MEASUREMENT OF THE HEAT DEFECT IN WATER AND A-150 PLASTIC FOR HIGH-ENERGY PROTONS, DEUTERONS, AND ALPHA-PARTICLES

An experimental set-up is described which allows the calorimetric dete rmination of the heat defect of solids and fluids relative to that of gilded copper which is used as the reference material. The calorimeter operates in a quasi-adiabatic mode and is suitable for protons, deute rons, a particles and other heavy ions with energies above 5 MeV. Corr ections have been made for secondary electron emission and also for he at losses due to the temperature gradient on the surface of the calori meter core. Measurements over 26 months indicate a repeatability of th e measured heat defect within 4 x 10(-3) (68% confidence level). Measu rements show an LET dependence of the heat defect for two different sa mples of A-150 plastic, and for distilled water.