Bremsstrahlung spectra produced from kilovolt electrons incident on thick targets of Ti, W and Pt

Abstract

Measurements of x-ray emission spectra generated by 10–20 keV electrons impinging normally on bulk targets of pure elements Ti (Z = 22), W (Z = 74) and Pt (Z = 78) have been performed using an experimental setup developed for studying electron–atom/molecule collisions in our laboratory. Values extracted from the experimental data for bremsstrahlung yield, integrated yield and mean energy of the bremsstrahlung radiation beam for the above collision systems have been compared with the simulation results obtained from the general purpose Monte Carlo simulation code PENELOPE. The comparisons are found to show a satisfactory agreement between them within their statistical uncertainties. Some apparent mismatches are observed for which possible causes and their origins are discussed.

Bremsstrahlung spectra produced by kilovolt electron impact on thick targets

“…In contrast with the recent results of Agnihotri et al [22], our results are consistent with the work of Salvat, Llovet and Acosta et al [17][18][19][20] and [16], and provide further evidence for the reliability of the adopted interaction crosssections and the accuracy of the simulation algorithms implemented in PENELOPE for the bremsstrahlung emission, at least for the reliability of their combined choices. As for discrepancies between the experimental spectra and PENELOPE simulations in [22], the most possible reason could be incomplete collection of the incident electron charge. The charge used to normalize the experimental X-ray spectra were collected only from the thick targets, and backscattered electrons were not collected.…”

“…The electron beam current was collected by a deep Faraday cup and then was fed into an ORTEC digital current integrator, which has an accuracy of less than 1% for the charge measurements. With this method, the difficulty of incomplete charge collection which may account for the large discrepancy observed in [22] can be overcome. Thick targets with polished surfaces were mounted on the target holder.…”

“…[16,21] have also presented measured results for bremsstrahlung radiated at 90°and 135°for 50 and 53 keV electrons impacting on solid gold targets of different thicknesses and agreement with PENELOPE was good. However, in a recent study [22] there were apparent discrepancies between the simulation results from PENELOPE and experimental measurements of X-ray emission spectra generated by 10-20 keV electrons impinging normally on bulk targets of W, Ti, Pt and detected at 135°to the incident beam direction. Therefore, we consider that more accurate measurements are needed for a variety of energies and targets to prove the reliability of the adopted interaction cross-sections and the accuracy of the algorithms implemented in PENELOPE for bremsstrahlung.…”

Measurement of the bremsstrahlung spectra generated from thick targets with Z=2–78 under the impact of 10 keV electrons

“…For calculating the double differential cross-sections from the results of MonteCarlo simulation, we have divided the bremsstrahlung photon yields [14] given by the expression…”

“…Semaan and Quarles [13] proposed a model for calculating the thick target bremsstrahlung crosssections for incident electrons having energies between 10 and 25 keV, corrected for electron energy loss, electron backscattering, photon attenuation in the target and efficiency of X-ray detector. Recently, Agnihotri et al [14] published their work on thick target bremsstrahlung emitted from 10-28 keV electrons incident on Ti, W and Pt and reported results for bremsstrahlung yield, integrated yield and mean energy of the bremsstrahlung beam. A good agreement was obtained between their experiment and MC calculations using PENELOPE code [15].…”