Precise Determination of Nuclear Reaction Energies and Measurements of Resonance Widths

An electrostatic analyzer with a radius of curvature of 2 meters and a deflection angle of 90° has been constructed and evaluated. It is used to provide an ion beam whose energy is precisely known and highly resolved. The absolute energy calibration is believed to be accurate to ±0.05%, and the inherent energy resolution is 0.01% per 0.010 in. of input slit separation. Proton bombarding energies have been determined for ($p, \gamma$) reactions on ${\mathrm{F}}^{19}$ at 340.5±0.3 kev, 483.6±0.3 kev, 872.4±0.4 kev; ${\mathrm{Al}}^{27}$ at 992.4±0.5 kev; ${\mathrm{Ni}}^{58}$ at 1424.1±0.7 kev, 1843.7±0.9 kev; and ${\mathrm{C}}^{13}$ at 1747.6±0.9 kev. Resonance widths have been measured for these reactions. They are 2.4±0.3 kev, 0.9±0.1 kev, 4.5±0.3 kev, 100±50 ev, 50±50 ev, 100±50 ev, and 75±50 ev, respectively. The ($p, n$) thresholds have been determined for ${\mathrm{Li}}^7$ at 1881.2±0.9 kev and ${\mathrm{C}}^{13}$ at 3237.2±1.6 kev.