Radiations of AcK

The gamma rays of AcK (Fr²²³) were studied in a sodium iodide photomultiplier scintillation counter coupled to a 50-channel pulse-height analyzer. Photons of a 49.8-kev gamma ray appear in 40±{}10 percent and photons of an 80-kev gamma ray appear in 24±{}6 percent of the total beta disintegrations. In addition, low-intensity gamma rays appear at 215 and 310 kev. L x-radiation is present in about the same intensity as the 49.8-kev gamma ray. Gamma-gamma coincidence studies proved that the 49.8- and 80-kev radiations were not in coincidence. It was also shown that the 215- and the 50-kev gamma rays are not in coincidence. The L x-radiation was studied in a proportional counter coupled to a 50-channel analyzer and identified as radium x-rays. Since Th²²⁷ decays to the same daughter as does AcK some measurements were made on its gamma spectrum. Prominent photopeaks were observed at 49.8, 87, and 235 kev. The 235- and 49.8-kev gamma rays were observed to be in coincidence. The known decay data for AcK and Th²²⁷ cannot be fitted into a common decay scheme without additional information.