A fission-fragment detection system was designed and built at The George Wa
shington University, to be used in photofission experiments at the Saskatch
ewan Accelerator Laboratory and the Jefferson Laboratory. The fission fragm
ents were detected using parallel-plate avalanche detectors with anode wire
grids. An array of several target-detector pairs was mounted inside a low-
pressure reaction chamber. The results of calibrations of the detectors usi
ng a Cf-252 source and their performance with a bremsstrahlung photon beam
during the experiments are presented. (C) 2000 Elsevier Science B.V. All ri
ghts reserved.