Modeling ionization and recombination from low energy nuclear recoils in liquid argon

Abstract

Coherent elastic neutrino-nucleus scattering (CENNS) is an as-yet undetected, flavor-independent neutrino interaction predicted by the Standard Model. Detection of CENNS could offer benefits for detection of supernova and solar neutrinos in astrophysics, or for detection of antineutrinos for nuclear reactor monitoring and nuclear nonproliferation. One challenge with detecting CENNS is the low energy deposition associated with a typical CENNS nuclear recoil. In addition, nuclear recoils result in lower ionization yields than those produced by electron recoils of the same energy. While a measurement of the nuclear recoil ionization yield in liquid argon in the keV energy range has been recently reported, a corresponding model for low-energy ionization yield in liquid argon does not exist. For this reason, a Monte Carlo simulation has been developed to predict the ionization yield at sub-10 keV energies. The model consists of two distinct components: (1) simulation of the atomic collision cascade with production of ionization, and (2) the thermalization and drift of ionization electrons in an applied electric field including local recombination. As an application of our results we report updated estimates of detectable ionization in liquid argon from CENNS at a nuclear reactor.

Antineutrino Detectors Remain Impractical for Nuclear Explosion Monitoring

“…The use of gadolinium decreases the neutron capture time and allows for particle identification to be performed based on the observation of the positron and neutron signals in coincidence (Kim, 2016). One may explore the option of using alternative detection mechanisms (such as neutrino-electron elastic scattering or coherent elastic neutrino-nucleus scattering) to detect the antineutrinos (Hagmann & Bernstein, 2004;Scholberg, 2015), but these other detection mechanisms do not offer the signal detection (Sangiorgio et al, 2013) or discrimination (antineutrino events and background) capabilities required for nuclear explosion monitoring (Foxe et al, 2015).…”

Electron swarm and streamer transport across the gas–liquid interface: a comparative fluid model study

“…It should be noted that this study assumes that ion transport is neglected over the timescales studied [45,46], and that, for simplicity, singly ionized molecular argon ions are only considered in this study. Furthermore, electron-ion recombination and the formation of excited states are neglected in this study as it was found that at the applied reduced fields used in this study, for the electron and ion densities in liquid argon, the resulting recombination rates [50][51][52][53][54] were significant orders of magnitude less than the other collisional processes considered in this work.…”

Electron recombination in low-energy nuclear recoils tracks in liquid argon

“…It was used to explain the LET dependence of the recombination factor measured in high-energy stopping muon and stopping proton tracks [25], and was used by the ArgoNeuT collaboration to interpret their results of the angular dependence, with respect to the drift field, of the recombination probability [26]. Our model was also used by Foxe et al [27] to describe the recombination stage in their calculations of the ionization yield from electron recoils in LAr. Very recently, a study of nuclear recoils in LAr by those authors, independent of our work, has also appeared [28], which includes a limited description of the recombination process.…”

“…Our model was also used by Foxe et al [27] to describe the recombination stage in their calculations of the ionization yield from electron recoils in LAr. Very recently, a study of nuclear recoils in LAr by those authors, independent of our work, has also appeared [28], which includes a limited description of the recombination process.…”