Gamma-Ray Measurements with a Magnetic Lens Spectrometer

Effects of instrument resolution and converter thickness on photoelectron lines have been investigated experimentally for gamma-radiation from 0.4 to 3 Mev. While determinations based on the high energy extrapolated edge of the lines seem to require no corrections for converter thicknesses, the peak value, which does require corrections, is in some cases more easily located. Peak shifts determined for thorium converters near 0.5 Mev are extrapolated to other energies by use of theoretical arguments. Values based on both types of determinations are quoted for gamma-radiation from the reactions ${\mathrm{Li}}^7$(p ${\mathrm{p}}^{\prime }$)${\mathrm{Li}}^{7*}$, ${\mathrm{Be}}^9$(d n)${\mathrm{B}}^{10*}$, and ${\mathrm{Co}}^{60}\left({\beta }^{-}\right){\mathrm{Ni}}^{60*}$. The corresponding excited level transition energies obtained are ${\mathrm{Li}}^{7*}$: 476.7±0.9 kev; ${\mathrm{B}}^{10*}$: 713.8±1.3 kev; ${\mathrm{Ni}}^{60*}$: 1172.4±1.8 kev and 1330.9±2.1 kev.