快中子堆n,γ混合场中γ光子注量的测量研究

Investigations of the photon fluences in various n+γ mixed fields in the fast neutron reactor

用热释光探测器对快堆堆外n ,γ混合场进行了区分测量 ,结果表明 :该方法可有效的检测出n ,γ混合场的γ成分 ;为了更较精确地测量快堆n ,γ混合场γ光子注量 ,提出了采用新配方的热释光探测器LiFTLD(6 LiF ,7LiF各占5 0 % )与6 LiFTLD成对使用的方法 .考虑到LiFTLD对中子吸收剂量的响应存在LET效应 ,对LiF(Mg ,Cu ,P)TLD进行了中子响应的LET效应因子RLET的实验测定 (RLET≈ 0 0 5 ) ,在此基础上 ,对6 LiF 7LiFTLD的成对使用测量快中子堆的n ,γ混合场中光子注量的方法进行了实验研究 .实验结果表明 ,混合场中的中子在7LiF(Mg ,Cu ,P)中产生的热释光量 (TL)占n ,γ产生的总TL的 8 1%— 17 1% .实验结果表明该方法是行之有效的 .为钝化中子谱的不确定性所致的影响 ,进一步提高γ光子注量测量结果的精度 ,提出了采用新配方的LiFTLD(6 LiF ,7LiF各占 5 0 % )与6 LiFTLD成对使用测量快堆n ,γ混合场γ光子注量的方法 .

The LET factors R LET ( R LET ≈0 05) of neutron response for LiF(Mg,Cu,P)TLD have been determined experimentally due to the existing LET effects of the response for LiFTLD to neutron absorbed dose.Based on the data,one experimental method to define the photon fluence in various n+γ mixed fields in the fast neutron reactor with coupled 6LiF 7LiFTL detectors has been checked.The experimental results show that the ratios of the TL due to the effect of neutrons in 7LiF(Mg,Cu,P)to the total TL due to the combined effects of the γ rays and neutrons are between 8 1% and 17.1%.In order to reduce the effect caused by the uncertainty of the neutron spectra and improve the accuracy of the measurement for the photon fluence,we propose a new LiFTLD,in which there are 50% 6LiF and 50% 7LiF.It is coupled with a 6LiFTLD to measure the photon fluence in the n+γ mixed fields.