重复频率高功率微波加速器X射线屏蔽的估算

Yang Hanwu; Xun Tao; Gao Jingming; Zhang Zicheng

doi:10.11884/HPLPB201830.170532

重复频率高功率微波加速器X射线屏蔽的估算

doi: 10.11884/HPLPB201830.170532

国防科技大学前沿交叉学科学院, 长沙 410073

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中图分类号: TN146
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出版历程
- 收稿日期: 2017-12-30
- 修回日期: 2018-02-27
- 刊出日期: 2018-07-15

X-ray shielding estimations for rep-rate high power microwave accelerators

College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China

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Author Bio:
Yang Hanwu(1974-), male, research professor, engaged in pulsed power and high power microwave technologies; yanghw@nudt.edu.cn

摘要

摘要: 高功率微波的研究正在向高重复频率发展，目前已运行每年百万炮次或以上的水平，由此导致的电子束轫致辐射产生的X射线剂量已不可忽视，为了人员安全必须采取屏蔽措施。采用BEAMnrc程序，用蒙特卡罗方法仿真了环状束高功率微波源收集极的射线产生情况，典型输入束流参数为电压1 MV，电流10 kA，脉宽100 ns，重复频率100 Hz。仿真结果给出了X射线的谱分布和空间分布。据此估算了屏蔽X射线所需的墙壁衰减量。同时估算了X射线的天空散射因素以及房顶所需的衰减量。
- 高功率微波 /
- X射线屏蔽 /
- 蒙特卡罗方法 /
- 强流相对论电子束
Abstract: High power microwave research is moving into the high rep-rate regime and it will be common that an electron beam accelerator operates more than a million shots per year. As a result, accumulated bremsstrahlung X-ray produced by the electron beam collector is no longer negligible, and shielding is necessary for personnel safety. By using the BEAMnrc Monte-Carlo code, a typical collector for a ring beam usually used in HPM tube is simulated, which has beam voltage 1 MV, beam current 10 kA, pulse duration 100 ns and rep-rate 100 Hz. The results show the spectrum and spatial distribution of the X-ray generated at the collector. The attenuation factor of the X-ray is estimated from the simulation. The estimation of the skyshine radiation is also considered for the roof of the building.
- high power microwaves /
- X-ray shielding /
- Monte-Carlo /
- intense relativistic electron beam

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Figure 1. Geometry of the BEAMnrc input (unit: cm)

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Figure 2. Tracks of electrons (blue lines) and photons (green lines)

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Figure 3. Fluence distribution and spectrum of the photons

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Figure 4. Mass attenuation coefficient for ordinary concrete^[7]

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Figure 5. Suggested lead shielding scheme

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Figure 6. Skyshine diagram

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Table 1. Statistical fluence at scoring plane 1 m from the collector

zone	number of photons	fluence/cm^-2	photon energy/MeV	angle with z-axis/(°)
1	7.890E-04(1±3.56%)	6.355E-07(1±3.56%)	0.248(1±2.4%)	8.220(1±1.4%)
2	2.001E-03(1±2.24%)	5.580E-07(1±2.24%)	0.251(1±1.5%)	17.605(1±0.4%)
3	2.595E-03(1±1.96%)	4.637E-07(1±1.96%)	0.252(1±1.3%)	26.782(1±0.2%)
4	2.584E-03(1±1.97%)	3.592E-07(1±1.97%)	0.244(1±1.3%)	34.961(1±0.2%)
5	2.203E-03(1±2.13%)	2.629E-07(1±2.13%)	0.237(1±1.4%)	42.051(1±0.1%)
6	1.880E-03(1±2.30%)	2.027E-07(1±2.31%)	0.236(1±1.5%)	47.751(1±0.1%)
7	1.580E-03(1±2.51%)	1.590E-07(1±2.52%)	0.228(1±1.6%)	52.451(1±0.1%)
8	1.314E-03(1±2.76%)	1.259E-07(1±2.76%)	0.231(1±1.8%)	56.322(1±0.1%)
9	1.025E-03(1±3.12%)	9.493E-08(1±3.12%)	0.217(1±2.0%)	59.592(1±0.1%)
10	8.830E-04(1±3.36%)	7.958E-08(1±3.37%)	0.235(1±2.2%)	62.265(1±0.1%)
11	7.820E-04(1±3.57%)	6.928E-08(1±3.58%)	0.231(1±2.3%)	64.642(1±0.1%)
12	6.540E-04(1±3.91%)	5.699E-08(1±3.91%)	0.215(1±2.6%)	66.579(1±0.0%)
13	5.590E-04(1±4.23%)	4.807E-08(1±4.23%)	0.219(1±2.7%)	68.250(1±0.0%)
14	4.620E-04(1±4.65%)	3.931E-08(1±4.65%)	0.212(1±3.0%)	69.714(1±0.0%)
15	4.050E-04(1±4.97%)	3.431E-08(1±4.97%)	0.223(1±3.2%)	71.080(1±0.0%)
16	5.690E-04(1±4.19%)	2.542E-08(1±4.20%)	0.207(1±2.6%)	73.062(1±0.1%)

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参考文献(7)

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