X-ray ionization yields and energy spectra in liquid argon

TL;DR

This study provides systematic reference data on X-ray ionization yields, recombination coefficients, and energy spectra in liquid argon, crucial for optimizing cryogenic detectors in rare-event physics experiments.

Contribution

First systematic presentation of X-ray recombination coefficients and ionization yields in liquid argon across a broad energy range.

Findings

Recombination coefficients and ionization yields are now systematically characterized.

Energy spectra of pulsed X-rays in liquid argon are interpreted and validated.

Data supports improved calibration of liquid argon detectors.

Abstract

The main purpose of this work is to provide reference data on X-ray ionization yields and energy spectra in liquid Ar to the studies in the field of Cryogenic Avalanche Detectors (CRADs) for rare-event and other experiments, based on liquid Ar detectors. We present the results of two related researches. First, the X-ray recombination coefficients in the energy range of 10-1000 keV and ionization yields at different electric fields, between 0.6 and 2.3 kV/cm, are determined in liquid Ar based on the results of a dedicated experiment. Second, the energy spectra of pulsed X-rays in liquid Ar in the energy range of 15-40 keV, obtained in given experiments including that with the two-phase CRAD, are interpreted and compared to those calculated using a computer program, to correctly determine the absorbed X-ray energy. The X-ray recombination coefficients and ionization yields have for the first time been presented for liquid Ar in systematic way.