β spectrum following fission from 252Cf

The β spectrum from the fission products of 252Cf has been measured using a flat-field magnetic spectrometer. The shape of the β spectrum from 252Cf was measured at 5 field settings and the results combined to form a complete spectrum from 2.0 to 9.0 MeV (β total energy) with a total error of 3% at 3 MeV, rising to 6% at 5 MeV, 9% at 7 MeV, 15% at 8 MeV and 25% at 9 MeV. This experiment was motivated by the need to know the anti nu/sub e/ spectrum from the β decays of fission products in order to interpret the results of reactor based neutrino oscillation experiments. The anti nu/sub e/ spectrum can be calculated directly or converted from a measured β spectrum. This experiment is an additional check of these calculations and constitutes a complementary check of previous measurements of the β spectrum from other fissioning nuclei 235U, 239Pu, and 241Pu. We find a softer spectrum (fewer β's at high momenta) than predicted by the calculations, in agreement with earlier measurements in other nuclei by Schreckenbach et al., but in disagreement with earlier measurements by Borovoi et al. in 252Cf. Possible sources of the disagreement with the calculations and the earlier experiment and possible improvements to the experiment are discussed