Disintegration Schemes of Radioactive Substances. V.I130

The disintegration of ${\mathrm{I}}^{130}$ was studied by spectrometer and coincidence techniques. The decay proceeds by two modes of negatron emission of maximum beta-ray energy 0.61±0.02 Mev and 1.03±0.02 Mev, respectively. The high energy spectrum represents 60±10 percent of the disintegrations and is accompanied by three gamma-rays of energies 0.537±0.005 Mev, 0.667 ±0.008 Mev, 0.744±0.010 Mev. The low energy spectrum is accompanied by these same three gamma-rays and, in addition, by a gamma-ray of energy 0.417±0.005 Mev. The coefficients of internal conversion in the $K$ shell are 0.0031, 0.0038, 0.0069, 0.012, (±20 percent) in order of decreasing gamma-ray energy. The conversion in the $L$ shell is much smaller. It is shown that the Fermi plot of the complex spectrum can be separated into straight lines which may be extrapolated to obtain the correct disintegration energies.