Many experiments looking for dark matter are aiming to get the ton scale in the
However, it is well known that scaling dark matter detectors to higher mass is
not a sufficient condition for sensitivity and that an equally important condition
is to simultaneously keep the background low, in particular the ultimate
background, namely the fast neutron background induced by muons.
In this presentation we study the possibility of using the existing structure of a
running experiment, the LVD supernova observatory at the INFN Gran Sasso
National Laboratory, as an active shield and veto for the muon-induced
In our vision LVD could become (without affecting in any way its main purpose
of SN neutrino telescope) a ‘host’ for a relatively compact but massive
experiment looking for rare events.
The LVD experiment consists of a 1000 ton liquid scintillator detector with a
highly modular structure, being made of 3 identical towers, each one composed
by 35 active modules.
The empty volume that can be obtained removing 2 modules from the most
internal part of the detector is 2.1m x 6.2m x 2.8m; we will call it “LVD core
We have evaluated the active vetoing and shielding power of LVD, with a
detailed MC simulation (based on Geant4) of the detector and the rock that
surrounds it. We have generated cosmic muons with energy spectrum and
angular distribution sampled accordingly to what is expected in the LNGS
underground laboratory (=270 GeV). The number and energy spectrum of
the muon-induced neutrons that enter the LVD-CF has been calculated.
The results show that the flux of neutrons that are not associated with a visible
muon in LVD is very low; it results equivalent to the one present in a much
deeper underground laboratory, i.e. Sudbury.
Moreover we will present the results of on-going measurements about the
gamma contamination inside the LVD-CF: the gamma ray intensity inside the
LVD-CF is reduced by a factor greater than 10 with respect to the one
measured outside the LVD detector.