engleski

Determination of widths of K-a transitions from radiative 2p-electron capture spectra

Radiative capture of a 2p-electron by the nucleus shows resonances at photon energies in the regions of Kalpha transitions. Shapes of the resonances depend strongly on the natural widths of the Kalpha lines. Measurements have been made using a pair of germanium detectors in a close 180 degrees geometry, in conjunction with a 128*512*512-channel coincidence system. Two-dimensional E1-E2 spectra (energies of photons detected in one and in the other detector) have been made. The E1-E2 spectra show prominent two-dimensional peaks due to the cascades of K X-rays and L X-rays. Radiative 2p-electron capture events are identified by the coincident detection of capture photons and L X-rays. The Lalpha, Lbeta and Lgamma lines are well separated. The spectrum in the band due to Lgamma X-rays shows a single peak at the energy of Kalpha2 X-ray line and a continuum above the peak. The shape of the spectrum allows the determination of the width of the Kalpha2 line. Similarly, the spectrum in the band due to Lalpha X-rays allows the determination of the width of the Kalpha1 line. Measurements of radiative capture of 2p- electrons have been made in 179-Hf and 201-Tl. The widths of the Kalpha transitions have been derived by fitting the theoretical spectra of radiative 2p-electron capture, modified for realistic Kalpha transition energies and for radiation damping. Somewhat smaller results have been obtained for the widths of the Kalpha lines than the previously reported values.

2p-electron radiative capture ; resonances ; natural widths of the Kalpha lines ; 179-Hf and 201-Tl decay

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