Optical and scintillation properties of Pr-doped Li-glass for neutron detection in inertial confinement fusion process

Optical and scintillation properties of Pr-doped Li-glass, 20Al(PO ₃)₃-80LiF:Pr 3%, have been studied for applications in neutron detection systems. Based on optical transmission and reflectivity, the absorption coefficient and refractive index were calculated from the Beer Lambert law. The absorption edge was apparently shifted to the longer wavelength from 160 nm to 240 nm due to 4f → 5d transitions of Pr ions. The strong absorption peaks of praseodymium 4f → 4f transitions were observed from 420 nm to 500 nm and around 590 nm. The radio-luminescence spectrum excited by ²⁴¹Am 5.5 MeV α source was measured. Strong emission peaks were observed around 250 nm. The α-ray excited pulse height spectrum and decay kinetics were also examined. Light yield was estimated to be 400 ± 40 photons/5.5 MeV α and the main component of the decay time was evaluated to be about 12 ns. Furthermore, the pulse height spectrum of the glass excited by ²⁵²Cf neutrons was also measured, and the light yield was estimated to be 140 ± 10 photons/neutron.