Mobit P N, Nahum A E, Mayles P
Joint Department of Physics, Institute of Cancer Research, Sutton, UK.
Phys Med Biol. 1996 Jun;41(6):979-93. doi: 10.1088/0031-9155/41/6/003.
The energy correction factor of LiF thermoluminescent dosemeters (TLDs) calibrated in Co-60 gamma-rays and used for measurements in megavoltage electron beams has been determined experimentally and theoretically using Monte Carlo simulations. The experiments show that the energy correction factor of 1 mm thick TLD-100 has an average for both rods and chips which varies from 1.036 +/- 1.3% (1 SD) for 4 MeV electron beams to 1.021 +/- 1.3% (1 SD) for 20 MeV electron beams for measurement performed at dmax in PMMA (Perspex). The results of the Monte Carlo simulations were within 0.6% of the experimental results and ranged from 1.041 +/- 0.9% (1 SD) for 2 MeV electrons to 1.028 +/- 0.8% (1 SD) for 20 MeV electron beams. There was no significant difference in the energy correction factors of LiF TLDs irradiated in PMMA or water by Monte Carlo simulation and experiments. Differences in the energy correction factors between rods and chips of the same thickness were negligible both in the experiments and in Monte Carlo calculation. When the diameter of the LiF TLD micro-rod was increased from 1 to 5 mm, the simulated energy correction factors increased by as much as 5% over this energy range. The energy correction factors changed by up to 4% for irradiation of TLD at depths other than at dmax for a 5 MeV mono-energetic electron beam.
已通过实验和使用蒙特卡罗模拟从理论上确定了在钴 - 60伽马射线中校准并用于兆伏电子束测量的氟化锂热释光剂量计（TLD）的能量校正因子。实验表明，对于在聚甲基丙烯酸甲酯（有机玻璃）中dmax处进行的测量，1毫米厚的TLD - 100的能量校正因子，对于棒状和芯片状的平均校正因子，在4兆电子伏电子束下为1.036±1.3%（1标准差），在20兆电子伏电子束下为1.021±1.3%（1标准差）。蒙特卡罗模拟结果在实验结果的0.6%以内，范围从2兆电子伏电子束的1.041±0.9%（1标准差）到20兆电子伏电子束的1.028±0.8%（1标准差）。通过蒙特卡罗模拟和实验，在聚甲基丙烯酸甲酯或水中辐照的氟化锂TLD的能量校正因子没有显著差异。在实验和蒙特卡罗计算中，相同厚度的棒状和芯片状的能量校正因子差异都可以忽略不计。当氟化锂TLD微棒的直径从1毫米增加到5毫米时，在此能量范围内模拟的能量校正因子增加多达5%。对于5兆电子伏单能电子束，在dmax以外的深度辐照TLD时，能量校正因子变化高达4%。
