Measurements of the Dielectric Properties of Irradiated Low-Loss by Microwave Reflectometry and Micro-Calorimetry

An rf reflectometer has been used to measure dielectric losses in alumina ceramics during irradiation by 3 MeV protons. The equipment was able to detect tan ȯ changes of 5×10−5, but calibration by micro-calorimetry revealed large systematic losses, up to 2.5×10−3 Irradiation at 300 K resulted in a progressive increase in dielectric loss but no prompt increments.