CdWO_4、CsI(Tl)和PbWO_4晶体在9MeV工业CT中探测效率比较

Detection Efficiency Study of CdWO_4,CsI(Tl) and PbWO_4 for 9 MeV Industrial CT

为找出更适合于9 MeV加速器工业CT系统应用的闪烁晶体,对常用的工业CT闪烁晶体CdWO4、CsI(Tl)、PbWO4在系统上进行了实验。利用CCD相机、准直器、闪烁晶体等组成探测系统,在同一实验条件下对截面积相同,长度为25 mm～45 mm的CsI(Tl)、CdWO4、PbWO4晶体在同一位置的探测计数进行反复测量,得到不同晶体长度对应探测计数图。实验结果表明:不同晶体材料探测效率不同,闪烁晶体在未包裹反光膜状态,35 mm长度CsI(Tl)探测效率最好,而在包裹反光膜状态下45 mm长度CdWO4探测效率最好。

To find out the more applicable scintillant cystal for 9 MeV accelerator industrial CT system,experiments were carried out with such scintillants as CdWO4、CsI（Tl）、PbWO4.The detection system was set up with CCD camera,collimator and scintillant.Detection counts of 25 mm to 45 mm CsI（Tl）,CdWO4 and PbWO4 were taken under the same experiment conditions.After repetitious measurements,the diagram of detection efficiency to scintillant length was done.The result turns out that detection efficiency varies with different scintillant crystals.When upwrapped in reflector film,35 mm length CsI（Tl） gets the best detection accounts;While wrapped in reflector film,45 mm CdWO4 gets the best.