【摘要】 造钚率实验研究中需要测量贫化铀活化片发射的277.6 keVγ射线,活化片对此γ射线具有一定自吸收作用,需要对其进行修正。用面源法和体源法开展了自吸收理论的蒙德卡罗模拟计算,结果显示:探测距离为9 cm时,两种方法的偏差小于1.3%。用243Am面源、贫化铀活化片和HPGe探测器开展了277.6 keVγ射线自吸收实验研究,得到了不同厚度贫化铀活化片对277.6 keVγ射线自吸因子,实验结果与理论模拟偏差小于2.5%。更多还原

【Abstract】 [Background] γ-ray of 277.6 keV needs to be measured in plutonium production pates experiment. Selfabsorption effect of depleted uranium activated foils will affect the accuracy of the measuring results.[Purpose] This study aims to correct the γ-ray self-absorption effect of the activation foils in the plutonium production rates experiment. [Methods] First of all, plane source method and substance method were applied to MCNP(Monte Carlo N Particle Transport Code) to simulate the self-absorption theory, and results at various detection distance were obtained. Then experiments using 243 Am plane radioactive source, depleted uranium foils and the HPGe detector were carried out to obtain self-absorption factors of 277.6 keV gamma-ray for depleted uranium activated foils with different thickness. [Results] The deviation of these two methods for simulation calculation of self-absorption factor is less than 1.3% at detection distance of 9 cm. The deviation between experimental measurement and simulation computation is less than 2.5% for depleted uranium foils with different thickness. [Conclusion] The reliability of theoretical simulation is proved by the verification between experiment and theory in this study. Hence the selfabsorption correction factors of samples under different measurement models can be obtained by theoretical simulation in the plutonium production rates experiment.更多还原