Scintillation properties of Ce3+-doped, Pr3+-doped calcium orthoborate

To develop new scintillators for thermal neutron detection, we investigated optical and scintillation properties of Ce
³⁺
-doped, Pr
³⁺
-doped Ca
₃
(BO
₃
)
₂
single crystals grown by the micro-pulling down (μ-PD) method. In optical transmission spectra, the absorption was observed around 275 and 345 nm correspond to the transition from the 4f ground state levels
²
F
_5/2
,
²
F
_7/2
to 5d excited state of Ce
³⁺
and Pr
³⁺
transition from the ground state
³
H to 5d state around 210-245 nm, respectively. The radioluminescence spectra showed intense peak around 400 nm (Ce
³⁺
:CBO) and 260-310 nm (Pr
³⁺
: CBO) under
²⁴¹
Am 5.5 MeV α-ray excitation due to the 5d-4f transition. The relative scintillation light yield of 0.5 % Ce
³⁺
: CBO crystal showed about 30 %, while that of 0.5 % Pr
³⁺
: CBO crystal showed about 10 % compared with that of reference Li-glass (GS20) scintillator under
²⁵²
Cf neutron irradiation.