Background studies in the 148 m deep Reiche Zeche mine in Freiberg and in the 45 m deep Felsenkeller in Dresden


Background studies in the 148 m deep Reiche Zeche mine in Freiberg and in the 45 m deep Felsenkeller in Dresden

Szücs, T.; Agramunt, J.; Bemmerer, D.; Degering, D.; Dillmann, I.; Fraile, L. M.; Grieger, M.; Marta, M.; Reinhardt, T. P.; Schmidt, K.; Tain, J. L.; Takács, M. P.; Wagner, L.

A very low background level is a key requirement for underground nuclear astrophysics experiments.
A detailed gamma-background study with two escape-suppressed HPGe detectors has been performed at a medium deep underground site, namely the Reiche Zeche mine (148m) in Freiberg, Germany [1]. The new data complement a data set with the same detector at other underground sites [2,3].
Now, detailed background data are available at the Earth’s surface and at underground sites with depths of 45m, 148m, 1400m from one and the same escape-suppressed HPGe detector. This allows to investigate the effect of the active and passive shielding on the high energy (E_g > 3 MeV) laboratory background.
A detailed interpretation of the behaviour of different background components as a function of the underground depth will be presented.

In addition to this work with gamma-ray detectors, the neutron background has been studied by 3He counters from the BELEN neutron detector, equipped with polyethylene moderators of various thicknesses in the Felsenkeller laboratory (45m). By mean of the varied moderation, spectral information of the neutron flux is derived. The same detectors and same method were used previously deep underground in Canfranc/Spain (850m) to measure the neutron flux and spectrum [4]. This allows a direct comparison of the two sites.

  • Supported by the Helmholtz Association (HGF) through the Nuclear Astrophysics Virtual Institute (HGF VH-VI-417), and via the Helmholtz Young Investigators Group LISA (VH-NG 627).

[1] T. Szücs et al., Eur. Phys. J. A 51, (2015) 33
[2] T. Szücs et al., Eur. Phys. J. A 44, (2010) 513
[3] T. Szücs et al., Eur. Phys. J. A 48, (2012) 8
[4] D. Jordan et al., Astropart. Phys. 42, (2013) 1

Keywords: Underground; gamma background; neutron background; HPGe; 3He counter

  • Poster
    Nuclear Physics in Astrophysics Conference (NPA VII), 18.-22.05.2015, York, United Kingdom

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