Speaker
Description
Innovative experimental techniques are needed to further search for dark matter weakly interacting massive particles. The ultimate limit is represented by the ability to efficiently reconstruct and identify nuclear and electron recoil events at the experimental energy threshold. Gaseous Time Projection Chambers (TPC) with optical readout are very promising candidates thanks to the 3D event reconstruction capability of the TPC technique and the high sensitivity and granularity of last generation scientific light sensors. The Cygno experiment is pursuing this technique by developing a TPC operated with He/CF4 gas mixture at atmospheric pressure equipped with a Gas Electron Multipliers (GEM) amplification stage that produces visible light collected by scientific CMOS camera. The optical approach has so far only exploited the light produced during the avalanche processes in the GEM channels. In this contribution, we discuss recent measurements performed by the CYGNO collaboration which show the first evidence of additional luminescence in He/CF4 induced by electrons accelerated by a suitable electric field. The electron and photon yield has also been studied for gas mixtures with a small percentage of isobutane. We give an overview of the CYNGO project presenting the performances in terms of energy and spacial resolution of prototype detectors that have been built and operated so far. Finally, we illustrate the plan to construct a 1m3 demonstrator expected in 2021/22 aiming at a larger scale apparatus in a later stage.
