S- AND P-WAVE NEUTRON SPECTROSCOPY .12. HIGHER RESOLUTION TECHNIQUES IN KEV REGION WITH WINDOWLESS GAS TARGETS

The relative total yield of the O18(p, n) reaction has been studied from threshold to 3.290 MeV with a proton resolution of about 1 11,000. A previously unreported resonance was observed and improved values of widths and energies were obtained for the other resonances. The Q value for the reaction was determined to be -2439 ± 1 keV which places threshold at 2576 ± 1 keV. The reaction took place in the windowless cryogenic target chamber. A gas handling system was developed to allow one liter of oxygen gas, 65% enriched in O18, to be cycled through the target chamber and recovered with a minimum of loss or dilution. The O18(p, n) neutrons were used in a series of transmission measurements to test the resolution capability of the gas target as a neutron source. Results were in good agreement with resolution predictions. Total neutron energy spreads were 250 eV and 500 eV at neutron energies of 30 keV and 525 keV respectively. © 1969.