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Title: Electroluminescence pulse shape and electron diffusion in liquid argon measured in a dual-phase TPC

Abstract

We report the measurement of the longitudinal diffusion constant in liquid argon with the DarkSide-50 dual-phase time projection chamber. The measurement is performed at drift electric fields of 100 V/cm, 150 V/cm, and 200 V/cm using high statistics $$^{39}$$Ar decays from atmospheric argon. We derive an expression to describe the pulse shape of the electroluminescence signal (S2) in dual-phase TPCs. The derived S2 pulse shape is fit to events from the uppermost portion of the TPC in order to characterize the radial dependence of the signal. The results are provided as inputs to the measurement of the longitudinal diffusion constant DL, which we find to be (4.12 $$\pm$$ 0.04) cm$^2$/s for a selection of 140keV electron recoil events in 200V/cm drift field and 2.8kV/cm extraction field. To study the systematics of our measurement we examine datasets of varying event energy, field strength, and detector volume yielding a weighted average value for the diffusion constant of (4.09 $$\pm$$ 0.09) cm$^2$ /s. The measured longitudinal diffusion constant is observed to have an energy dependence, and within the studied energy range the result is systematically lower than other results in the literature.

Authors:
;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Org.:
DarkSide
OSTI Identifier:
1422495
Report Number(s):
arXiv:1802.01427; FERMILAB-PUB-18-043-E
1653194
DOE Contract Number:
AC02-07CH11359
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nucl.Instrum.Meth.A
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY

Citation Formats

Agnes, P., and et al. Electroluminescence pulse shape and electron diffusion in liquid argon measured in a dual-phase TPC. United States: N. p., 2018. Web.
Agnes, P., & et al. Electroluminescence pulse shape and electron diffusion in liquid argon measured in a dual-phase TPC. United States.
Agnes, P., and et al. Mon . "Electroluminescence pulse shape and electron diffusion in liquid argon measured in a dual-phase TPC". United States. doi:. https://www.osti.gov/servlets/purl/1422495.
@article{osti_1422495,
title = {Electroluminescence pulse shape and electron diffusion in liquid argon measured in a dual-phase TPC},
author = {Agnes, P. and et al.},
abstractNote = {We report the measurement of the longitudinal diffusion constant in liquid argon with the DarkSide-50 dual-phase time projection chamber. The measurement is performed at drift electric fields of 100 V/cm, 150 V/cm, and 200 V/cm using high statistics $^{39}$Ar decays from atmospheric argon. We derive an expression to describe the pulse shape of the electroluminescence signal (S2) in dual-phase TPCs. The derived S2 pulse shape is fit to events from the uppermost portion of the TPC in order to characterize the radial dependence of the signal. The results are provided as inputs to the measurement of the longitudinal diffusion constant DL, which we find to be (4.12 $\pm$ 0.04) cm$^2$/s for a selection of 140keV electron recoil events in 200V/cm drift field and 2.8kV/cm extraction field. To study the systematics of our measurement we examine datasets of varying event energy, field strength, and detector volume yielding a weighted average value for the diffusion constant of (4.09 $\pm$ 0.09) cm$^2$ /s. The measured longitudinal diffusion constant is observed to have an energy dependence, and within the studied energy range the result is systematically lower than other results in the literature.},
doi = {},
journal = {Nucl.Instrum.Meth.A},
number = ,
volume = ,
place = {United States},
year = {Mon Feb 05 00:00:00 EST 2018},
month = {Mon Feb 05 00:00:00 EST 2018}
}