Luminescence and Scintillation Properties of Novel Disodium Dimolybdate (Na₂Mo₂O₇) Single Crystal

The luminescence and scintillation properties of novel Na₂Mo₂O₇ (NMO) crystals grown by two different techniques, the conventional Czochralski and the low-thermal-gradient Czochralski techniques, were studied. The transmittances of the NMO crystals were measured at room temperature. The luminescence properties and decay times of the crystals from room temperature 300 to 10 K were measured by using an LED diode emitting at the wavelength of 280 nm. Very weak luminescence was observed at the room temperature. The luminescence, however, was enhanced significantly at lower temperatures. The crystals showed a red emission peak of 663 nm at 10 K. The scintillation decay time was 2 μs at room temperature and was increased to 750 μs at 10 K. Low-temperature thermally stimulated luminescence measurements were carried out to investigate the presence of trap centers in the grown crystal. The scintillation light yield of the scintillator was measured by a photon counting technique using a ⁹⁰Sr beta source in the same temperature range from 300 to 10 K. The light yields of the NMO crystals grown at two different institutes were also compared with a standard CaMoO₄ crystal.