Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8165915 | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | 2018 | 12 Pages |
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 39Ar 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 ± 0.09) cm2/s for a selection of 140 keV electron recoil events in 200 V/cm drift field and 2.8 kV/cm extraction field. To study the systematics of our measurement we examine data sets of varying event energy, field strength, and detector volume yielding a weighted average value for the diffusion constant of (4.09 ± 0.12) cm2/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.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Instrumentation
Authors
P. Agnes, I.F. M. Albuquerque, T. Alexander, A.K. Alton, D.M. Asner, M.P. Ave, H.O. Back, B. Baldin, G. Batignani, K. Biery, V. Bocci, G. Bonfini, W. Bonivento, M. Bossa, B. Bottino, F. Budano, S. Bussino, M. Cadeddu, G. Zuzel,