Pressure effects on the X-ray intrinsic position resolution in noble gases and mixtures

Azevedo C. D. R., Gonzalez-Diaz D., Correia P. M. M., Biagi S., Silva A. L. M., Carramate L. F. N. D., ...More

JOURNAL OF INSTRUMENTATION, vol.11, 2016 (SCI-Expanded) identifier identifier


A study of the effect of gas pressure in the position resolution of an interacting X or gamma-ray photon in a gas medium is performed. The intrinsic position resolution for pure noble gases (Argon and Xenon) and their mixtures with CO2 and CH4 was calculated for several gas pressures (1-10 bar) and for photon energies between 1 and 60 keV, being possible to establish a linear relation between the intrinsic position resolution and the inverse of the gas pressure in the indicated energy range, as intuitively expected. We show how, at high pressures and low photoelectron energies, this intrinsic 1/P scaling is modified due to the diffusion of the primary ionization in the direction perpendicular to the electric field.