Characterization of a medium size Xe/TMA TPC instrumented with microbulk Micromegas, using low-energy γ-rays

Álvarez Puerta, Vicente
Borges, Filipa I.G.M.
Cárcel García, Sara
Castel, J.
Cebrián, Susana
Cervera Villanueva, Anselmo
Conde, Carlos A.N.
Dafni, Theopisti
Dias, T.H.V.T
Díaz Medina, José
Egorov, M.
Esteve, Raúl
Evtoukhovitch, P.
Fernandes, L.M.P.
Ferrario, Paola
Ferreira, Antonio Luis
Freitas, Elisabete D.C.
Gehman, Victor M.
Gil Ortiz, Alejandro
Goldschmidt, Azriel
Gómez, H.
Gómez Cadenas, Juan José
González-Díaz, Diego
Gutiérrez, Rafael María
Hauptman, John M.
Hernando Morata, J.A.
Herrera, D.C.
Iguaz, F.J.
Irastorza, Igor Garcia
Jinete, M.A.
Labarga, Luis A.
Laing, Andrew
Liubarsky, Igor
Lopes, J.A.M.
Lorca Galindo, David
Losada, Marta
Luzón, Gloria
Marí, A.
Martín-Albo Simón, Justo
Martínez Pérez, Alberto
Martínez Lema, Gonzalo
Miller, Tom P.
Moiseenko, A.
Monrabal Capilla, Francesc
Monteiro, Cristina M.B.
Mora, Francisco José
Moutinho, L.M.
Muñoz Vidal, J.
Natal da Luz, H.
Navarro, G.
Nebot Guinot, Miquel
Nygren, David R.
Oliveira, Carlos A.B.
Palma, R.
Pérez, Javier Martin
Pérez Aparicio, J.L.
Renner, Joshua
Rodríguez, Ángel Y.
Santos, Filomena P.
dos Santos, Joaquim M.F.
Seguí, Laura
Serra Díaz-Cano, Luis
Shuman, Derek B.
Simón Estévez, Ander
Sofka, C.
Sorel, Michel
Toledo, J.F.
Tomás, A.
Torrent Collell, Jordi
Tsamalaidze, Zviadi
Vázquez, D.
Veloso, João F.C.A.
Villar, José Ángel
Webb, R.C.
White, James T.
Yahlali Haddou, Nadia
Aznar, F.
Calvet, D.
Druillole, F.
Ferrer-Ribas, E.
García, J.A.
Giomataris, I.
Gracia, J.
Le Coguie, A.
Mols, J.P.
Pons, P.
Ruiz-Choliz, E.
NEXT-MM is a general-purpose high pressure (10 bar, ~ 25 l active volume) Xenon-based TPC, read out in charge mode with an 0.8 cm × 0.8 cm-segmented 700 cm2 plane (1152 ch) of the latest microbulk-Micromegas technology. It has been recently commissioned at University of Zaragoza as part of the R&D of the NEXT 0νββ experiment, although the experiment's first stage is currently being built based on a SiPM/PMT-readout concept relying on electroluminescence. Around 2 million events were collected during the last months, stemming from the low energy γ-rays emitted by a 241Am source when interacting with the Xenon gas (Eγ = 26, 30, 59.5 keV). The localized nature of such events around atmospheric pressure, the long drift times, as well as the possibility to determine their production time from the associated α particle in coincidence, allow the extraction of primordial properties of the TPC filling gas, namely the drift velocity, diffusion and attachment coefficients. In this work we focus on the little explored combination of Xe and trimethylamine (TMA) for which, in particular, such properties are largely unknown. This gas mixture offers potential advantages over pure Xenon when aimed at Rare Event Searches, mainly due to its Penning characteristics, wave-length shifting properties and reduced diffusion, and it is being actively investigated by our collaboration. The chamber is currently operated at 2.7 bar, as an intermediate step towards the envisaged 10 bar. We report here its performance as well as a first implementation of the calibration procedures that have allowed the extension of the previously reported energy resolution to the whole readout plane (10.6% FWHM@30 keV) ​
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