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.

References in corpus (12)

• First Results from the DarkSide-50 Dark Matter Experiment at Laboratori Nazionali del Gran Sasso
• Liquid noble gas detectors for low energy particle physics
• Results from the first use of low radioactivity argon in a dark matter search
• Measurement of the specific activity of Ar-39 in natural argon
• Measurement of Longitudinal Electron Diffusion in Liquid Argon
• The veto system of the DarkSide-50 experiment
• Simulation of argon response and light detection in the DarkSide-50 dual phase TPC
• Luminescence quenching of the triplet excimer state by air traces in gaseous argon
• The Electronics, Trigger and Data Acquisition System for the Liquid Argon Time Projection Chamber of the DarkSide-50 Search for Dark Matter
• Effect of Low Electric Fields on Alpha Scintillation Light Yield in Liquid Argon
• CALIS - a CALibration Insertion System for the DarkSide-50 dark matter search experiment
• The Electronics and Data Acquisition System for the DarkSide-50 Veto Detectors

Cited by in corpus (16)

• Low-Mass Dark Matter Search with the DarkSide-50 Experiment
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• Revealing neutral bremsstrahlung in two-phase argon electroluminescence
• Sensitivity projections for a dual-phase argon TPC optimized for light dark matter searches through the ionization channel
• Sensitivity of future liquid argon dark matter search experiments to core-collapse supernova neutrinos
• Measurements of electron transport in liquid and gas Xenon using a laser-driven photocathode
• Electron transport and electric field simulations in two-phase detectors with THGEM electrodes
• Neutral bremsstrahlung in two-phase argon electroluminescence: further studies and possible applications
• Puzzling time properties of proportional electroluminescence in two-phase argon detectors for dark matter searches
• Observation of unusual slow components in electroluminescence signal of two-phase argon detector
• Search for dark matter annual modulation with DarkSide-50
• Development of a Monte Carlo tool for simulating electron transport in noble liquids
• Fermionic sub-GeV Dark Matter from evaporating Primordial Black Holes at DarkSide-50
• A Comprehensive Monte Carlo Simulation Tool on Electron Transport in Noble Gases and Liquids
• Measuring the Low-Energy Weak Mixing Angle with Supernova Neutrinos
• Performance of the ReD TPC, a novel double-phase LAr detector with Silicon Photomultiplier Readout