Figure 1

Radioactivity change of CsPs by heating. Radioactivity normalized by that before heating is shown as a function of heating temperature. In each heating operation, CsPs were heated up to the target temperature at 10 °C/min and cooled in air. Points connected by lines mean that heating and cooling were repeated at subsequently increasing target temperatures. Error bars are not shown in CsP-2 and 3 because their radioactivity was determined by IP autoradiography. The radioactivity of other CsPs was measured using a germanium detector.