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arXiv · 2412.19864

Micromegas with GEM preamplification for enhanced energy threshold in low-background gaseous time projection chambers

J. Castel·S. Cebrián·T. Dafni·D. Díez-Ibáñez·J. Galán·J. A. García·A. Ezquerro·I. G Irastorza·G. Luzón·C. Margalejo·H. Mirallas·L. Obis·A. Ortiz de Solórzano·O. Pérez·J. Porrón·M. J. Puyuelo
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Abstract

Background: we develop the concept of a Micromegas (MICRO-MEsh GAseous Structure) readout plane with an additional GEM (Gas Electron Multiplier) preamplification stage placed a few mm above it, to increase the maximum effective gain of the combined readout. We implement it and test it in realistic conditions for its application to low-background dark matter searches like the TREX-DM experiment. Methods: for this, we use a Micromegas of microbulk type, built with radiopure materials. A small test chamber allowing for systematic scanning of voltages and pressures is used. 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. Results: we report on GEM effective extra gain factors of about 90, 50 and 20 in 1, 4 and 10 bar of Ar-1%iC$_{4}$H$_{10}$. 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 (Weakly Interacting Massive Particles).

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J. Castel, S. Cebrián, T. Dafni, D. Díez-Ibáñez, J. Galán, J. A. García, A. Ezquerro, I. G Irastorza, G. Luzón, C. Margalejo, H. Mirallas, L. Obis, A. Ortiz de Solórzano, O. Pérez, J. Porrón, M. J. Puyuelo. 2024-12-26. Micromegas with GEM preamplification for enhanced energy threshold in low-background gaseous time projection chambers. https://doi.org/10.12688/openreseurope.19258.2

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