载能α粒子诱发氮气荧光CCD成像效果模拟  

Simulation of Imaging Effect of Nitrogen Fluorescence CCD Induced by

作　　者：王权晓 司书尧 李枝恒 秦李鑫 乔宇洁 王健[2] 方开洪[1,2,3] WANG Quanxiao;SI Shuyao;LI Zhiheng;QIN Lixin;QIAO Yuejie;WANG Jian;FANG Kaihong(School of Nuclear Science and Technology,Lanzhou University,Lanzhou,730000,China;Institute of Science and Technology,China National Nuclear 404 Corporation,Jiayuguan 735100,China;Lanzhou 505 Nuclear Safety Technology Research Center,Lanzhou City,730000,Chin)

机构地区：[1]兰州大学核学学院,兰州730000 [2]中核四〇四有限公司科学技术研究院,嘉峪关735100 [3]兰州五零五核安全技术研究中心,兰州730000

出　　处：《核电子学与探测技术》2023年第4期790-796,共7页Nuclear Electronics & Detection Technology

基　　金：“中核集团2021年青年英才科研项目-76”项目资助。

摘　　要：通过探测载能α粒子激发空气中氮气而产生的荧光,实现对核应急或未知场所α表面污染强度的远程初判,该方法具有广阔的应用前景。其中,荧光产额和成像效果是关键性指标。为了研究α粒子激发空气中氮气的荧光产额和成像效果,以特定型号CCD相机为参考,结合Geant4软件,建立了光传输和收集模型,并对成像效果的信噪比、分辨率、遮掩效果等进行了模拟。结果表明,随着测量时间的增加,信噪比收益越来越低,且强源相比于弱源,要得到较高信噪比的图像更容易;α粒子诱发荧光的成像分辨率很高,成像结果的边界基本等同于源的尺寸;强源对其附近弱源存在掩盖效应,这一效应随着到强源距离的增加愈发不明显,且在超出α粒子的射程范围后,不再受到影响。该模拟结果对后续成像系统工程技术中CCD相机选型、可测活度下限、成像分辨率等关键性指标提供了重要参考。By detecting the ultraviolet fluorescence produced by de-excitation of nitrogen molecules,excited by alpha ray,in air,it realizes the remote preliminary judgment of the intensity ofαsurface contamination in nuclear emergency or unknown sites,which has a broad application prospect.Moreover,the fluorescence yield and imaging effect are the key performance indicators.In order to study the fluorescence yield and imaging effect,this paper takes the indicators of a specific model of EMCCD camera as a reference and establish a model of light transmission,collection and imaging,and simulates the signal-to-noise ratio,imaging resolution,and imaging effect.The results show that:(1)as the measurement time increasing,the signal-to-noise gain is getting lower and lower;and it is much easier to get a higher signal-to-noise ratio for strong sources compared with weak.(2)the imaging resolution ofα-particle induced fluorescence is very high,and the boundaries of the image are basically equivalent to the size of the source.(3)A strong source will obscure a weak source within its alpha ray range,and this effect becomes less obvious as the distance increases.The simulation results provide an important reference for the selection of CCD camera,the lower limit of measurable activity,the imaging resolution and other key indexes in the subsequent imaging system engineering technology.

关 键 词：GEANT4 氮气荧光 CCD成像 

分 类 号：O4-33[理学—物理]