Secondary scintillation yield from GEM electron avalanches in - and - -isobutane for CYGNO — Directional Dark Matter search with an optical TPC

• DOI: 10.1016/j.physletb.2024.138759
• Publication Date: 2024-05-31T05:49:51Z
• Authors: F.D. Amaro; E. Baracchini; L. Benussi; S. Bianco; C. Capoccia; M. Caponero; D.S. Cardoso; G. Cavoto; A. Cortez; I.A. Costa; G. D'Imperio; E. Dané; G. Dho; F. Di Giambattista; E. Di Marco; F. Iacoangeli; H.P. Lima Júnior; G.S.P. Lopes; G. Maccarrone; R.D.P. Mano; R.R. Marcelo Greg...; D.J.G. Marques; G. Mazzitelli; A.G. McLean; A. Messina; C.M.B. Monteiro; R.A. Nobrega; I.F. Pains; E. Paoletti; L. Passamonti; F. Petrucci; S. Piacentini; D. Piccolo; D. Pierluigi; D. Pinci; A. Prajapati; F. Renga; R. J.d.C. Roque; F. Rosatelli; A. Russo; G. Saviano; N.J.C. Spooner; R. Tesauro; S. Tomassini; S. Torelli; J.M.F. dos Santos
• Keywords: Isobutane

CYGNO is an international collaboration with the aim of operating a optical time projection chamber (TPC) for directional Dark Matter (DM) searches and solar neutrino spectroscopy, to be deployed at Laboratori Nazionali del Gran Sasso (LNGS). A / (60/40) mixture used, along triple Gas Electron Multiplier (GEM) cascade amplify ionization signal. The scintillation produced in electron avalanches read out using scientific complementary metal–oxide–semiconductor (sCMOS) camera. This solution has proven provide very high sensitivity interactions few energy range. inclusion hydrogen-based gas will offer even lighter target, resulting more efficient transfer DM particle collision, consequently, lower detection threshold. Additionally, longer track lengths light nuclear recoils are easier detect clearer direction. However, addition such contribute quenching scintillation, jeopardizing TPC performance. In this work, we demonstrate feasibility adding 1% 5% isobutane by measuring respective absolute yield output. overall charge not drastically suppressed due addition. presence Penning from excited He atoms molecules increases number electrons avalanches, partially compensating loss quenching. For highest applied GEM voltage, total photons avalanche per deposited absorption region presents decrease only factor about three, 2.30(20)×104 8.2(4)×103 , as content 0 5%. quantification visible component shows that quenches both ultraviolet (UV) emitted /.