Measuring the low energy solar neutrino spectrum with the LENS experiment

The Low-Energy Neutrino Spectroscopy (LENS) experiment is designed for a precision measurement in real time of the fluxes of low energy solar neutrinos (pp, $^7$Be, pep, and CNO, comprising $> 99 \% $ of the solar neutrino energy) via charged-current capture on Indium-115 (with threshold of 114~keV). LENS will allow a comparison of the neutrino and photon luminosities of the sun that will test the basic assumptions of solar astrophysics and the overall validity of the MSW-LMA neutrino model. The individual flux results will improve limits on $\theta_{12}$ and the pp spectrum can directly probe the temperature profile of fusion energy production. A detector technology, utilizing a novel optical segmentation method with indium-loaded liquid scintillator has been developed. A modest 1~m$^3$ prototype (miniLENS), in development for installation in the Kimballton Underground Research Facility (KURF), will demonstrate experimental feasibility and will allow for optimization for a 200~ton, full-scale LENS experiment.