Investigation of the cryogenic scintillation of pure and doped sodium-iodine

Abstract

We have studied the scintillation of pure and doped sodium iodide crystals handled in low humidity conditions under external $\alpha$ and $\gamma$ excitation from room temperature down to 4K. The light yield of pure sodium iodide was seen to increase at low temperatures by a factor 30 compared to room temperature, up to a maximum of 40 photons/keV under $\gamma$ excitation at 60K, stabilizing to 30 photons/keV at lower temperatures. Thallium doped sodium iodide fluctuates by 20% around the room temperature value, stabilizing at 40 photons/keV at low temperature. $\alpha /\gamma$ quenching factor stabilizes at roughly 0.7 for both materials beneath 50K. Time constants of both materials slow greatly at low temperature, reaching tens of microseconds. Cryogenic applications of these materials are complexified by their mechanical fragility and hygroscopicity.

16 pages, 8 figures

References in corpus (6)

• Performance of scintillation materials at cryogenic temperatures
• First results on dark matter annual modulation from ANAIS-112 experiment
• Strong constraints from COSINE-100 on the DAMA dark matter results using the same sodium iodide target
• Low temperature light yield measurements in NaI and NaI(Tl)
• Sensitivity of alkali halide scintillating calorimeters with particle identification to investigate the DAMA dark matter detection claim
• SABRE and the Stawell Underground Physics Laboratory: Dark Matter Research at the Australian National University