靶材料面密度用β射线测量的定标问题

Calibration in measurement of ICF target material areal density using β-ray

惯性约束聚变靶材料面密度及其均匀性分布可以通过β射线束透射法进行测量,要完成这一测量,需首先用一系列面密度已知、组成成分与待测材料相同的标准材料对测量装置进行刻度。针对惯性约束聚变靶材料一类还处于研制阶段的新材料的密度测量,提出了用成分相近的材料作为替代标准进行刻度的方法,并用蒙特卡罗方法模拟计算了不同能量电子穿过不同材料的透射率,得到了这种刻度方法对测量结果带来的误差大小,用纸作标准测量CH泡沫靶材料的误差只有百分之几,这一误差在实际测量中可以由蒙特卡罗模拟方法得到修正。该刻度方法解决了惯性约束聚变靶材料一类新材料面密度用β透射法测量中的定标问题。

ICF target material areal density and its distribution can be measured by counting beta particles passing through the material. It is necessary to calibrate the areal density measuring device using a series of standard materials with known areal densities and the same components with the materials to be analyzed. For the density measurement of a kind of ICF target material the calibrating method is proposed. This calibrating method uses the approximate, materials with composition of the ICF target material as the standard material. The transmissivity of beta particles possessing different energy can be simulated and computed by Monte-Carlo method when they pass different materials. The corresponding error to the measuring result is also obtained. The error is only several percent using paper sheet as the standard material to measure CH foam materials and can be revised by means of Monte-Carlo method.