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| The Absolute Measurement for 2πα and 2πβ Particle Emission Rate |
| LIANG Jun-cheng1,LI Qi2,1,LIU Jia-cheng3,YANG Zhi-jie1,4 |
1. National Institute of Metrology, Beijing 100029, China
2. Guangdong Provincal Insititute of Metrology, Guangzhou Guangdong 510405, China
3. Nuclear and Radiation Safety Center of Ministry of Environment Protection, Beijing 100082, China
4. China University of Geosciences, Beijing 100083, China |
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Abstract Based on a large-area gas flow proportional counter, a 2π alpha and 2π beta particle emission rate measurement system is established. Performance test is executed and the results show that the plateau length of 600～800V, the optimal average plateau incline of 0.2%/100V for alpha plane sources, and the plateau length of 350～400V, the optimal average plateau incline of 0.23%/100V for beta plane sources are achieved. Uniformity for counting is measured by 239Pu alpha point source to be 0.45% in the central region of 100mm×150mm. Corrections including the background, dead time and the discrimination threshold are executed, and the absolute measurement of particle emission rate for the alpha and beta plane sources are realized. The expanded uncertainty of measurement result are better than 0.9% (k=2) for alpha sources and better than 1.1% (k=2) for beta sources. Comparisons of emission rate of 9 importing sources including 233U and 241Am etc. are executed between 2πα、2πβ primary standard equipment and new built emission rate measurement system, and the measurement results are equivalent in expanded uncertainties limits.
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Received: 02 January 2015
Published: 27 January 2016
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［1］ISO 8769 Reference sources—Calibration of surface contamination monitors—alpha, beta and photon emitters［S］. 2010.
［2］Wuu J L, Yuan M C, Su S H, et al. The alpha and beta emitter measurement system in INER［J］. Applied Radiation and Isotopes, 2002, 56(s1-2): 261-264.
［3］King L E, Hutchinson J M R, Unterweger M P. A new large-area 2π proportional counting system at NIST［J］. Applied Radiation and Isotopes, 2008, 66(6): 877-880.
［4］Hutchinson J M R, Bright S J. The NBS large-area alpha-particle counting systems［J］. J Res NBS, 1987, 92(5): 311.
［5］杜向阳,饶贤明,韩淑萍,等.GFM-Ⅱ型大面积α、β污染测量仪［J］. 核电子学与探测技术, 2002, 22(4): 357-361.
［6］庹先国,穆克亮,李向阳,等. 高探测效率氚测量仪［J］. 核技术, 2007, 30(4):388-390.
［7］杨立涛, 吴连生,陈超峰等.流气式正比计数器对90Sr-90Y效率刻度和水样加标分析研究［C］//中国核学会辐射防护分会. 2013年学术年会. 厦门:2013.
［8］孙凤荣, 黑东炜,王群书,等. 软X射线晶体标定系统研制［J］.核电子学与探测技术,2010,30(12):1598-1601.
［9］张伟华, 王志强, 肖雪夫, 等. 组织等效正比计数器结构优化设计［J］. 原子能科学技术, 2014, 48(5): 930-933.
［10］李琦, 常永福, 解峰, 等. 一个用于 4πβ+ 4πγ 活度测量的小型流气式正比计数器［J］.核电子学与探测技术, 2005, 25(2): 131-133.
［11］Charpak G. Evolution of the automatic spark chambers［J］.Annual Review of Nuclear Science, 1970, 20(1): 195-254.
［12］Charpak G, Sauli F. Multiwire proportional chambers and drift chambers［J］. Nuclear Instruments & Methods, 1979, 162: 405-428.
［13］Hutchinson J. Particle Counting in Radioactivity Measurements［R］. ICRU Report 52, 1995. |
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2016, Vol. 37 
