https://doi.org/10.1140/epjc/s10052-019-7160-2
Regular Article - Experimental Physics
Neutron-induced background in the CONUS experiment
1
Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg, Germany
2
Preussen Elektra GmbH, Kernkraftwerk Brokdorf, Osterende, 25576, Brokdorf, Germany
3
Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116, Braunschweig, Germany
* e-mail: janina.hakenmueller@mpi-hd.mpg.de
Received:
15
April
2019
Accepted:
19
July
2019
Published online:
21
August
2019
CONUS is a novel experiment aiming at detecting elastic neutrino–nucleus scattering in the almost fully coherent regime using high-purity germanium (Ge) detectors and a reactor as antineutrino source. The detector setup is installed at the commercial nuclear power plant in Brokdorf, Germany, at a short distance to the reactor core to guarantee a high antineutrino flux. A good understanding of neutron-induced backgrounds is required, as the neutron recoil signals can mimic the predicted neutrino interactions. Especially events correlated with the reactor thermal power are troublesome. On-site measurements revealed such a correlated, highly thermalized neutron field with a maximum fluence rate of 
. These neutrons, produced inside the reactor core, are reduced by a factor of 
on their way to the CONUS shield. With a high-purity Ge detector without shield the 
-ray background was examined including thermal power correlated 
decay products and neutron capture -lines. Using the measured neutron spectrum as input, Monte Carlo simulations demonstrated that the thermal power correlated field is successfully mitigated by the CONUS shield. The reactor-induced background contribution in the region of interest is exceeded by the expected signal by at least one order of magnitude assuming a realistic ionization quenching factor.
© The Author(s), 2019
