An Improved Evaluation of the Neutron Background in the PandaX-II Experiment

Abstract

In dark matter direct detection experiments, neutron is a serious source of background, which can mimic the dark matter-nucleus scattering signals. In this paper, we present an improved evaluation of the neutron background in the PandaX-II dark matter experiment by a novel approach. Instead of fully relying on the Monte Carlo simulation, the overall neutron background is determined from the neutron-induced high energy signals in the data. In addition, the probability of producing a dark-matter-like background per neutron is evaluated with a complete Monte Carlo generator, where the correlated emission of neutron(s) and $\gamma$(s) in the ($\alpha$, n) reactions and spontaneous fissions is taken into consideration. With this method, the neutron backgrounds in the Run 9 (26-ton-day) and Run 10 (28-ton-day) data sets of PandaX-II are estimated to be 0.66$\pm$0.24 and 0.47$\pm$0.25 events, respectively.

9 pages, 9 figures, 7 tables; version2 accepted by Sci. China Phys. Mech. Astron

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• Dark Matter Results From 54-Ton-Day Exposure of PandaX-II Experiment
• Dark Matter Results from First 98.7-day Data of PandaX-II Experiment
• Current status of direct dark matter detection experiments
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• PandaX-xT: a Multi-ten-tonne Liquid Xenon Observatory at the China Jinping Underground Laboratory
• Diurnal Effect of Sub-GeV Dark Matter Boosted by Cosmic Rays
• Determination of responses of liquid xenon to low energy electron and nuclear recoils using the PandaX-II detector
• Constraining self-interacting dark matter with the full dataset of PandaX-II
• Dark Matter Capture by Atomic Nuclei
• Horizontal Position Reconstruction in PandaX-II
• Study of background from accidental coincidence signals in the PandaX-II experiment
• Neutron-induced nuclear recoil background in the PandaX-4T experiment
• BambooMC -- A Geant4-based simulation program for the PandaX experiments