THE EFFECT OF DEPOSITION RATE AND SAMPLE THICKNESS ON THE LUMINESCENCE EMITTED BY ELECTRON-IRRADIATED POLYCRYSTALLINE H2O ICE

The luminescence arising from the excitation by 0.53 MeV electrons of vacuum deposited polycrystalline ice at 77 K, has been studied as a fu nction of deposition rate and ice thickness. Changes in deposition rat e from 0.03 to 17 mm h(-1), at various constant sample thicknesses, af fected the luminescence intensity, I, but did not significantly affect the decay half-life, nor C in the equation l = A + B(1 - C-n) for the dependence of light intensity, I, on the number of electron pulses, n . Increases in ice thickness from 0.25 mu m to 5 mm caused: (i) an inc rease in luminescence intensity to a plateau value at a thickness arou nd 2 mm; (ii) a blue-shift in the spectral maximum from 405 to 385 nm; and (iii) an increase in the decay half-life from 90 to 160 ns.