_37_Ar测量系统的本底降低技术.pdf

435 Vol. 43, N o. 5 20095 Atomic Energy Science and T echnology M ay 2009 37 Ar 向永春, 龚 建, 李 伟, 卞直上, 郝樊华, 王红侠, 王 茜 ( , 62 900) 37 : Ar , M CNP , , , : , 37 75% , , Ar 37 : Ar; ; ; : O57 . 32 :A : 000693 ( 2009) Decreasing Background of 37 Ar Measurement System XIAN G Yongchun, GONG Jian, LI Wei, BIAN Zhishang, HAO Fanhua, WANG H ongxia, WANG Qian ( China A cad emy of E ng ineer ing P hys ics , P . O. B ox 9 92 4, M iany ang 62 900, China) Abstract: The background components of the 37 Ar measurement system w ere analyzed from their radioactive origins. Both the backgrounds of the previous shield and the new 37 improved one w ere calculated by M CNP code. According to the scene of using the Ar measurement system, the main w ork w as focused on optimizing its structure and machi ning . T he background of the improved shield falls to 75% that of the previous one. The test results are consistent w ith the calculated results. So the detection sensitivity of the 37 Ar measurement system is increased further. Key words: 37 Ar; background; shield; onsite inspection 37 , , Ar 40 37 [ ] Ca( n, ) Ar , 37 37 Ar, , A r 2003 37 37 [ 23] , Ar A r , CT BTO ( CTBTO, Comprehensive Nu , clearT estBan T reaty