The Low Energy Neutrino Spectroscopy (LENS) Project

The goal of the LENS project is to measure, in real time, the primary low energy (sub-MeV) solar neutrino spectrum, with special attention to the pp- and ⁷Be neutrinos. The detector is an indium based liquid scintillator.

The main reaction is:
ν_e + ¹¹⁵In → e^- (solar signal) + 2 delayed γ (tag) + ¹¹⁵Sn

The inverse EC interaction of the neutrino with the target nucleus followed by coincident γ-emission provide a powerful signature of ν_e interaction compared to background events.

LENS will determine the spectral shape of the low energy solar neutrino spectrum for the first time. Up until now we have only seen the higher-energy ⁷Be, CNO, and pep portions of the spectrum. The low-energy part of the neutrino spectrum is very important, since the Sun's energy is primarily produced in the pp-chain, which produces neutrinos only in low energy part of the spectrum. Measuring these neutrinos probes the dominant energy production mechanism in the sun. With new data on the low energy band of the spectrum we can answer questions such as: Is the Sun getting hotter? Is there sub-dominant non-nuclear source of energy in the Sun?

The LENS design is a cubic lattice of non-hybrid (InLS only) which should have 56-65% detection efficiency. The cubic lattice structure of LENS will allow us to pin down the location of an event to within millimeters.

LENS will be installed at the DUSEL facility.