(e, 2e) Experiments on cadmium autoionizing levels

We have extended our previous experimental investigations of coherent excitation, by electron impact, of Cd J = 0, 1, 2 autoionizing levels. The use of a position sensitive detector, in the ejected-electron channel, has led to higher count rates and a greatly improved energy resolution of 0.04 eV. The new data collection system permits the simultaneous acquisition of both ejected-electron and (e, 2e) energy spectra. The non-coincident spectra are used to normalize and align, with high accuracy, (e, 2e) spectra taken at ejected-electron angles 180 degrees apart; the difference between these spectra then yields the interference spectrum. We will present new high resolution spectra for ejected- electron directions along the momentum-transfer axis; these show the (J = 1) x (J = 2) + (J = 1) x (J = 0) interference effects. We will also present spectra obtained for open-quotes magic angleclose quotes ejected-electron directions with respect to the momentum transfer axis; these experiments isolate the (J = 1) x (J = 0) interference