Energy spectra of long range alpha particles for different fragment charges in the fission of 252Cf

A three parameter experiment to measure the energy spectra of long range alpha (LRA) particles in the fission of 252Cf for different fragment charges has been performed. The fragment charges were determined by measuring the energies of the emitted K X-rays. The experiment employed a source of strength 106 fissions/minute sandwiched between two 1 mil Al foils, to measure K X-ray spectra from stopped fragments in order to eliminate Doppler broadening. The energies of the fragment K X-rays were measured with a cooled Si(Li) X-ray spectrometer, and the LRA energies were measured with a surface barrier detector. Whenever, and X-ray-alpha coincidence occurred, the pulse heights of the two detecrors, and the time interval between the two pulses were recorded on a magnetic tape. The analysis was carried out for events in the peak of the time spectra corresponding to a time resolution of 2tau approximately equal to 75 nsec. The LRA energy spectra for different fragment charges obtained by the computer analysis of the data has been presented and discussed. (author)