面向个人剂量计校准的小尺度伽玛参考辐射模拟研究

钱易坤; 冯鹏; 刘易鑫; 朱亚地; 黄宇晨; 张颂; 何鹏; 魏彪; 毛本将

doi:10.11884/HPLPB202133.200280

面向个人剂量计校准的小尺度伽玛参考辐射模拟研究

doi: 10.11884/HPLPB202133.200280

钱易坤^{1, 2,},
冯鹏²,
刘易鑫¹,
朱亚地¹,
黄宇晨^{1, 2},
张颂^{1, 2},
何鹏²,
魏彪²,
毛本将^1, ,

1.
中国工程物理研究院核物理与化学研究所，四川绵阳 621900
2.
重庆大学光电工程学院，重庆 400044

基金项目: 重庆大学中央高校基本科研业务费资助项目（2018CDGFGD0008）；国家自然科学基金青年基金项目（11805111）；国防科工局研究课题

详细信息

作者简介:
钱易坤（1992—），男，博士研究生，从事电离辐射计量研究；626578507@qq.com

通讯作者:
毛本将（1965—），男，研究员，从事电离辐射计量研究；gena@vip.sina.com

中图分类号: TL72
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出版历程
- 收稿日期: 2020-10-11
- 修回日期: 2021-01-19
- 网络出版日期: 2021-03-09
- 刊出日期: 2021-04-15

Personal dosimeter calibration based on minitype reference radiation

Qian Yikun^{1, 2
,},
Feng Peng²,
Liu Yixin¹,
Zhu Yadi¹,
Huang Yuchen^{1, 2},
Zhang Song^{1, 2},
He Peng²,
Wei Biao²,
Mao Benjiang^{1
, ,}

1.
China Academy of Engineering Physics, Mianyang 621900, China
2.
College of Optoelectronics Engineering, Chongqing University, Chongqing 400044, China

摘要

摘要: 针对伽玛射线个人剂量计基于标准伽玛参考辐射进行校准时检定效率低、校准工作复杂和需要远程送检的关键技术问题，建构了1 Ci ¹³⁷Cs放射源小尺度参考辐射场物理模型，采用蒙特卡罗方法，研究了小尺度参考辐射场内的剂量分布、装置结构和待检剂量计变化导致散射射线对剂量场的影响，获得了待检剂量计形状、数量、类型和装置结构产生的散射伽玛射线对小尺度参考辐射量值定度的影响结果。研究结果表明，1 Ci ¹³⁷Cs可以为小尺度参考辐射辐射场检验点提供1.5 mSv/h的伽玛遂行剂量率，辐照个人剂量计载台直径30 cm束斑上的剂量率相对标准偏差约为0.48%。当载台厚度为20 mm时，散射射线对小尺度参考辐射检验点处剂量率值的影响率为3.27%，高于剂量计尺寸（1.62%）和剂量计数量（0.56%）的影响。
- 个人剂量计 /
- 剂量量值定度 /
- 小尺度参考辐射 /
- 蒙特卡罗方法 /
- 遂行校准
Abstract: Gamma-ray personal dosimeters are important tools for the radiation protection for workers. However, the current calibration method based on standard reference radiation has low verification efficiency, large calibration workload, and requires remote inspection. To solve the above problems, this paper attempts to apply the minitype reference radiation to the calibration of gamma-ray personal dosimeters. The Monte Carlo method is used to simulate the dose distribution in the minitype reference radiation field, the influence of scattering rays which are caused by the device structure and dosimeters in the dose field. The results show that 1 Ci ¹³⁷Cs can provide a dose rate of 1.5 mSv/h for the point of test, and the relative standard deviation of the dose rate at the point of test is about 0.48%. When the thickness of the stage is 20 mm, the influence rate of scattered rays on the dose rate value at the minitype reference radiation inspection point is 3.27%, which is higher than the influence of the size of the dosimeter (1.62%) and the number of dosimeters (0.56%). This paper provides a theoretical basis for in situ calibration to calibrate gamma-ray personal dosimeters.
- personal dosimeter /
- dose value calibration /
- minitype reference radiation /
- Monte Carlo method /
- in situ calibration

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图 1 伽玛射线剂量校准MRR物理模型原理图

Figure 1. Physical models of MRR for gamma-ray dose calibration

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图 2 沿射线束照射方向检验点剂量率分布情况

Figure 2. Distribution of dose rate along the irradiation direction

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图 3 载台厚度变化对检验点处散射射线能量的影响

Figure 3. Gamma energy spectrum with different thickness of stage at the point of test

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图 4 剂量计尺寸变化对检验点处散射射线能量的影响

Figure 4. Gamma spectra at the point of test with the size change of dosimeters

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图 5 剂量计数量变化对检验点处散射射线能量的影响

Figure 5. Gamma spectra at the point of test with the number change of dosimeters

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图 6 不同情况下散射监测点处的散射能谱

Figure 6. Spectrum at scattering monitoring point

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图 7 不同因素变化对监测点的伽玛能谱的影响情况

Figure 7. Scattering spectrum at scattering monitoring point under different conditions

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表 1 载台厚度对检验点剂量率值影响一览表

Table 1. Impact rate of the stage thickness on the dose rate of the point of test

thickness of stage/mm	dose rate at the point of test/（mSv/h）	impact rate/%	error/%
5	1.383	1.14	0.11
10	1.395	2.00	0.11
15	1.404	2.70	0.11
20	1.412	3.27	0.11
25	1.419	3.78	0.11
30	1.424	4.20	0.11
35	1.430	4.57	0.09
40	1.434	4.90	0.09

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表 2 剂量计尺寸对检验点剂量率值影响一览表

Table 2. Impact rate of the dosimeter size on the dose rate of the point of test

size of dosimeter/(mm×mm×mm)	dose rate at the point of test/（mSv/h）	impact rate/%	error/%
10×3×8	1.427	1.62	0.03
8×3×8	1.419	1.08	0.04
8×3×6	1.411	0.46	0.04
8×3×4	1.397	−0.47	0.05
8×2×4	1.414	0.70	0.05
8×1×4	1.420	1.11	0.05

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表 3 剂量计数量对检验点剂量率值影响情况一览表

Table 3. Impact rate of the dosimeter number on the dose rate of the point of test

number of dosimeter/mm	dose rate at the point of test/（mSv/h）	impact rate/%	error/%
1	1.400	0.10	0.10
2	1.401	0.15	0.09
4	1.402	0.24	0.10
8	1.407	0.56	0.11

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表 4 不确定度因素分析

Table 4. Analysis of uncertainty factors

uncertainty factor	reference condition	error value/%	uncertainty component/%
MRR box	60 cm×60 cm×60 cm	0.08	0.05
thickness change of stage	20 mm	3.27	1.89
size change of dosimeters	10 mm×3 mm×8 mm	1.62	0.94
number change of dosimeters	8	0.56	0.32
combined standard uncertainty	—	—	3.20

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参考文献(14)

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