New paper, DEAP-3600, and COHERENT CsI[Na]¶
Since my last news post, the MARLEY v1.2.0 implementation paper was published by Computer Physics Communications. The recommended citations to use for MARLEY have been updated accordingly.
New MARLEY-based simulations of 8B solar neutrino events in the DEAP-3600 liquid argon dark matter experiment were reported in a recent poster presented by Andrew Erlandson at LIDINE 2021. By combining MARLEY with RAT-PAC to simulate the detector response and apply a realistic event selection, the DEAP-3600 collaboration obtains an estimated rate of 7.34 ± 0.66 charged-current solar νe events in a 7.20 tonne-year exposure assuming 100% acceptance. If follow-up studies of backgrounds and acceptance conclude favorably, there could be an exciting opportunity for DEAP-3600 to achieve a first detection of these neutrinos in liquid argon.
The COHERENT collaboration also reported an interesting MARLEY calculation in a recent preprint describing a measurement of coherent elastic neutrino-nucleus scattering (CEvNS) using a CsI[Na] detector. To mitigate γ-ray backgrounds, the CsI[Na] crystal is shielded with low-activity lead. Neutrino reactions occurring within the lead can eject neutrons, potentially leading to spurious CEvNS-like signals in the detector. While a data-driven estimate of the rate of these neutrino-induced neutrons (NINs) was used in the CEvNS cross-section analysis, the NIN energy spectrum was approximated using the results of a MARLEY simulation. No official reaction input files have been released yet for 208Pb (or any of the other Pb isotopes), but user-defined ones may be provided (see appendix B of the MARLEY v1.2.0 paper), as was done in this analysis.
It continues to be fun to learn about new and exciting applications of MARLEY. Please keep them coming!