A pyroelectric calorimeter for studies of radiation induced thermal transients in thin films and at surfaces is described. The signal generation and detection process, as well as design criteria are briefly reviewed. Detailed data are presented whereby our design, which has found extensive utility, can be fabricated. This device is compatible with standard Inficonl quartz microbalance hardware and provides a sensitivity of several nanojoules at a time resolution of < 100 ns over a wide temperature and pressure range. © 1987, American Vacuum Society. All rights reserved.