Optimization of an active anti cosmic veto shielding

The active veto shielding of a low-level gamma spectrometer has been optimized to reduce the background in the interval 20-2700 keV by a factor of nine. The signal to noise ratio was increased, due to the reduction of electromagnetic interference coming from the power line, by using an uninterruptible power supply and specially designed line filters. The overall performance of the veto shielding was improved by using time spectroscopy to find the optimum time duration for the coincidence window.