Characterisation of an ultra low-background point contact HPGe well-detector for an underground laboratory

Abstract

Since a few years there are well-type HPGe-detectors with a small, point-like, anode contacts available commercially. This paper describes the characterisation of the first ultra low-background, so-called, SAGe™ well detector with regards to resolution and background performance. Inside a passive lead/copper shield in the underground laboratory HADES a background count rate of 690 ± 6d (268 ± 3d per kg Ge) was recorded 19 months after taking it underground.

Enriched Regions of 228Ra Along the U.S. GEOTRACES Pacific Meridional Transect (GP15)

“…The Mn-cartridge ash was transferred to 15 mm diameter polystyrene vials and sealed with epoxy (to prevent 222 Rn loss). Samples were counted for a minimum of one week and a maximum of one month in high purity, well-type germanium detectors at the underground research facility "HADES" in Belgium (Hult et al, 2019(Hult et al, , 2020 to quantify 226 Ra via the 214 Pb photopeak at 352 keV and 228 Ra via the 228 Ac photopeaks at 338, 911, and 969 keV or by 228 Th ingrowth ( 212 Pb photopeak at 238 keV) as described below. The detectors were calibrated using ash prepared from Mn-cartridges soaked in a standard solution containing 226 Ra and 232 Th (with daughters in equilibrium).…”

Underground radioactivity measurements of meteorites: Development of methods suitable to determine precise terrestrial age of recent falls

“…The measurements were performed by non-destructive ultra lowlevel gamma-ray spectrometry at the underground facility HADES (225 m below ground) located at the premises of the Belgian Nuclear Research Centre (Hult et al, 2020). A planar p-type BEGe-detector from Mirion (Canberra) with a Ge-crystal diameter of 80 mm and 30 mm height (relative efficiency of 50%) was used (Hult et al, 2013).…”

Characterisation of the natural gamma-ray background in the underground Callio Lab facility

“…As a first step, the background radiation level in Callio Lab was examined using the NitroSPEC, MultiSPEC-6000 and BDEG-51-51-CeBr 3 portable spectrometers. Both HPGe [7,[10][11][12][13][14][15] and scintillation [17,19] detectors have been used to characterise the background levels in underground facilities. We used CZT detectors in this study for two reasons: (1) increased efficiency of registration of clustered CZT detectors; and (2) improved resolution.…”