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Abstract A double-phase argon Time Projection Chamber (TPC), with an active mass of 185 g, has been designed and constructed for the Recoil Directionality (ReD) experiment. The aim of the ReD project is to investigate the directional sensitivity of argon-based TPCs via columnar recombination to nuclear recoils in the energy range of interest (20– $$200\,\hbox {keV}_{nr}$$ 200 keV nr ) for direct dark matter searches. The key novel feature of the ReD TPC is a readout system based on cryogenic Silicon Photomultipliers (SiPMs), which are employed and operated continuously for the first time in an argon TPC. Over the course of 6 months, the ReD TPC was commissioned and characterised under various operating conditions using $$\gamma $$ γ -ray and neutron sources, demonstrating remarkable stability of the optical sensors and reproducibility of the results. The scintillation gain and ionisation amplification of the TPC were measured to be $$g_1 = (0.194 \pm 0.013)$$ g 1 = ( 0.194 ± 0.013 ) photoelectrons/photon and $$g_2 = (20.0 \pm 0.9)$$ g 2 = ( 20.0 ± 0.9 ) photoelectrons/electron, respectively. The ratio of the ionisation to scintillation signals (S2/S1), instrumental for the positive identification of a candidate directional signal induced by WIMPs, has been investigated for both nuclear and electron recoils. At a drift field of 183 V/cm, an S2/S1 dispersion of 12% was measured for nuclear recoils of approximately 60– $$90\,\hbox {keV}_{nr}$$ 90 keV nr , as compared to 18% for electron recoils depositing 60 keV of energy. The detector performance reported here meets the requirements needed to achieve the principal scientific goals of the ReD experiment in the search for a directional effect due to columnar recombination. A phenomenological parameterisation of the recombination probability in LAr is presented and employed for modeling the dependence of scintillation quenching and charge yield on the drift field for electron recoils between 50–500 keV and fields up to 1000 V/cm.
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Low energy electronic recoils and single electron detection with a liquid Xenon proportional scintillation counter
Abstract Liquid xenon (LXe) is a well-studied detector medium to search for rare events in dark matter and neutrino physics. Two-phase xenon time projection chambers (TPCs) can detect electronic and nuclear recoils with energy down to kilo-electron volts (keV). In this paper, we characterize the response of a single-phase liquid xenon proportional scintillation counter (LXePSC), which produces electroluminescence directly in the liquid, to detect electronic recoils at low energies. Our design uses a thin (10–25 μm diameter), central anode wire in a cylindrical LXe target where ionization electrons, created from radiation particles, drift radially towards the anode, and electroluminescence is produced. Both the primary scintillation (S1) and electroluminescence (S2) are detected by photomultiplier tubes (PMTs) surrounding the LXe target. Up to 17 photons are produced per electron, obtained with a 10 μm diameter anode wire, allowing for the highly efficient detection of electronic recoils from beta decays of a tritium source down to ∼ 1 keV. Single electrons, from photoemission of the cathode wires, are observed at a gain of 1.8 photoelectrons (PE) per electron. The delayed signals following the S2 signals are dominated by single-photon-like hits, without evidence for electron signals observed in the two-phase xenon TPCs. We discuss the potential application of such a LXePSC for reactor neutrino detection via Coherent Elastic Neutrino Nucleus Scattering (CEνNS).
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- Award ID(s):
- 2137911
- PAR ID:
- 10471351
- Publisher / Repository:
- IOP Publishing Ltd and Sissa Medialab
- Date Published:
- Journal Name:
- Journal of Instrumentation
- Volume:
- 18
- Issue:
- 07
- ISSN:
- 1748-0221
- Page Range / eLocation ID:
- P07027
- Subject(s) / Keyword(s):
- Noble liquid detectors (scintillation, ionization, double-phase) Charge transport and multiplication in liquid media Charge transport, multiplication and electroluminescence in rare gases and liquids Neutron detectors (cold, thermal, fast neutrons)
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1088/1748-0221/18/07/P07027
