IMPROVED CALCULATION OF THE PROMPT FISSION NEUTRON SPECTRUM FROM THE SPONTANEOUS FISSION OF ^{252}Cf: PRELIMINARY RESULTSTheoretical Division, Los Alamos National Laboratory Los Alamos, New Mexico, USA An improved calculation is presented for the prompt fission neutron spectrum N(E) from the spontaneous fission of ^{252}Cf. In this calculation the fission-spectrum model of Madland and Nix is used, but with several improvements leading to a physically more accurate representation of the spectrum. Specifically, the contributions to N(E) from the entire fission-fragment mass and charge distributions will be calculated instead of calculating on the basis of a seven-point approximation to the peaks of these distributions as has been done in the past. Therefore, values of the energy release in fission, fission-fragment kinetic energy, and compound nucleus cross section for the inverse process will be considered on a point-by-point basis over the fragment yield distributions instead of considering averages of these quantities over the peaks of the distributions. Preliminary results will be presented and compared with a measurement, an earlier calculation, and a recent evaluation of the spectrum. KEYWORDS: calculation, prompt fission neutron spectrum, spontaneous fission, ^{252}Cf |