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We consider the potential for a 10 kg undoped cryogenic CsI detector operating at the Spallation Neutron Source to measure coherent elastic neutrino-nucleus scattering and its sensitivity to discover new physics beyond the standard model (BSM). Through a combination of increased event rate, lower threshold, and good timing resolution, such a detector would significantly improve on past measurements. We considered tests of several BSM scenarios such as neutrino nonstandard interactions and accelerator-produced dark matter. This detector’s performance was also studied for relevant questions in nuclear physics and neutrino astronomy, namely the weak charge distribution of Cs and I nuclei and detection of neutrinos from a core-collapse supernova.

Published by the American Physical Society2024 

Abstract We present results of several measurements of CsI[Na] scintillation response to 3–60 keV energy nuclear recoils performed by the COHERENT collaboration using tagged neutron elastic scattering experiments and an endpoint technique. Earlier results, used to estimate the coherent elastic neutrino-nucleus scattering (CEvNS) event rate for the first observation of this process achieved by COHERENT at the Spallation Neutron Source (SNS), have been reassessed. We discuss corrections for the identified systematic effects and update the respective uncertainty values. The impact of updated results on future precision tests of CEvNS is estimated. We scrutinize potential systematic effects that could affect each measurement. In particular we confirm the response of the H11934-200 Hamamatsu photomultiplier tube (PMT) used for the measurements presented in this study to be linear in the relevant signal scale region. 

Abstract We present the analysis and results of the first datasetcollected with the MARS neutron detectordeployed at the Oak Ridge NationalLaboratory Spallation Neutron Source (SNS) for the purpose ofmonitoring and characterizing the beam-related neutron (BRN) backgroundfor the COHERENT collaboration. MARS was positionednext to the COH-CsI coherent elastic neutrino-nucleus scattering detectorin the SNS basement corridor. This is the basement location ofclosest proximity to the SNS target and thus, of highest neutrino flux,but it is also well shielded from the BRN flux by infill concreteand gravel. These data show the detector registered roughly one BRN per day.Using MARS' measured detection efficiency, the incomingBRN flux is estimated to be 1.20 ± 0.56 neutrons/m^2/MWhfor neutron energies above ∼3.5 MeV and up to a few tens of MeV.We compare our results with previous BRN measurements in the SNS basement corridorreported by other neutron detectors.