Method to Reduce Noise for Measurement of $^7$Be and $^8$B Solar Neutrinos on Gallium-71

Abstract

Gallium solar neutrino experiments have historically used radiochemical counting to determine the event rate. A detector which directly measures the ejected electron and de-excitation gamma could reduce background counting rates by way of a double-pulse technique. We find this reduction could be as large as 10 orders of magnitude in a 100 ton detector. In this process, the detector measures the excited nuclear final state of the germanium after an electron neutrino interacts with gallium nucleus through the charged-current interaction. This results in a loss of approximately 90\% of the total neutrino signal, but higher energy processes are less suppressed. The neutrinos resulting from this higher energy selection are predominantly from the {}$^8$B and {}$^7$Be solar neutrino fluxes.