Study of the Broad Emission Wavelength of Lu $_{0.4}$Gd$_{1.6}$ SiO$_5$:Ce for APD Detection

The emission spectra for X-ray and UV excitation, decay curve for emission above 460 nm under gamma-ray excitation, and energy spectrum by using avalanche photodiode (APD) for excitation with
¹³⁷
Cs gamma-rays have been measured for Lu
_0.4
Gd
_1.6
SiO
₅
having 2.0 mol% Ce. The emission spectrum under X-ray excitation showed two peaks around 430 and 495 nm. The excitation-emission spectrum under UV excitation also had two peaks at 425 and 510 nm for excitation wavelength of 285 and 385 nm, respectively. There was no significant difference in decay constants of emission between the longer and shorter wavelength components. Energy resolution by using an APD was 8.0% for
¹³⁷
Cs gamma-ray excitation