The $\hat{I}½$-cleus experiment: A gram-scale fiducial-volume cryogenic detector for the first detection of coherent neutrino-nucleus scattering

Abstract

We discuss a small-scale experiment, called $\hat{I}½$-cleus, for the first detection of coherent neutrino-nucleus scattering by probing nuclear-recoil energies down to the 10 eV-regime. The detector consists of low-threshold CaWO${}_4$ and Al${}_2$O${}_3$ calorimeter arrays with a total mass of about 10 g and several cryogenic veto detectors operated at millikelvin temperatures. Realizing a fiducial volume and a multi-element target, the detector enables active discrimination of ${\hat{I}}^3$, neutron and surface backgrounds. A first prototype Al${}_2$O${}_3$ device, operated above ground in a setup without shielding, has achieved an energy threshold of $\sim 20$ eV and further improvements are in reach. A sensitivity study for the detection of coherent neutrino scattering at nuclear power plants shows a unique discovery potential (5$\ddot{I}ƒ$) within a measuring time of $\lesssim 2$ weeks. Furthermore, a site at a thermal research reactor and the use of a radioactive neutrino source are investigated. With this technology, real-time monitoring of nuclear power plants is feasible.

14 pages, 19 figures