Speaker
Description
The KIMS experiment previously used CsI(Tl) crystals for dark matter searches, employing pulse shape discrimination (PSD) to distinguish nuclear recoil signals from electron recoil backgrounds. However, the sensitivity was limited by a relatively low light yield of approximately 5 photoelectrons (PE) per keV, mainly due to the low quantum efficiency of conventional PMTs in the green emission range characteristic of CsI(Tl). Recent advances by Hamamatsu Photonics have led to the development of high quantum efficiency PMTs with green-extended photocathodes. By coupling CsI(Tl) crystals with two Hamamatsu R11934 1-inch PMTs, we have achieved a significantly improved light yield of up to 11 PE/keV. Since PSD performance strongly depends on photon statistics, this enhancement is expected to substantially improve background discrimination power. In this presentation, we report on the light yield and PSD performance of a CsI(Tl) detector coupled with two high quantum efficiency PMTs. We also present results from PSD measurements using a neutron generator to compare nuclear and electron recoil responses. Additionally, we discuss the design considerations of high-light-yield CsI(Tl) detectors optimized for future dark matter searches.
| Collaboration you are representing | COSINE |
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