Development of dense scintillating hard fluoride glasses for the electromagnetic caorimeter of the proposed compact muon solenoid

Abstract

Hafnium based Heavy Metal Fluoride glasses have been produced and evaluated in a search for new dense scintillating materials. The principal motivation was the electromagnetic calorimeter of the Compact Muon Solenoid (CMS), a proposed detector for the Large Hadron Collider (LHC) at CERN, Geneva. Incorporating CeF 3 in these transparent glasses results in scintillators with fast time constants that are typical of crystalline CeF 3. Typical decay components of 9 ns (30 %) and 25 ns (70 %) have been measured. To record the time distribution of scintillation light, an extension to the single-photon method, has been developed, it is optimised for materials with low light output. An alternative acquisition system which used a Multi-Channel Scaler has been critically evaluated for this application. A low dose rate (1.2 rads- I) 60CO irradiation has been used to determine the radiation tolerance of the glasses. Radiation induced optical absorbance was predominantly located in the UV with tails extending into the visible region. These glasses show partial recovery of optical absorbance at room temperature. Compositional optimisation has shown that Indium and Cerium enhance radiation tolerance.