Radioluminescence of ice containing MgCl2 and CaCl2

The efficiency of electron trapping and reactions in ice containing MgCl2 or CaCl2 (0.5-5 mol dm-3) and γ-irradiated at 77 K was investigated by isothermal-(ITL) and radiothermo-(RTL)-luminescence. Both ITL and RTL emissions are influenced by solute concentration in a similar way, revealing a maximum at ca 3.5 mol dm-3 MgCl2 and at ca 2.5 mol dm-3 CaCl2. The RTL emission exhibits two broad peaks. The low temperature peak RTL1 is only slightly dependent on matrix composition, whereas the position of the high temperature peak RTL11 shifts with glass transition point of the matrix. The influence of scavengers NaNO3 and CH3OH on radioluminescence (RL) was also investigated and found to be dependent on the nature of the cation. It is suggested that the RL emission is due to radiative recombination of et-(eir-, evis-) with H atoms, metal cations and Cl2- ion radicals. (author)