Suppression of the slow component of scintillation light in

BaF 2 is a common scintillator material used for the detection of gamma radiation due to its relatively high stopping power, radiation hardness and high luminescence. BaF 2 is often used in gamma ray timing experiments because of the prompt decay component. It is well known that the light output from BaF 2 has two decay components: a prompt one at ∼ 220 nm with a decay constant of around 600 ps and a more intense, temperature dependent, slow component at ∼ 300 nm with a decay constant around 600 ns which hinders fast timing experiments. We report here the development of a gamma ray detector based on a BaF 2 scintillator crystal heated to 220 °C for which the intensity of the slow component is reduced to ( 1 ± 1 ) % . The analysis of the temperature dependent intensity using a model including a single thermally activated quenching mechanism is consistent with the slow component arising from a self-trapped exciton with an activation energy E = ( 0.25 ± 0.01 ) eV .