GADZOOKS! Antineutrino Spectroscopy with Large Water Cerenkov Detectors

Abstract

We propose modifying large water Čerenkov detectors by the addition of 0.2% gadolinium trichloride, which is highly soluble, newly inexpensive, and transparent in solution. Since Gd has an enormous cross section for radiative neutron capture, with $\sum E_{\gamma }=8$ MeV, this would make neutrons visible for the first time in such detectors, allowing antineutrino tagging by the coincidence detection reaction ${\bar{\nu }}_e+p\to e^{+}+n$ (similarly for ${\bar{\nu }}_{\mu }$). Taking Super-Kamiokande as a working example, dramatic consequences for reactor neutrino measurements, first observation of the diffuse supernova neutrino background, Galactic supernova detection, and other topics are discussed.

4 pages, 1 figure, submitted to Phys. Rev. Lett. Correspondence to [email protected], [email protected]