Lithium Aluminate Crystals as Scintillator for Thermal Neutron Detection

Undoped and Cu
⁺
-doped lithium aluminate LiAlO
₂
singe crystals have been grown using micro-pulling down (μ -PD) technique. After cutting and polishing, optical properties and scintillation characteristics of the crystals were examined. From the transmittance measurements, Cu
⁺
-doped crystal showed absorption band around 270 nm, which is corresponding to the transition between Cu
⁺
3d
¹⁰
and 3d
⁹
4s states. Ultra violet emission peak appeared around 360 nm under 270 nm excitation. The emission decay time was calculated to be about 17.3 μs.
²⁴¹
Am 5.5 MeV alpha-ray excited radioluminescence spectra exhibited intense luminescence band at 360 nm due to the Cu
⁺
3d
⁹
4s-3d
¹⁰
transitions. By the pulse height spectra
²⁵²
Cf neutron source excitation, the scintillation light output of Cu
⁺
-doped LiAlO
₂
was found to be about 8700 ph/n.