Preliminary Calibration of Spherical Proportional Counter for Low Energy Nuclear Recoils

International audienceNeutrino physics and dark matter detection are frontier topics of current particle physics. Good rock shielding, ultra low background and ultra low energy threshold are key factors to detect signals successfully from neutrino and WIMPs scattering in underground experiments. Thus, a novel large volume spherical proportional counter has been set up in IHEP, which adopted an ultra small front-end capacitor with ultra low energy threshold (few keV) and a single center dynode that creates a strong radial electric field. This simple and robust structure enable the signal to be read out through a single electronic channel. Charges deposited in the gaseous vessel, drifting to the central electrode followed by amplification and collection. In the preliminary calibration of the prototype, it can not only detect but also identify the alpha and neutron particles precisely. The pretest results and performance of the detector reveal its possible application for future neutron background, neutrino and dark matter measurement