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Snowmass White Paper Coordination Workshop - Shared screen with speaker view
Thomas Tsang
01:01:39
On the radioacitivity of Kr, years ago we (BNL) made dark count rate measurement of VUV sensitive SiPMs in purified LAr, LKr, and LXe. A significantly higher DCR was observed in LKr than LAr or LXe, about a factor of 100. So LKr do glow (at 155 nm) more than LAr (128 nm). We speculated that it was due to the natural Kr-85 radioactivity (687 keV) remained in the Earth’s atmosphere after dissolving of nuclear fuel for military and civilian purposes in the past decades.
Kate Scholberg
01:03:05
thanks, Thomas
Kate Scholberg
01:05:32
I thought the Kr-85 rate in natural krypton was very much higher than Ar-39 in natural Ar, but seems that is not so. Low level glow is indeed probably not a major problem for TeV scale events
Milind Diwan
01:06:07
We should certainly make the measurement in Krypton again.
Kate Scholberg
01:06:53
I guess both Kr-81 and Kr-85 are present
Milind Diwan
01:06:54
I think Krypton 81 contributes also.
Milind Diwan
01:07:56
We would have to study how to trigger. There is no reason to trigger below ~few hundred MeV. Even this is debatable since the low trigger is driven by dark matter scattering.