Investigation of Applicability of Pure Propane Gas for Microdosimetry at Neutron Fields: A Monte Carlo Study

Abstract

Applicability of pure propane gas for microdosimetric measurements in neutron fields was investigated using the FLUKA Monte Carlo code. Monoenergetic neutrons in the energy range 1 keV−20 MeV and the ISO-neutron sources such as 241Am-Be, 241Am-B, 252Cf and 252Cf + D2O were considered in the present study. The tissue-equivalent proportional counter (TEPC) simulated in the study was LET-1/2 (by Far West Technology) with site sizes 1, 2 and 8 μm. The study demonstrates that for a given site size, the TEPC filled with tissue-equivalent propane and pure propane gases produce similar microdosimetric distributions when the density of pure propane gas is lowered appropriately. For the ISO-neutron sources, the density of propane gas requires scaling by a factor 0.85. For the monoenergetic neutrons, depending upon the neutron energy, the values of scaling factors are in the range of 0.58–0.93.

Microdosimetry-based investigation of biological effectiveness of 252Cf brachytherapy source: TOPAS Monte Carlo study

“…The interactions of neutrons with tissue or tissue equivalent medium are discussed in details elsewhere (Rivard et al 1999, Chattaraj et al 2019a. Neutrons are thermalized through elastic scattering with hydrogen nuclei of water.…”

“…Note that Flair is the Advanced Graphical User Interface for FLUKA code. FLUKA has been well benchmarked for calculation of the microdosimetric distributions of neutron sources (Fasso et al 2001, Rollet et al 2004, Zhang et al 2014, Chattaraj et al 2019a. The TOPAS-based microdosimetric calculations as described in Case 2 were repeated using FLUKA for R = 1-5 cm (see figure 4(b) for simulation setup).…”

“…Although microdosmetric studies on 252 Cf neutron sources related to radiation protection are reported (Rollet et al 2004, Zhang et al 2014, Chattaraj et al 2019a, a similar study for a 252 Cf brachytherapy source has not been reported in the literature. The present study is aimed at calculating the biological effectiveness of a 252 Cf brachytherapy source as a function of radial distance (R) in water phantom using microdosimetric technique.…”