Assignment and Disintegration Scheme of the 6.75-Hour Molybdenum

Abstract

Contrary to previous reports, deuteron bombardment of molybdenum does not produce any measurable amount of the 6.75-hour Mo activity. The assignment of this activity has, therefore, been reinvestigated and correctly found to be still ${\mathrm{Mo}}^{93}$. Decay does not take place by positron emission or $K$-capture. A disintegration scheme has been worked out using absorption, beta-ray spectrograph, and coincidence counter measurements. By successive emission of three gamma-rays of energies 0.30, 0.70 and 1.7 Mev of which the first is about 90 percent internally converted, the 6.75-hour ${\mathrm{Mo}}^{93}$ passes into a long-lived isomeric state. Mo $K_{\alpha }$ x-rays resulting from the conversion have been found.