The LVD Core Facility: a study of LVD as muon veto and active shielding for dark matter experiments

TL;DR

This paper investigates using the LVD supernova observatory as an active muon veto and shield to reduce background noise for dark matter experiments, demonstrating significant neutron and gamma background suppression through simulations and measurements.

Contribution

It presents a novel approach to repurposing the LVD detector as an active shielding and veto system for dark matter searches without disrupting its primary function.

Findings

Neutron flux reduced by a factor of 50, comparable to deeper underground labs.

Gamma contamination inside the LVD Core Facility is reduced by over 10 times.

MC simulations confirm the effectiveness of LVD as a muon veto and shield.

Abstract

In this study we explore 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 background. 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 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 Facility (LVD-CF). 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. The results show that the flux of neutrons that are not associated with a visible muon in LVD is very low; it results reduced by a factor 50, equivalent to the one present in a much deeper underground laboratory, i.e. Sudbury. Moreover we present the results of on-going measurements about the gamma contamination inside the LVD-CF: it is reduced by a factor greater than 10 with respect to the one measured outside the LVD detector.