Experimental verification of dosimetry predictions of bremsstrahlung attenuation as a function of material and electron energy

Abstract

Dose attenuation with depth in an absorber of on-axis bremsstrahlung generated from an electron target is measured and shown to agree within f9% with Monte Carlo predictions as afunction ofabsorber material (Al,Fe,Pb) and incidentelectronbeam energy (5.5-25.1 MeV). For this on-axis bremsstrahlung, 1 to 5 g/cm2 of upstream and 0.2 to 1 @cm2 of downstream AI buffer is sufficient to provide electron equilibration for CaF2:Mn thermoluminescent dosimeters P D s ) over the measured energy range of 5.5 to 25.1 MeV, respectively. Once "effective" equilibration has been established, an expression of the form DA/Q = c,v4e-GvoA, can be used to predict the dose-area (DA) product per absorbed beam charge (Q) at a given incident beam energy (V) in TLDs as a function of depth (A) in absorbers, within a fixed solid angle centered about the beam axis. This expression is quantified for the measurements presented here.