In recent years,heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy.Usually,a very high uniformity in the irradiat...In recent years,heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy.Usually,a very high uniformity in the irradiation area is required for the extracted ion beams,which is crucial because it directly affects the experimental precision and therapeutic effect.Specifically,ultra-large-area and high-uniformity scanning are crucial requirements for spacecraft radiation effects assessment and serve as core specification for beamline terminal design.In the 300 MeV proton and heavy ion accelerator complex at the Space Environment Simulation and Research Infrastructure(SESRI),proton and heavy ion beams will be accelerated and ultimately delivered to three irradiation terminals.In order to achieve the required large irradiation area of 320 mm×320 mm,horizontal and vertical scanning magnets are used in the extraction beam line.However,considering the various requirements for beam species and energies,the tracking accuracy of power supplies(PSs),the eddy current effect of scanning magnets,and the fluctuation of ion bunch structure will reduce the irradiation uniformity.To mitigate these effects,a beam uniformity optimization method based on the measured beam distribution was proposed and applied in the accelerator complex at SESRI.In the experiment,the uniformity is successfully optimized from 75%to over 90%after five iterations of adjustment to the PS waveforms.In this paper,the method and experimental results were introduced.展开更多
离心机是岩土工程学科开展缩尺模型试验的主要装置,被广泛应用于降雨、滑坡等工程问题。开展了一系列无约束小球运动离心试验,基于双目立体视觉原理还原小球轨迹并验证了离心超重力下质点运动的控制方程。在此基础上对离心降雨模拟进行...离心机是岩土工程学科开展缩尺模型试验的主要装置,被广泛应用于降雨、滑坡等工程问题。开展了一系列无约束小球运动离心试验,基于双目立体视觉原理还原小球轨迹并验证了离心超重力下质点运动的控制方程。在此基础上对离心降雨模拟进行数值分析并提出4项降雨均匀性指标。分析表明,质量变化与非惯性系耦合作用会使得物体受到一项额外的作用力。离心超重力下the Green Mist喷嘴模拟的降雨的空间和统计分布特征会在空气阻力和非惯性系作用下发生显著改变。降雨均匀性指标对于确定喷嘴阵列布置具有指导意义,以研究工况为例,2×2的the Green Mist喷嘴阵列沿边坡长度和宽度方向的喷嘴覆盖面积重叠率的推荐值分别为60.47%,55.36%。展开更多
基金Supported by National Key R&D Program of China(2019YFA0405400)。
文摘In recent years,heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy.Usually,a very high uniformity in the irradiation area is required for the extracted ion beams,which is crucial because it directly affects the experimental precision and therapeutic effect.Specifically,ultra-large-area and high-uniformity scanning are crucial requirements for spacecraft radiation effects assessment and serve as core specification for beamline terminal design.In the 300 MeV proton and heavy ion accelerator complex at the Space Environment Simulation and Research Infrastructure(SESRI),proton and heavy ion beams will be accelerated and ultimately delivered to three irradiation terminals.In order to achieve the required large irradiation area of 320 mm×320 mm,horizontal and vertical scanning magnets are used in the extraction beam line.However,considering the various requirements for beam species and energies,the tracking accuracy of power supplies(PSs),the eddy current effect of scanning magnets,and the fluctuation of ion bunch structure will reduce the irradiation uniformity.To mitigate these effects,a beam uniformity optimization method based on the measured beam distribution was proposed and applied in the accelerator complex at SESRI.In the experiment,the uniformity is successfully optimized from 75%to over 90%after five iterations of adjustment to the PS waveforms.In this paper,the method and experimental results were introduced.
文摘离心机是岩土工程学科开展缩尺模型试验的主要装置,被广泛应用于降雨、滑坡等工程问题。开展了一系列无约束小球运动离心试验,基于双目立体视觉原理还原小球轨迹并验证了离心超重力下质点运动的控制方程。在此基础上对离心降雨模拟进行数值分析并提出4项降雨均匀性指标。分析表明,质量变化与非惯性系耦合作用会使得物体受到一项额外的作用力。离心超重力下the Green Mist喷嘴模拟的降雨的空间和统计分布特征会在空气阻力和非惯性系作用下发生显著改变。降雨均匀性指标对于确定喷嘴阵列布置具有指导意义,以研究工况为例,2×2的the Green Mist喷嘴阵列沿边坡长度和宽度方向的喷嘴覆盖面积重叠率的推荐值分别为60.47%,55.36%。
