The collection efficiency of monitor parallel plate ionization chambers is the main uncertainty in the beam control of pencil beam scanning systems.Existing calculation methods for collection efficiency in photon or p...The collection efficiency of monitor parallel plate ionization chambers is the main uncertainty in the beam control of pencil beam scanning systems.Existing calculation methods for collection efficiency in photon or passive scattering proton systems have not considered the characteristics of non-uniform charge density in pencil beam scanning systems.In this study,Boag’s theory was applied to a proton pencil beam scanning system.The transverse distribution of charge density in the ionization chamber was considered to be a Gaussian function and an analytical solution was derived to calculate collection efficiency in the beam spot area.This calculation method is called the integral method and it was used to investigate the effects of beam parameters on collection efficiency.It was determined that collection efficiency is positively correlated with applied voltage,beam size,and beam energy,but negatively correlated with beam current intensity.Additionally,it was confirmed that collection efficiency is improved when the air filling the monitor parallel plate ionization chamber is replaced with nitrogen.展开更多
本文较为系统地阐述了发展空间太阳能发电卫星(space solar power satellite, SSPS)的几个问题.首先,论述了发展SSPS对世界人类从根本上解决能源危机,尤其是对我国生存与发展的极端重要性.其次,对聚光与非聚光两大类空间太阳能发电卫星...本文较为系统地阐述了发展空间太阳能发电卫星(space solar power satellite, SSPS)的几个问题.首先,论述了发展SSPS对世界人类从根本上解决能源危机,尤其是对我国生存与发展的极端重要性.其次,对聚光与非聚光两大类空间太阳能发电卫星的几个典型设计方案,从功质比(即单位质量所产生的电能)指标、工程实现、可靠性等方面,分析了它们的优缺点.再者,对作者团队2014年提出的SSPS-OMEGA方案的近期研究进展作了较为详细的讨论.最后,就本领域近期进展与未来需注意的几个理论与技术问题,提出了相应的观点.展开更多
文摘The collection efficiency of monitor parallel plate ionization chambers is the main uncertainty in the beam control of pencil beam scanning systems.Existing calculation methods for collection efficiency in photon or passive scattering proton systems have not considered the characteristics of non-uniform charge density in pencil beam scanning systems.In this study,Boag’s theory was applied to a proton pencil beam scanning system.The transverse distribution of charge density in the ionization chamber was considered to be a Gaussian function and an analytical solution was derived to calculate collection efficiency in the beam spot area.This calculation method is called the integral method and it was used to investigate the effects of beam parameters on collection efficiency.It was determined that collection efficiency is positively correlated with applied voltage,beam size,and beam energy,but negatively correlated with beam current intensity.Additionally,it was confirmed that collection efficiency is improved when the air filling the monitor parallel plate ionization chamber is replaced with nitrogen.
文摘本文较为系统地阐述了发展空间太阳能发电卫星(space solar power satellite, SSPS)的几个问题.首先,论述了发展SSPS对世界人类从根本上解决能源危机,尤其是对我国生存与发展的极端重要性.其次,对聚光与非聚光两大类空间太阳能发电卫星的几个典型设计方案,从功质比(即单位质量所产生的电能)指标、工程实现、可靠性等方面,分析了它们的优缺点.再者,对作者团队2014年提出的SSPS-OMEGA方案的近期研究进展作了较为详细的讨论.最后,就本领域近期进展与未来需注意的几个理论与技术问题,提出了相应的观点.
