Measuring the ⁷Be Neutrino Flux From the Sun: Calibration of the Borexino Solar Neutrino Detector

The Borexino solar neutrino detector is a real-time liquid scintillator detector designed to measure sub-MeV neutrinos. With its unprecedented level of radio-purity, Borexino is poised to provide the most precise measurements to-date of solar neutrino and geo-antineutrino fluxes.

However, in order to reduce the systematic errors to sub-5% levels, the detector must be care- fully calibrated to understand, among other things, the position and energy reconstructions. To that end, the Virginia Tech component of the Borexino collaboration has constructed a system for deploying and locating calibration sources within the detector. The system was used in four separate calibration campaigns and deployed numerous sources in almost 300 locations throughout the detector. The data from the calibrations have already resulted in the reduction of several sources of systematic error by a factor of two or more. With the results from the calibration, the Borexino detector has entered a new era of low- energy, high-precision, neutrino detection.

This work was supported by NSF Grant 0802114