系统和化学蚀刻条件（整体蚀刻 ~15 μm）适合 5 MeV 中子剂量测定，并且 LET > 10 keV/μm 的测量剂量当量和平均品质因数分别与 ICRP 74 中子注量-剂量转换因子和 ICRP 60 辐射权重因子一致； 15 MeV 中子剂量测定需要约 2 mm 厚的散热器。虽然目前的测量未能获得快中子引起的低能短程带电粒子的正确LET值，但我们得出的结论是，对CR-39探测器系统和化学刻蚀条件的修改应该可以提高亚MeV到数十MeV能量范围内快中子剂量测量的LET分布测量的精度。 2．开发了一种自动扫描系统，用于测量大量核径迹蚀刻探测器。我们使用高能重离子和快中子辐照的 CR-39 塑料样品研究了扫描性能。包括样本传输、样本 ID 识别、图像采集和图像分析在内的整体扫描速度令人满意。该系统一天内可处理100个样品，扫描面积为4 cm2/样品，用于中子剂量测定。3．开发了用于个人剂量测定的新软件“LETDose”。该软件结合了 TLD 测量的吸收剂量和 CR-39 径迹探测器测量的 LET 分布，用于估计由光子和快中子组成的辐射场的吸收剂量和剂量当量。较少的

项目成果

Development of an automated multisample scanning system for nuclear track etched detectors

开发用于核径迹蚀刻探测器的自动多样本扫描系统

• 发表时间: 2007
• 期刊: KEK-Preprint 2007-64
• 作者: Wijeyewickrema;A.C.;Hattori;M.;Leungvichchareon;S.;俵 裕子;Hiroko Tawara
• 通讯作者: Hiroko Tawara

Discovery of a strange tribaryon S^0(3115) in ^4He(K-stopped, p) reaction

^4He(K-stopped, p) 反应中发现奇怪的三重子 S^0(3115)

• 发表时间: 2004
• 期刊: Physics Letters B597
• 作者: Wijeyewickrema;A.C.;Hattori;M.;Leungvichchareon;S.;俵 裕子;Hiroko Tawara;Hiroko Tawara;T. Suzuki
• 通讯作者: T. Suzuki

Dosimetry for Neutrons from0.25to15MeV by the Measurement of LET Distributions for Secondary Charged Particles in CR-39 Plastic

通过测量 CR-39 塑料中二次带电粒子的 LET 分布来测定 0.25 至 15MeV 的中子剂量

• 发表时间: 2007
• 期刊: KEK-Preprint 2007-62
• 作者: Wijeyewickrema;A.C.;Hattori;M.;Leungvichchareon;S.;俵 裕子
• 通讯作者: 俵 裕子

Dosimetry for Neutrons from 0.25 to 15 MeV by the Measurement of LET Distributions for Secondary Charged Particles in CR-39 Plastic

通过测量 CR-39 塑料中二次带电粒子的 LET 分布来测定 0.25 至 15 MeV 的中子剂量

• 发表时间: 2007
• 期刊: KEK-Preprint 2007-62
• 作者: Wijeyewickrema;A.C.;Hattori;M.;Leungvichchareon;S.;俵 裕子;Hiroko Tawara;Hiroko Tawara
• 通讯作者: Hiroko Tawara

Feasibility study on deeply bound kaonic state

深度束缚高酸态的可行性研究

• 发表时间: 2001
• 期刊: Nuclear Instruments and Methods A473
• 作者: Wijeyewickrema;A.C.;Hattori;M.;Leungvichchareon;S.;俵 裕子;Hiroko Tawara;Hiroko Tawara;T. Suzuki;M. Iwasaki
• 通讯作者: M. Iwasaki