Coincidence and Absorption Measurements onCs134,I124,Au199, andCa45

Abstract

The beta-ray spectrum of ${\mathrm{Cs}}^{134}$ was investigated by absorption and beta-gamma-coincidence measurements. Beta-rays of 0.60 Mev and about 90 kev were observed. In ${\mathrm{I}}^{124}$, the maximum energy of the beta-rays was found to be 2.30 Mev and beta-gamma-coincidences showed the beta-spectrum to be simple. A maximum gamma-ray energy of 2.24 Mev was observed with several lower energy gamma-rays indicated. Gamma-gamma-coincidences were found, but coincidences between beta-particles and internal conversion electrons could not be detected. ${\mathrm{Au}}^{199}$ exhibited a beta-ray of 0.32 Mev, and the beta-gamma-coincidence rate per beta-ray was independent of absorber thickness. A maximum gamma-ray energy of about 0.21 Mev was found by coincidence absorption of photoelectrons and coincidences between beta-particles and internal conversion electrons. Gamma-gamma-coincidences were obtained. The 43-minute isomeric state of Hg sometimes attributed to ${\mathrm{Hg}}^{199}$ was not observed to grow from ${\mathrm{Au}}^{199}$. ${\mathrm{Ca}}^{45}$ was found to have a single beta-ray of 0.22 Mev and no gamma-rays.