Effect of an electric field on electron attachment to sulfur hexafluoride, nitrous oxide, and molecular oxygen in liquid argon and xenon

Abstract

The rate constant for electron attachment to SFg, N20, and 02 in liquid argon and xenon was studied as a function of an external electric field up to 5 V cm-1. While Me-" + SF6) and k(e~+ 02) decreased with increasing field strength, Me-+ N20) exhibited a nearly 100 fold increase. The field effect on the rate constant in the liquefied rare gases is related to the increase of the mean electron energy by the external field. By means of the Cohen-Lekner theory electron energy distribution functions were obtained and a rough estimate of the energy dependence of the attachment cross section could be deduced.

Liquid noble gas detectors for low energy particle physics

“…Its sensitivity is limited by a high partial pressure of the bulk gas; however, using a cold trap between the gas inlet and the mass spectrometer can improve the sensitivity to ppb levels [191]. Oxygen and water are the most common electronegative contaminants, but it is not unusual to measure electron lifetimes which decrease with electric field, just opposite to what would be expected for these species [192]; N 2 O is often blamed for this behavior but, to our knowledge, the evidence for its presence in most systems is not conclusive. The presence of nitrogen has been detected in some setups where a significant reduction of secondary light in the gas phase was observed; in doublephase systems, a significant nitrogen concentration can build up in the thin gas layer above a large LXe target to quench the secondary scintillation completely.…”

Xenon purity analysis for EXO-200 via mass spectrometry

“…For example, the O 2 concentration should be less than ∼1 ppb in order to collect ionization over the 20 cm drift length of the detector [8]. Other eletronegative impurity species may have larger or smaller attachment coefficients.…”

Double Beta Decay in Xenon-136. Measuring the Neutrino-Emitting Mode and Searching for Majoron-Emitting Modes

“…. [53], showing the electron attachment constant as a function of electric field strength. On the right is the measured electron lifetime, which is inversely proportional to the attachment constant, for a number of electric field strengths.…”