Accurate experimental determination of Gallium K- and L3-shell XRF fundamental parameters

TL;DR

This study accurately measured gallium's K- and L3-shell fluorescence yields using calibrated XRF at a synchrotron, providing uncertainties and validating against existing data, and derived photoionization cross sections.

Contribution

First-time determination of gallium's fluorescence yields with comprehensive uncertainty analysis and comparison with standard databases.

Findings

Fluorescence yields are consistent with existing data.

Uncertainty budgets improve reliability of measurements.

Photoionization cross sections were critically compared with standards.

Abstract

The fluorescence yield of the K- and L3-shell of gallium was determined using the radiometrically calibrated (reference-free) X-ray fluorescence instrumentation at the BESSY II synchrotron radiation facility. Simultaneous transmission and fluorescence signals from GaSe foils were obtained, resulting in K- and L3-shell fluorescence yield values consistent with existing database values(omega_Ga_K=0.515 +- 0.019, omega_Ga_L3=0.013 +- 0.001). For the first time, these standard combined uncertainties are obtained from a properly constructed Uncertainty Budget. These K-shell fluorescence yield values support Bambynek's semi-empirical compilation from 1972: these and other measurements yield a combined recommended value of omega_Ga_K=0.514 +- 0.010. Using the measured fluorescence yields together with production yields from reference Ga-implanted samples where the quantity of implanted Ga was determined at 1.3% traceable accuracy by Rutherford backscattering spectrometry, the K-shell and L3-subshell photoionization cross sections at selected incident photon energies were also determined and compared critically with the standard databases.