Study of Time and Spatial Resolution of Fast Optical Signal in LIME, a Fifty Liters CYGNO Prototype

The proposal of CYGNO experiments, is the construction of one cubic meter, single-phase, gas-only Time Projection Chambers (TPCs) for Directional Dark Matter search. The particularity of CYGNO is the read-out technique based on Micro Pattern Gas Detector (MPGD) amplification of the ionization and on the collection of the yielded visible light by a scientific CMOS camera with a sub-mm position resolution. Four PMTs, arranged on the four sides of the detector, work as the trigger and are used to calculate the third coordinate of the tracks, to identify the electron and the nuclear recoils. The center of gravity of PMTs enables us to quickly identify the position of the track on the camera pictures and speed up the online analysis. In this work, the time and spatial resolution of the system are studied on LIME-2, the new 50 liters prototype, using the same readout electronics of the CYGNO DAQ system.