Study of visible-light emission in pure and methane-doped liquid argon

Bondar, A.; Borisova, E.; Frolov, E.; Nosov, V. V.; Oleynikov, V.; Sokolov, A.

doi:10.1088/1748-0221/17/09/p09009

Cited by 4 publications

(2 citation statements)

References 52 publications

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“…In addition to fast and slow components, the latter having a time constant of about 5 µs, one can also see the second slow component, further referred to as "long" component, with a tenfold larger time constant, of about 50 µs. The weak primary scintillation (S1) signal was also observed at about 30 µs before the S2 signal (for its details see the recent study on visible-light scintillations in liquid Ar [60]). For the correct analysis of the S2 pulse shape it is necessary to separate the events induced by radioactive sources from background (mostly caused by cosmic rays and radioactivity of materials inside the detector).…”

Section: Measurements Of S2 Amplitudes and Pulse Shapes In Two-phase ...mentioning

confidence: 91%

Puzzling time properties of proportional electroluminescence in two-phase argon detectors for dark matter searches

Frolov¹,

Borisova²,

Nosov³

et al. 2022

Eur. Phys. J. C

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Proportional electroluminescence (EL) in noble gases is a physical process routinely used in two-phase (liquid–gas) detectors for low-energy astroparticle-physics experiments. In this work, the time properties of visible-light EL in two-phase argon detectors have been systematically studied for the first time. In particular, two unusual slow components in the EL signal, with their contributions and time constants increasing with electric field, were observed. This puzzling property is not expected in any of the known mechanisms of photon and electron emission in two-phase media. Time constants of these components is about 4–5 $$\upmu $$ μ s and 50 $$\upmu $$ μ s. In addition, a specific threshold behavior of the slow components was revealed: they emerged at a threshold in reduced electric field of 4.8 ± 0.2 Td regardless of the gas phase density, which is about 1 Td above the onset of standard (excimer) EL. There is a conspicuous similarity between this threshold and reduced field threshold of EL in NIR occurring via higher atomic excited states Ar$$^{*}(3p^{5}4p)$$ ∗ ( 3 p 5 4 p ) . An unexpected temperature dependence of slow components was also observed: their contribution decreased with temperature, practically disappearing at room temperature. We show that the puzzling properties of slow components can be explained in the framework of hypothesis that these are produced in the charge signal itself due to trapping of drifting electrons on metastable negative argon ions.

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Section: Measurements Of S2 Amplitudes and Pulse Shapes In Two-phase ...mentioning

confidence: 91%

Puzzling time properties of proportional electroluminescence in two-phase argon detectors for dark matter searches

Frolov¹,

Borisova²,

Nosov³

et al. 2022

Eur. Phys. J. C

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“…Methane (CH 4 ) can be doped into liquid argon at fractions of up to 50% by volume (44% molar fraction) [22] without losing solubility. The high solubility of methane has been confirmed for a LAr system operated under typical conditions, such as a saturated vapor pressure of 1.00 atm [23,24]. Therefore, it is feasible for LEGEND-1000 to heavily dope the atmLAr outside of the reentrant tubes, the so-called outer LAr volume.…”

Section: Jinst 19 P05056mentioning

confidence: 93%

Examining LEGEND-1000 cosmogenic neutron backgrounds in Geant4 and MCNP

Barton,

Xu,

Massarczyk

et al. 2024

J. Inst.

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For next-generation neutrinoless double beta decay experiments, extremely low backgrounds are necessary. An understanding of in-situ cosmogenic backgrounds is critical to the design effort. In-situ cosmogenic backgrounds impose a depth requirement and especially impact the choice of host laboratory. Often, simulations are used to understand background effects, and these simulations can have large uncertainties. One way to characterize the systematic uncertainties is to compare unalike simulation programs. In this paper, a suite of neutron simulations with identical geometries and starting parameters have been performed with Geant4 and MCNP, using geometries relevant to the LEGEND-1000 experiment. This study is an important step in gauging the uncertainties of simulations-based estimates. To reduce project risks associated with simulation uncertainties, a novel alternative shield of methane-doped liquid argon is considered in this paper for LEGEND-1000, which could achieve large background reduction without requiring significant modification to the baseline design.

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