With a rapidly increasing demand and widespread use of radiotherapy treatment, the subject area of in-vivo real time dose rate dosimeters has become a significant area of study. An embedded structure fiber-optic radia...With a rapidly increasing demand and widespread use of radiotherapy treatment, the subject area of in-vivo real time dose rate dosimeters has become a significant area of study. An embedded structure fiber-optic radiation dosimeter has proved to be a promising candidate to fulfil this role because of its high SNR (signal-to-noise ratio) and excellent light conversion efficiency. In this paper, the properties of this kind of dosimeter with respect to different SSD (Source to Surface Distance) and beam field size in a clinical Linac are studied. The characteristics of the dosimeter were evaluated by the sensor’s output intensity response in these conditions.展开更多
针对6061铝合金的电子束选区熔化(Selective Electron Beam Melting,SEBM)过程,采用ANSYS构建了温度场仿真三维有限元模型。考虑材料的热物性参数随温度的变化特性,通过高斯面热源在粉末床上移动,研究了电子束功率、扫描速度和铝合金预...针对6061铝合金的电子束选区熔化(Selective Electron Beam Melting,SEBM)过程,采用ANSYS构建了温度场仿真三维有限元模型。考虑材料的热物性参数随温度的变化特性,通过高斯面热源在粉末床上移动,研究了电子束功率、扫描速度和铝合金预热温度对熔池尺寸、熔池热历史的影响,为6061铝合金电子束选区增材制造工艺参数的选择提供理论依据。研究结果表明:熔池宽度、熔池深度随着电子束功率、预热温度的增大而增大;输入线能量小于0.19 J/mm时,熔池深度、宽度均随着扫描速度的增大而减小,熔池长度随扫描速度的增大而增大;当输入线能量大于0.19 J/mm时,熔池深度、宽度均随着扫描速度的增大而增大,但增大速率减小,熔池长度随扫描速度的增大而减小。电子束功率是影响熔池冷却速率的主要因素。不同扫描路径的粉末层温度分布不同,采用合理的扫描路径可使得整个零件的热分布更加均匀。展开更多
文摘With a rapidly increasing demand and widespread use of radiotherapy treatment, the subject area of in-vivo real time dose rate dosimeters has become a significant area of study. An embedded structure fiber-optic radiation dosimeter has proved to be a promising candidate to fulfil this role because of its high SNR (signal-to-noise ratio) and excellent light conversion efficiency. In this paper, the properties of this kind of dosimeter with respect to different SSD (Source to Surface Distance) and beam field size in a clinical Linac are studied. The characteristics of the dosimeter were evaluated by the sensor’s output intensity response in these conditions.
