Keiichiro Saeki

Comparative study of scintillation properties of Cs2HfCl6 and Cs2ZrCl6

The photoluminescence and scintillation properties of Cs2HfCl6 and Cs2ZrCl6 crystals were investigated. Two emission bands in the photoluminescence spectra were observed at 375 and 435 nm for the Cs2HfCl6 crystal and at 440 and 479 nm for the Cs2ZrCl6 crystal. Similar spectra were observed for radioluminescence. The decay time constants were found to be about 2.2 and 8.4 µs for Cs2HfCl6 and 1.5 and 7.5 µs for Cs2ZrCl6. The scintillation light yields were estimated to be 27,500 and 25,100 photons/MeV for Cs2HfCl6 and Cs2ZrCl6, respectively.

Thallium magnesium chloride: A high light yield, large effective atomic number, intrinsically activated crystalline scintillator for X-ray and gamma-ray detection

We report the luminescence and the scintillation properties of a newly developed thallium magnesium chloride (TlMgCl3) crystal. The crystal sample can be easily fabricated from the melt using the Bridgman method. The photoluminescence band appeared near the wavelength of 405 nm under excitation at 230 nm. An X-ray-induced scintillation spectrum showed an intense emission band near the wavelength of 405 nm. The decay time constant was estimated to be approximately 60 ns (~25%) and 350 ns (~75%) using a bi-exponential fitting. The scintillation light yield reached 46,000 photons/MeV with an energy resolution of 5% at 662 keV.

Luminescence and scintillation properties of Rb2HfCl6 crystals

We developed a scintillator based on a Rb2HfCl6 crystal as a ternary halide crystal with intrinsic luminescence. In the photoluminescence spectra, two emission bands are observed at 383 and 434 nm. The 434 nm emission band for Rb2HfCl6 may be attributed to [HfCl6]2− complex ion or [ZrCl6]2− impurity, since the Rb2HfCl6 contained Zr as impurity at 0.62 mol %. The radioluminescence band is observed at 420 nm and can be attributed to the same origin as the photoluminescence band at 434 nm. The scintillation decay-time constants were 0.84 and 5.4 µs. The light yield was estimated to be 24,100 photons/MeV.

Photoluminescence and radiation response properties of Ce3+-doped CsCaCl3 crystalline scintillator

In this paper, we report on the photoluminescence and scintillation properties of a newly developed CsCaCl3:Ce (0.5 mol%) crystalline scintillator grown by the vertical Bridgman method. The fluorescence quantum efficiency for the Ce3+ characteristic emission bands centered at around 350–400 nm was 76% under excitation at 330 nm light. The photoluminescence decay time of the Ce3+ was approximately 32 ns. When x-ray excited the crystal, intense emission bands were observed at 350–400 nm, and could be attributed to the Ce3+ emission. The scintillation light yield of the developed crystal was ~7600 ph MeV−1 compared to a NaI:Tl commercial scintillator, and the principal scintillation decay time was approximately 340 ns plus two fast components of around 1.6 ns and 45 ns.