Neutral Bremsstrahlung Emission in Xenon Unveiled

We present evidence of non-excimer-based secondary scintillation in gaseous xenon, obtained using both the NEXT-White time projection chamber (TPC) and a dedicated setup. Detailed comparison with first-principle calculations allows us to assign this mechanism neutral bremsstrahlung (NBrS), process that is postulated exist xenon has been largely overlooked. For photon emission below 1000 nm, NBrS yield increases from about 10−2 photon/e− cm−1 bar−1 at pressure-reduced electric field values 50 V above 3×10−1 500 bar−1. Above 1.5 kV bar−1, are typically employed for electroluminescence, it estimated an intensity around 1 which 2 orders magnitude lower than conventional, excimer-based electroluminescence. Despite being fainter its excimeric counterpart, our reveal causes luminous backgrounds can interfere, either gas or liquid phase, ability distinguish and/or precisely measure low primary-scintillation signals (S1). In particular, we show be case “buffer” region, where keeping electroluminescence threshold does not suffice extinguish scintillation. The leakage region should mitigated avoid intolerable levels emission. Furthermore, new source light opens up viable path toward obtaining S2 discrimination purposes future single-phase TPCs neutrino dark matter physics, yields 20–50 photons/e− cm−1.10 MoreReceived 22 November 2020Revised 14 January 2022Accepted 24 2022Corrected 13 May 2022DOI:https://doi.org/10.1103/PhysRevX.12.021005Published by American Physical Society under terms Creative Commons Attribution 4.0 International license. Further distribution work must maintain attribution author(s) published article’s title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasCosmic ray & astroparticle detectorsNeutrinoless double beta decayParticle astrophysicsParticle matterParticle interactionsPhysical SystemsNeutrinosPhotonsWeakly interacting massive particlesTechniquesDark detectorsGaseous detectorsNeutrino detectorsParticle detectorsScintillatorsTime-projection chambersGravitation, Cosmology AstrophysicsParticles Fields