We report the performance of an active veto system using a liquid scintillator with NaI(Tl) crystals for use in a dark matter search experiment. When a NaI(Tl) crystal is immersed in the prototype detector, the detector tags 48% of the internal K-40 background in the 0-10 keV energy region. We also determined the tagging efficiency for events at 6-20 keV as 26.5 +/- 1.7% of the total events, which corresponds to 0.76 +/- 0.04 events/keV/kg/day. According to a simulation, approximately 60% of the background events from U, Th, and K radioisotopes in photomultiplier tubes are tagged at energies of 0-10 keV. Full shielding with a 40-cm-thick liquid scintillator can increase the tagging efficiency for both the internal K-40 and external background to approximately 80%.
@article{arxiv.1701.04514,
title = {Performance of a prototype active veto system using liquid scintillator for a dark matter search experiment},
author = {J. S. Park and P. Adhikari and G. Adhikari and S. Y. Oh and N. Y. Kim and Y. D. Kim and C. Ha and K. S. Park and H. S. Lee and E. J. Jeon},
journal= {arXiv preprint arXiv:1701.04514},
year = {2017}
}
Comments
Submitted to Nuclear Instruments and Methods in Physics Research Section A