162232 20251017144631.0 doi 10.12688/openreseurope.19258.2 sideral 144770 ART-2025-144770 eng Castel Pablo, Juan Francisco Universidad de Zaragoza (orcid)0000-0003-3532-7540 Micromegas with GEM preamplification for enhanced energy threshold in low-background gaseous time projection chambers 2025 Access copy available to the general public Unrestricted Background We develop the concept of a Micromegas readout plane with an additional GEM preamplification stage placed a few millimetres above it to increase the maximum effective gain of the combined readout. Methods We implement it and test it in realistic conditions for its application to low-background dark matter searches like the TREX-DM experiment. For this, we use a Micromegas of Microbulk type, built with radiopure materials. Results We report on GEM effective extra gain factors of about 90, 50 and 20 in 1, 4 and 10 bar of Ar-1%iC4H10. These results are obtained in a small test chamber allowing for systematic scanning of voltages and pressures. In addition, a TREX-DM full-scale set-up has also been built and tested, featuring a replica of the fully-patterned TREX-DM Microbulk readout. Conclusions The results here obtained show promise to lower the threshold of the experiment down to 50 eV ee , corresponding to substantially enhanced sensitivity to low-mass WIMPs. info:eu-repo/grantAgreement/EC/H2020/101026819/EU/Low background techniques on particle detectors for Rare Event Searches/LOBRES This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 101026819-LOBRES info:eu-repo/grantAgreement/EC/H2020/788781/EU/Towards the detection of the axion with the International Axion Observatory/IAXOplus This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 788781-IAXOplus info:eu-repo/grantAgreement/ES/MICINN/PID2019-108122GB-C31 info:eu-repo/grantAgreement/ES/MICINN/PID2022-137268NB-C51 info:eu-repo/semantics/openAccess by https://creativecommons.org/licenses/by/4.0/deed.es info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Cebrián Guajardo, Susana Universidad de Zaragoza (orcid)0000-0002-6948-5101 Dafni, Theopisti Universidad de Zaragoza (orcid)0000-0002-8921-910X Díez Ibáñez, David Universidad de Zaragoza Galán Lacarra, Javier (orcid)0000-0001-7529-9834 García Pascual, Juan Antonio Universidad de Zaragoza (orcid)0000-0002-7399-7353 Ezquerro Sastre, Álvaro Universidad de Zaragoza (orcid)0009-0001-8374-6128 García Irastorza, Igor Universidad de Zaragoza (orcid)0000-0003-1163-1687 Luzón Marco, Gloria Universidad de Zaragoza (orcid)0000-0002-5352-1884 Margalejo Blasco, Cristina Universidad de Zaragoza (orcid)0000-0001-6213-5590 Mirallas Sánchez, Héctor Universidad de Zaragoza (orcid)0000-0002-9951-8680 Obis Aparicio, Luis (orcid)0000-0002-7990-2060 Ortiz de Solórzano, Alfonso Universidad de Zaragoza (orcid)0000-0001-8278-6032 Pérez Lázaro, Óscar Universidad de Zaragoza Porrón Lafuente, Jorge Universidad de Zaragoza Jiménez Puyuelo, María Universidad de Zaragoza (orcid)0009-0005-7060-5341 2004 X Universidad de Zaragoza Dpto. Física Teórica Proy. investigación HCA 2004 390 Universidad de Zaragoza Dpto. Física Teórica Área Física Atóm.Molec.y Nucl. 5 (2025), 53 Open Research Europe 2732-5121 3920284 http://zaguan.unizar.es/record/162232/files/texto_completo.pdf Versión publicada 1720040 http://zaguan.unizar.es/record/162232/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:162232 articulos driver 2025-10-17-14:26:24 ARTICLE