GEANT4接续计算方法以及在GRH系统优化设计中的应用  

Continuation calculation methods of GEANT4 and its application in optimization design of GRH system

作　　者：刘斌[1] 胡华四[2] 吕焕文[1] 李兰[1] 

机构地区：[1]中国核动力研究设计院核反应堆系统设计技术重点实验室,成都610041 [2]西安交通大学核科学与技术学院,西安710049

出　　处：《核技术》2017年第7期23-28,共6页Nuclear Techniques

基　　金：国家自然科学基金(No.10975113);陕西省自然科学重点基金(No.S2015YFJZ0197)资助~~

摘　　要：遗传算法调用GEANT4优化设计方法应用于气体切伦科夫探测器GRH(Gamma Reaction History)系统设计过程可有效提高探测器指标,然而GEANT4程序计算耗时。本文研究了GEANT4程序的接续计算方法,采用函数拟合方式和文件读入的方式进行了接续计算源描述,采用文件读入的方式接续计算结果与直接计算结果吻合良好,效率相差1.4%,时间谱半高宽相差2.1%。采用接续计算方法使得整体优化时间下降50%以上,提高了计算效率。该接续计算方法也可应用于其他采用GEANT4直接模拟收敛困难的计算问题。Background： Gamma reaction history （GRH） is becoming important for inertial confinement fusion （ICF） diagnostic. The traditional design for GRH is by optical-ray-tracing method which is based on geometrical optics. However, the detector performances, such as detection efficiency and time response, are hard to improve as a result of lacking precise considerations of energy and angular distributions of secondary electrons. The optimization method genetic algorithm （GA） combining with GEANT4 can be used to enhance the detector performances during the design process. However, the computational time consumption of GEANT4 is great. Purpose： In order to accelerate the GEANT4 program, two continuation calculation methods, function fitting method and file read method, have been established. Methods： For the function fitting method, distributions of positions, directions, time and wavelengths of Cherenkov photons are fitted as functions, and then the fitted functions are sampled in GEANT4 program. For the file read method, positions, directions, time, and energy of Cherenkov photons are stored as a matrix, and then the matrix is read in GEANT4 program as the continuation source. Results： The difference between the acceleration efficiencies of the two methods is small. The file read method is more accurate than the function fitting method. Time spectrum of Cherenkov photons with the file read continuation source agrees well with time spectra calculated with 16.7-MeV gamma source. Deviations of the efficiency and full width half maximum （FWHM） are 1.4% and 2.1%. Conclusion： The computational time of GEANT4 can be reduced by more than 50%. Moreover, the continuation calculation method can be applied to other GEANT4 simulation problems with convergence difficulty by direct simulation.

关 键 词：GEANT4模拟 接续计算 氘氚聚变 气体切伦科夫探测系统 

分 类 号：TL657[核科学技术—核技术及应用]