  Scintillation characteristics of undoped and Cu+-doped lithium tetraborate
Li2B4O7 (LTB) were studied including optical transmittance, photoluminescence,
radioluminescence for X- and gamma-rays, alpha/gamma ratio, and decay kinetics.
The total time-integrated LYs in undoped and Cu+-doped LTB for X-rays are ~600
and ~760 ph/MeV (photons/MeV), respectively. The decay kinetics in undoped and
Cu+-doped LTB are similar to each other. Typical decay spectra for pulsed
X-rays can be fitted with four exponentials: for fast (t1~0.8 ns, t2~25-50 ns),
medium (t3~300-400 ns), and slow (t4~20-30 ms) components. The slow component
occupies about 60% of the total LY, while the fast ones less than 10%. The
10-90% rise time was 163 ps. The alpha/gamma ratio was 0.18 for external 241Am
alpha-rays. The obtained increase in LY due to Cu+ doping remains modest. The
Cu+-induced emission contains both fast and slow components, requiring further
studies of the emission mechanism to explain the fast component.
