The LENS Experiment - A Brief Introduction
The purpose of the LENS experiment is to measure the Neutrino Luminosity of the sun with high precision. Currently the best experimental value for the ratio of Neutrino Luminosity and Photon Luminosity is:
The LENS detector is being designed to measure the low energy part of the solar neutrino spectrum, including the pp-Neutrinos which dominate the total neutrino flux:
The experimental tool to detect solar neutrinos is the tagged capture of the neutrino on 115In via charged current interaction:
The main problem in developing the LENS detector is the beta-decay of 115In with a lifetime of 6.4e14 years and a beta endpoint energy of 498.8 keV:
The solar neutrino spectrum as it will be measured by LENS:
The activity of natural Indium in a detector with 10t In loading will be ~2.5 MHz. This requires a detector design with high granularity, to prevent In beta decays from acting as false tags. A design currently being developed is the Scintillation Lattice Chamber:
The detecotor volume is separated into smaller volumes (cells) by layers of double-film with an airgap in between, which will allow for total internal reflection at the film/air interface. Light will be prevented from isotropic propagation in this setup, instead it will be channeled along rows of cells. Photomultiplier tubes at the ends of each row will detect the light and allow pixelated position reconstruction of each event, with a spatial resolution of the size of one cell.
Page modified May 19, 2006
