Searching for WIMPs with TREX-DM: achievements and challenges

• Published in: Journal of instrumentation Vol. 19; no. 5; p. C05029
• Main Authors: Castel, J.F., Cebrián, S., Dafni, T., Díez-Ibáñez, D., Ezquerro, A., Galán, J., García, J.A., Irastorza, I.G., Jiménez, M., Luzón, G., Margalejo, C., de Mira, A., Mirallas, H., Obis, L., Ortiz de Solórzano, A., Pérez, O., Ruz, J., Vogel, J.
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.05.2024
• Subjects: Argon; Dark Matter detectors (WIMPs, axions, etc.); Gas mixtures; Materials selection; Micropattern gaseous detectors (MSGC, GEM, THGEM, RETHGEM, MHSP, MICROPIC, MICROMEGAS, InGrid, etc); Neon; Particle tracking detectors; Sensors; Single electrons; Target detection; Time projection chambers
• ISSN: 1748-0221; 1748-0221
• DOI: 10.1088/1748-0221/19/05/C05029

Abstract The TREX-DM detector, a low background chamber with microbulk Micromegas readout, was commissioned in the Canfranc Underground Laboratory (LSC) in 2018. Since then, data taking campaigns have been carried out with argon and neon mixtures, at different pressures from 1 to 4 bar. By achieving a low energy threshold of 1 keV ee and a background level of 80 counts keV -1 kg -1 day -1 in the region from 1 to 7 keV ee , the experiment demonstrates its potential to search for low-mass WIMPs. Two of the most important challenges currently faced are the reduction of both, background level and energy threshold. With respect to the energy threshold, recently a new readout plane is being developed, based on the combination of Micromegas and GEM technologies, aiming to have a pre-amplification stage that would permit very low energy thresholds, close to the single-electron ionization energy. With respect to the background reduction, apart from studies to identify and minimize contamination population, a high sensitivity alpha detector is being developed in order to allow a proper material selection for the TREX-DM detector components. Both challenges, together with the optimization of the gas mixture used as target for the WIMP detection, will take TREX-DM to explore regions of WIMP's mass below 1 GeV c -2 .