Flores-Mancera Miguel Angel, Villarrubia John S, Massillon-Jl Guerda
Instituto de Física, Universidad Nacional Autónoma de México, 04510 Coyoacán, México City, México.
Microsystems and Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
ACS Omega. 2020 Feb 17;5(8):4139-4147. doi: 10.1021/acsomega.9b03872. eCollection 2020 Mar 3.
We report new calculations, which include the influence of the band gap and exciton states, of the electron inelastic mean free path (IMFP) for liquid water, LiF, CaF, and AlO from the band gap to 433 keV. Among compounds, liquid water is the most studied due to its role in radiobiological research, whereas LiF and CaF are the most widely used thermoluminescent dosimeters in environmental monitoring and medical and space dosimetry. Due to its sensitivity, the optically stimulated luminescent dosimeter, AlO, has recently begun to be used for personnel monitoring. Previous treatments have modified the integration domain to consider the indistinguishability between the incident electron and the ejected one or the bandgap energy for nonconductors but not to accommodate exciton states within the band gap, and no published IMFP data are available for CaF. Our calculation was carried out using an electron-beam-solid-state interaction model through the relativistic full Penn algorithm. Integration limits that consider the band gap, the valence band width, and exciton interactions have been used. The results suggest that, at electron energies below 100 eV, the different choices of models for integration limits and the exciton interaction can affect the IMFP by 9-29%. At higher energies, the differences associated with the choice of energy-loss function and other input parameters are around 2.5-7.5%.
我们报告了新的计算结果，该计算包括带隙和激子态的影响，涉及从带隙到433 keV能量范围内液态水、LiF、CaF和AlO中电子的非弹性平均自由程（IMFP）。在这些化合物中，液态水因其在放射生物学研究中的作用而受到最多研究，而LiF和CaF是环境监测以及医学和空间剂量测定中使用最广泛的热释光剂量计。由于其敏感性，光激发发光剂量计AlO最近已开始用于人员监测。先前的处理方法修改了积分域，以考虑入射电子和出射电子之间的不可区分性或非导体的带隙能量，但未考虑带隙内的激子态，并且目前尚无关于CaF的已发表IMFP数据。我们的计算是通过相对论性全彭算法，使用电子束 - 固态相互作用模型进行的。采用了考虑带隙、价带宽度和激子相互作用的积分限。结果表明，在电子能量低于100 eV时，积分限和激子相互作用模型的不同选择可使IMFP变化9 - 29%。在较高能量下，与能量损失函数和其他输入参数选择相关的差异约为2.5 - 7.5%。
