Neutron spectra of (p, n) reactions on copper nuclei

For the purpose of elucidating the mechanism of the (p, n) reaction on copper nuclei and determining the level density of 63Zn and 65Zn finite nuclei, the neutron spectra and their angular distributions at 6-9 MeV proton energy with 1 MeV pitch have been measured. The spectrum measurement for five angles from 30 deg to 150 deg with 30 deg interval has been performed at a time-of-flight spectrometer. Stilbene crystal of 63x39 mm dimension and PEM-30 have been used as a detector. Matalic foils have been used as targets, copper 63 target foil had 2.10 mg/cm2 thickness, basic isotope content - 97.4%, impurity 2.6% - copper 65. Copper 65 target foil had 2.53 mg/cm2 thickness, enrichment - 93.7% impurity 6.1% -copper 63. Differential and total cross sections of neutron yield with excitation of certain groups of finite nuclei levels zinc 63 and zinc 65 are obtained. The continuous part of the spectrum for 65Ca has been analyzed within the framework of a statistical model using the Weiskopf formula. The ''a''level density parameters found from spectra at 8 and 9 MeV proton energy are considerably less than the parameter found from the resonance data