Monte Carlo estimation of average energy required to produce an ion pair in noble gases by electrons with energies from 1 keV to 100 MeV

This paper describes the results of Monte Carlo estimation of the average energy W required to produce an ion pair in five noble gases by fast electrons. The ENDF/B-VI.8 library was used as the source of electroionization and atomic excitation cross sections for electron energies above 1 keV, as well as the source of all other types of electron and photon interaction cross sections for all energies. The low-energy electroionization and atomic excitation cross sections were taken from three data-sets: ENDF/B-VI.8 and two data-sets posted on the LXCat website (www.lxcat.net), i.e., BIAGI-v8.9 and SIGLO. Calculations were done using MCNP6 and a similar open-source program MCNelectron (http://web.vu.lt/ff/a.poskus/mcnelectron/). By comparing the calculated W-values with experimental ones, it is shown that replacement of the low-energy part of ENDF/B-VI.8 electroionization and excitation cross section data by LXCat data causes a significant improvement of accuracy of the calculated W-value. This accuracy can be improved even more by interpolation between the low-energy LXCat cross sections and high-energy ENDF/B-VI.8 cross sections. It is concluded that the value of W obtained by Monte Carlo simulation using different sets of low-energy electron interaction cross sections can be used as one of the criteria for evaluating accuracy of those data-sets. (author)