CosI: Coherent Neutrino Scattering with Cesium Iodide

Nicole Fields, University of Chicago

Coherent neutrino scattering is a process predicted by the standard model of particle physics that has not yet been observed. For low enough energy neutrinos, O(10 MeV), their scattering cross section is predicted to increase with the square of the number of neutrons in a nucleus. Several difficulties must be overcome in order to observe coherent neutrino scattering, including finding a high-intensity source of these medium-energy neutrinos, a detector with a low enough threshold, and a low enough background. The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is a convenient source of medium-energy neutrinos and has the added benefit of a neutrino source with known time structure. CsI(Na) is an inorganic scintillator with a relatively high light yield of 39,000 photons/MeV and its emission spectrum is well matched with commonly used biakali photomultiplier tubes (PMTs). This gives it an effectively low energy threshold. As Cesium and Iodine are both heavy and have similarly large numbers of neutrons, this increases the coherent neutrino scattering signal over many other potential choices of target. With some care to choose reasonably radioclean materials, the background goals will be able to be achieved. CsI(Na) is an ideal detecting material to look for coherent neutrino scattering.

Abstract Author(s): N. E. Fields, J. I. Collar, T. W. Hossbach