March 20, 2019 Preprint Open Access

CYGNO Conceptual Design Report

Baracchini E.; Bedogni R.; Bellini F.; Benussi L.; Bianco S.; Bignell L.; Caponero M.; Cavoto G.; Di Marco E.; Eldridge C.; Ezeribe A.; Gargan R.; Gamble T.; Gregorio G.; Lane G.; Loomba D.; Lynch W.; Maccarrone G.; Marafini M.; Mazzitelli G.; Messina A.; Mills A.; Miuchi K.; Petrucci F.; Piccolo D.; Pinci D.; Phan N.; Renga F.; Saviano G.; Spooner N.; Thorpe T.; Tommassini S.; Vahsen S.

The conceptual design of the experiment named CYGNO (a CYGNUs module withOptical readout) is presented here. CYGNO aims to make significant advances in the technology of single phase gas-only time projection chambers (TPC) for the specific application of rare scattering events detection. In particular it will focus on a read-out technique based on the GEM amplification of the ionisation and on the visible light collection with a sub-mm position resolution by sCMOS camera. This type of readout - in conjunction with a fast light detection - will allow to reconstruct three dimensional (3D) images of the recoiling particles with high precision, offering new ways to distinguish the electron and nuclear recoils. The recoil direction resolution is also being investigated as a further tool to reject neutral background in the detection of Galactic Dark Matter (DM) particles. The final goal is to build and operate a high resolution gas TPC detector at the 50 kg scale for the directional search of a DM signal, in underground Laboratori Nazionali del Gran Sasso. In order to achieve this very demanding goal, we are going to develop firstly a 1 m³ volume, 1 kg mass detector based on these concepts, to assess on a real underground experiment the design performances and capabilities of our approach, while at the same time testing innovative techniques and methods to reach the 50 kg scale. This project is part of the world-wide effort of the CYGNUS collaboration to define an optimal DM detection scheme sensitive to DM direction, towards a one-ton gas TPC nuclear recoils Sobservatory.