TREX-DM: a low background Micromegas-based TPC for low-mass WIMP detection

F J Iguaz,T Dafni,G Luzón,J A García,I G Irastorza,A Peiró,S Cebrián,J G Garza,J F Castel,F Aznar,A Lagraba

doi:10.1088/1742-6596/718/4/042026

F J Iguaz, T Dafni + Show 9 more

Open Access

https://doi.org/10.1088/1742-6596/718/4/042026

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Abstract

Dark Matter experiments are recently focusing their detection techniques in low-mass WIMPs, which requires the use of light elements and low energy threshold. In this context, we describe the TREX-DM experiment, a low background Micromegas-based TPC for low-mass WIMP detection. Its main goal is the operation of an active detection mass ~0.3 kg, with an energy threshold below 0.4 keVee and fully built with previously selected radiopure materials. This work describes the commissioning of the actual setup situated in a laboratory on surface and the updates needed for a possible physics run at the Canfranc Underground Laboratory (LSC) in 2016. A preliminary background model of TREX-DM is also presented, based on a Geant4 simulation, the simulation of the detector’s response and two discrimination methods: a conservative muon/electron and one based on a neutron source. Based on this background model, TREX-DM could be competitive in the search for low-mass WIMPs. In particular it could be sensitive, e.g., to the low-mass WIMP interpretation of the DAMA/LIBRA and other hints in a conservative scenario.

Highlights

The experimental e ort of Dark Matter searches [1] has focused for many years on the search for Weakly Interactive Mass Particles (WIMPs) of relatively large masses
We have considered two light gas mixtures at 10 bar: Ar+2%iC4H10 and Ne+2%iC4H10, which are good candidates to detect low-mass WIMPs and give a total active mass of 0.30 and 0.16 kg respectively
A wide range of materials and components used in TREX-DM detector has been measured in terms of radiopurity: the vessel, the field cage, the shielding, the readout planes and the electronics acquisition system

Summary

Introduction

The experimental e ort of Dark Matter searches [1] has focused for many years on the search for Weakly Interactive Mass Particles (WIMPs) of relatively large masses (of around 50 GeV or larger). Recent advances in radiopure Micromegas readout planes [4], in the selection of radiopure materials for TPCs [5] and in electronics [6, 7, 8] are improving the low-background Prospects and scalability of Micromegas-based TPCs. As part of the T-REX project2, a prototype to assess the feasibility of a low-mass WIMP detector has been developed: TREXDM.

Results

Conclusion