可携式放射源定向测量仪探头设计

摘要

针对大部分周围剂量当量监测仪和个人剂量当量监测仪不能给出γ射线入射方向的情况，设计了一种简易的、新型的可携式放射源定向测量仪探头。定向测量仪探头由ф76．2 mm ×76．2 mm NaI（Tl）晶体和一个特殊形状的铅屏蔽层组成，其中铅的厚度为20 mm。探头设计时用MCNPX2．5程序对能量响应和角度响应进行了模拟计算，计算结果表明该探头对γ射线能量没有依赖性，角度响应的计算不确定度小于4°。该探头可用于放射源的搜寻、核电站常规泄漏监测以及核应急事故热区定位等现场作业。%Because most detectors used for measuring ambient gamma radiation and personal dose equivalent are unable to give the direction information of gamma rays ,a simple and new type of portable direction finder for ra-diation sources is designed .This detector consists of a 76.2 mm ×76.2 mmфNaI( Tl) scintillator and a spe-cially shaped lead shield of 20 mm thick.The design and calculation of this detector were taken by using MC -NPX2.5 Monte Carlo code, which shows that this detector has no dependence on energy and the uncertainty of the estimated incident gamma ray angles is within 4°.This detector will be useful to carry out searching for radi-ation sources such as radioisotopes and radioactive contaminations and monitoring of nuclear power plants or ra -diation facilities during the site work .