UCN detection with 6Li-doped glass scintillators

We report the results of test measurements aimed at determining the performance of 6Li-doped glass scintillators for ultra-cold neutron detection. Investigations have mainly focused on the reduction of the gamma-ray sensitivity of the scintillators. The probability of gamma interaction has been considerably lowered using very thin glasses. For signals corresponding to full-energy deposition, a background count rate of 8x10-3 s-1 was obtained for a shielded 0.5 cm3 GS10 scintillator located near the PF2 turbine at ILL. The neutron-gamma separation has further been improved using a stack with an 6Li-depleted scintillator and an 6Li-enriched one. Neutron captures leading to partial energy deposition (so-called 'edge events') have strongly been reduced resulting in a clear separation between the neutron and the gamma contributions.