Measurement of Longitudinal Electron Diffusion in Liquid Argon

TL;DR

This paper presents precise measurements of longitudinal electron diffusion coefficients in liquid argon across a range of electric fields, providing data that surpasses previous measurements and theoretical predictions.

Contribution

It offers the most accurate measurements of electron diffusion in liquid argon from 350 to 2000 V/cm, using a novel experimental setup with a gold photocathode.

Findings

Results are consistent with previous data between 100-350 V/cm.

Measured diffusion coefficients are systematically higher than theoretical predictions.

Provides data for electric fields between 350-2000 V/cm.

Abstract

We report the measurement of longitudinal electron diffusion coefficients in liquid argon for electric fields between 100 and 2000 V/cm with a gold photocathode as a bright electron source. The measurement principle, apparatus, and data analysis are described. Our results, which are consistent with previous measurements in the region between 100 to 350 V/cm [1] , are systematically higher than the prediction of Atrazhev-Timoshkin[2], and represent the world's best measurement in the region between 350 to 2000 V/cm. The quantum efficiency of the gold photocathode, the drift velocity and longitudinal diffusion coefficients in gas argon are also presented.