An Aboveground Pulse-Tube-Based Bolometric Test Facility for the Validation of the LUMINEU ZnMoO4 Crystals

The LUMINEU project aims at developing a pilot double beta decay experiment using scintillating bolometers based on ZnMoO4 crystals enriched in 100Mo. In the next months regular deliveries of large-mass ZnMoO 4 crystals are expected from the Nikolaev Institute of Inorganic Chemistry (Novosibirsk, Russia). It is therefore crucial for the LUMINEU program to test systematically and in real time these samples in terms of bolometric properties, light yield and internal radioactive contamination. In this paper we describe an aboveground cryogenic facility based on a dilution refrigerator coupled to a pulse-tube cooler capable performing these measurements. A 23.8 g ZnMoO4 crystal was fully characterised in this setup. We show also that macro-bolometers can be operated with high signal-to-noise ratio in liquid-free dilution refrigerators. © 2014 Springer Science+Business Media New York.