CYGNO is developing a gaseous Time Projection Chamber (TPC), which will be hosted at Laboratori Nazionali del Gran Sasso, Italy, and will rely on a triple Gas Electron Multiplier (GEM) stack for charge multiplication and electroluminescence (EL) production. The EL will be collected with a high resolution scientific camera for particle identification and 2D track reconstruction, with the aim of discriminating nuclear recoils and their direction.
This work aims at determining how the addition of small percentages of isobutane to the He-CF4 (60/40) select CYGNO TPC gas mixture influences the EL yield, charge gain and energy resolution. A Large Area Avalanche Photodiode (LAAPD) was used to readout the EL produced in the avalanches of a single GEM. Isobutane fractions up to 5% were added to the CYGNO He/CF4 (60/40) base mixture.
Our results show that the inclusion of isobutane does not severely compromise the amount of EL photons detected, while maintaining the energy resolution and increasing the charge gain of the CYGNO He-CF4 (60/40) base mixture.