HALO-1kT prototype He-3 counters: background studies
Date
2023-02-09
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Abstract
The last supernova near our galaxy was in 1987. HALO-1kT will be a low background galactic
Supernova detector. HALO- 1kT needs to have low backgrounds to detect a supernova on the far
side of the galaxy. A big source of backgrounds is the planned 4.3 km of helium-3 proportional
counters. My research tested the prototype proportional counters to ensure their backgrounds are
low enough to avoid regular false positives. The first way of testing them was to take the 4 counters
underground at SNOLAB to collect 3-4 months of data as well as a 2-day calibration run to see
what the base background rate is. Two of the counters were then attached to electrostatic counters
and counted to determine the background of the wall material. Those results showed emanation
rates of 0.137 Hz to 0.811 Hz in the wall material. While that is clean, it is not clean enough to
meet HALO-1kT background goals.