Scintillation Properties of CsI:Na, $^{133}$ Ba Crystal

In Hyperball-J experiments, the lutetium oxyorthosilicate (Lu 2 SiO 5 :Ce, LSO) scintillators are constantly used to monitor and calibrate the Ge detectors. The LSO crystal has 176 Lu as a natural radioactive source. A new CsI:Na crystal that contains a 133 Ba radioactive source was developed in this study. This developed crystal can be used for detector calibration instead of LSO scintillators. The crystal was grown using a 2-zone vertical Bridgman method with a pulling speed of 0.5 mm/h. The CsI:Na, 133 Ba crystal was cut to Φφ 10 mm x 5 mm. Under X-ray excitation, the emission band of the crystal was observed between 330 nm and 650 nm. The scintillation properties of the CsI:Na, 133 Ba crystal such as light yield, energy resolution and decay time, were also measured using a 137 Cs γ-ray source. A High Purity Germanium (HPGe) detector was used to estimate the radioactivity in the crystal. The γ-ray peaks were identiηed from 133 Ba decay in the CsI:Na, 133 Ba crystal with a HPGe detector.