Beta spectra following the spontaneous fission of 252Cf

Neutrino-oscillation studies using reactor sources can be made much more sensitive if the nu spectrum from the reactor is known. The fission of a heavy nucleus such as Cf or U creates neutron-rich nuclei so far from the valley of stability that their beta-decay spectra are not known. Thus a model must be employed to predict the overall beta-decay spectrum and the attendant nu spectrum. In order to test the reliability of the procedure in use the beta spectrum of the fission fragments following 252Cf fission is being measured to an accuracy of 3% in shape and 5% in total yield. An actively-collimated, flat-field beta spectrometer is used