石英和长石颗粒中^(87)Rb β剂量和吸收分数的蒙特卡罗计算

Monte Carlo Calculation of Absorbed Dose and Absorbed Fraction for ^(87)Rb β Particles in Quartz or Feldspar Grains

用EGSnrc蒙特卡罗程序模拟计算大小不同的石英和长石颗粒中87Rbβ粒子的吸收剂量,讨论颗粒大小对吸收剂量和吸收分数的影响。石英和长石颗粒直径为5~100 000μm,放于同样成分的无限大均匀介质中,87Rb放射性核素均匀分布于颗粒中。结果表明,颗粒大小对87Rbβ吸收剂量和吸收分数的影响非常明显,直径约为50μm和100μm的颗粒吸收分数分别约为30%和50%,但石英颗粒与钾长石颗粒之间吸收分数的差异不大。

The EGSnrc Monte Carlo code was used to calculate the absorbed dose and the absorbed fractions for ^87 Rb β particles in quartz or K-feldspar grains. The ^87 Rb radionuclides distributed uniformly in a quartz or K-feldspar grain. The grain embedded in an infinite uniform medium containing the same composition as the grain. The diameter of the spherical grain ranged from 5 to 100 000 μm. Results show that the absorbed dose and the absorbed fraction for ^87 Rb β particles depend strongly on the size of the quartz or the K-feldspar grain.The absorbed fractions of the grains with diameters of about 50 and 100 μm are about 30% and 50%,respectively. But the differences between the absorbed fractions of the quartz grains and that of the K-feldspar grains are quite small.