# Monitoring of the thermal neutron flux in the LSM underground laboratory

3 CSNSM INSTR
CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse
5 CSNSM PS1
CSNSM - Centre de Sciences Nucléaires et de Sciences de la Matière, CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse
Abstract : This paper describes precise measurements of the thermal neutron flux in the LSM underground laboratory in proximity of the EDELWEISS-II dark matter search experiment together with short measurements at various other locations. Monitoring of the flux of thermal neutrons is accomplished using a mobile detection system with low background proportional counter filled with $^3$He. On average 75 neutrons per day are detected with a background level below 1 count per day (cpd). This provides a unique possibility of a day by day study of variations of the neutron field in a deep underground site. The measured average 4$\pi$ neutron flux per cm$^{2}$ in the proximity of EDELWEISS-II is $\Phi_{MB}=3.57\pm0.05^{stat}\pm0.27^{syst}\times 10^{-6}$ neutrons/sec. We report the first experimental observation that the point-to-point thermal neutron flux at LSM varies by more than a factor two.
Document type :
Preprints, Working Papers, ...
Domain :

http://hal.in2p3.fr/in2p3-00696140
Contributor : Sylvie Flores <>
Submitted on : Friday, May 11, 2012 - 8:26:09 AM
Last modification on : Tuesday, November 24, 2020 - 4:30:04 PM

### Identifiers

• HAL Id : in2p3-00696140, version 1
• ARXIV : 1001.4383

### Citation

S. Rozov, E. Armengaud, C. Augier, L. Bergé, Alain Benoit, et al.. Monitoring of the thermal neutron flux in the LSM underground laboratory. 2012. ⟨in2p3-00696140⟩

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