A spherical gaseous detector for physics with reactor neutrinos

Nuclear reactors are very intense sources of electron anti-neutrinos produced on an average 6 per fission. Some of the most important goals of neutrino physics such as study of short baseline reactor anti-neutrino anomaly, measurement of neutrino cross section on different targets, measuring neutrino magnetic moment with high precision, detecting sterile neutrinos could be carried out with nuclear reactors. A detector for neutrinos must have a large volume with very low noise and background rejection capabilities. It must be cost effective, modular and easy in operation. Spherical Gaseous Chamber Detector (SGCD) is one such detector that meets all above requirements. It is designed to have a small sphere (1-5 mm diameter) of solid pure copper as anode inside a very large sphere (0.5-1 meter diameter) of pure copper working as cathode. The gas to be filled in the chamber must have a stable drift velocity and minimum diffusion over the entire range of electric field. These properties can be controlled by a suitable gas mixture such as Ar:He: N2 in the ratio 200:50:1.5. When a neutrino interacts with the molecules of the filled gas, it creates electron ion pairs. The created electron will move towards the anode at the center of the sphere and will gain sufficient energy to create an avalanche that will make single peak strong signal. Other charged and neutral background particles entering the chamber will interact multiple times and hence the shape of signal will have multiple peaked. This difference in peak shapes will enable us to separate background from the signal using pulse shape discrimination (PSD) techniques. The sphere will be surrounded by a hexagonal shaped half cm thick boron loaded polyethylene (BLP) to provide stable structure