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The Nd-doped LaMgAl11O19 single crystals were synthesized by the floating zone method, and the photoluminescence and scintillation properties were evaluated. Under X-ray irradiation, several sharp emission peaks due to the 4f–4f transitions of Nd3+ were observed at 900, 1060, and 1340 nm in the near-infrared range, and the decay curves show the typical decay time for Nd3+. The samples show good afterglow properties comparable with practical X-ray scintillators. The 1% and 3% Nd-doped LaMgAl11O19 samples show a good linearity in the dynamic range from 6–60,000 mGy/h.

Tb-doped Mg 2 SiO 4 single crystals were grown by floating zone method, and photoluminescence (PL), scintillation, and thermally stimulated luminescence (TSL) properties were evaluated. In the PL and scintillation properties, Tb-doped Mg 2 SiO 4 single crystals showed emission peaks at 380, 420, 440, 460, 480, 495, 550, 590, and 630 nm, and the derived decay time constants were typical for the 4f-4f transitions of Tb 3+ ions. Regarding the dosimetric properties, TSL glow curves represented the main peaks at 50, 200, and 350 °C, and the TSL spectra exhibited the nine emission peaks due to Tb 3+ ions. Compared with a commercial TSL dosimeter (TORECK, MSO-S) equipped with powder-form Tb-doped Mg 2 SiO 4 , the integrated TSL intensity of the 0.4% Tb-doped single crystal was higher than that of MSO-S element in the dose range from 0.01 to 100 mGy air .

Mn-doped MgAl 2 O 4 single crystals were synthesized by the floating zone method equipped with four xenon arc lamps, and photoluminescence (PL), scintillation, and dosimetric properties were investigated. In PL and scintillation spectra, Mn-doped crystals showed an emission peak at 520 nm. The luminescence was ascribed to the d–d transition of Mn 2+ ion judging from the emission wavelength and decay time constants. In addition, Mn-doped crystals showed thermally and optically stimulated luminescence (TSL and OSL) with the emission peak at 520 nm, which was also considered to be due to the d–d transition of Mn 2+ ion. In both TSL and OSL dose–response functions, the 0.1% Mn-doped crystal showed linearly response from 0.01 to 1000 mGy.

We synthesized the Nd-doped Bi 4 Ge 3 O 12 (BGO) single crystals with different concentrations of Nd (0.1, 0.5, and 1%) by the floating zone method and evaluated the photoluminescence (PL) and scintillation properties. In both the PL and scintillation spectra, intrinsic luminescence of BGO was observed at 400–600 nm. In addition, emission peaks due to the 4f–4f transitions of Nd 3+ were observed in the near-infrared range. The 0.5% Nd-doped sample indicated the highest quantum yield of 42.9% among the samples. All the samples showed good linearity between X-ray exposure dose rate and the emission intensity in the NIR range. The lowest detectable dose rates were 0.06 Gy/h in the 0.1 and 1% Nd-doped BGO samples, and that of the 0.5% Nd-doped BGO sample was 0.01 Gy/h.

Undoped, 0.5, 1.0, and 2.0% Nd-doped Bi4Si3O12 (BSO) crystals were synthesized by the floating zone method. Regarding photoluminescence (PL) properties, all samples had emission peaks due to the 6p–6s transitions of Bi3+ ions. In addition, the Nd-doped samples had emission peaks due to the 4f–4f transitions of Nd3+ ions as well. The PL quantum yield of the 0.5, 1.0, and 2.0% Nd-doped samples in the near-infrared range were 67.9, 73.0, and 56.6%, respectively. Regarding X-ray-induced scintillation properties, all samples showed emission properties similar to PL. Afterglow levels at 20 ms after X-ray irradiation of the undoped, 0.5, 1.0, and 2.0% Nd-doped samples were 192.3, 205.9, 228.2, and 315.4 ppm, respectively. Dose rate response functions had good linearity from 0.006 to 60 Gy/h for the 1.0% Nd-doped BSO sample and from 0.03 to 60 Gy/h for the other samples.

ZnO translucent ceramics were synthesized by spark plasma sintering. To improve photoluminescence (PL) and scintillation properties caused by mainly oxygen vacancies in addition to some kinds of other defects, the synthesized samples were annealed at the temperature range from 600 to 800 °C in steps of 50 °C in the air. All the ZnO samples showed PL and scintillation at around 500 nm with the decay time constants of several microseconds order. After the annealing, the absorption due to oxygen vacancies was decreased, and PL quantum yields ( QY s) and scintillation light yields ( LY s) were improved in comparison with the as-prepared sample. Among all the samples, the ZnO translucent ceramic annealed at 750 °C showed the highest PL QY (25.1%) and LY s (44,200 ph/5.5 MeV-α and 30,500 ph/MeV).

Undoped and Tm-doped Ca 3 TaGa 3 Si 2 O 14 (CTGS) single crystals were synthesized by the floating-zone method, and their photoluminescence (PL) and scintillation properties were investigated. The Tm-doped samples showed PL and scintillation due to 4 f –4 f transitions of Tm 3+ . The PL quantum yields of the 0.1, 0.5, 1, and 2% Tm-doped CTGS samples were, respectively, 4.2, 28.2, 27.6, and 8.3% when excited at 360 nm. The afterglow levels at 20 ms after X-ray irradiation of all the samples were 10–83 ppm. The 0.1, 0.5, and 1% Tm-doped CTGS samples, respectively, showed the light yields of 1300, 1800, and 1500 photons/MeV under γ-ray irradiation.

Eulytite-type Ba3RE(PO4)3 (RE = Y, La, and Lu) single crystals were synthesized by the floating zone method, and their scintillation properties were investigated. The powder X-ray diffraction measurement revealed that the single phase of Ba3RE(PO4)3 samples were successfully synthesized. The samples exhibited a luminescence peak due to self-trapped exciton at around 400 nm under vacuum ultraviolet and X-ray irradiation. The X-ray-induced scintillation decay time constants of the samples were several microseconds at room temperature. In the 241Am α-ray irradiated pulse height spectra, all the samples showed a clear full energy peak, and the absolute light yields of the Ba3Y(PO4)3, Ba3La(PO4)3, and Ba3Lu(PO4)3 single crystals were estimated to be 960, 1160, and 1220 ph/5.5 MeV-α, with a typical error of ±10%, respectively. The scintillation light yields of the Ba3RE(PO4)3 have been quantitatively clarified for the first time.

Dy-doped Ba 3 Y(PO 4 ) 3 single crystals were grown by the floating zone (FZ) method, and the photoluminescence (PL) and thermally stimulated luminescence (TSL) properties were evaluated. The highest PL quantum yield value was obtained from the 5% Dy-doped sample. The Dy-doped sample displayed PL emission peaks at 480, 580, 670, and 760 nm when excitation wavelengths were 325, 350, and 385 nm. The peaks were caused by the 4f–4f transitions of Dy 3+ . The Dy-doped samples also represented TSL peaks due to the 4f–4f transitions of Dy 3+ when they were heated at 65 and 80 °C. The 1% Dy-doped sample showed the highest TSL intensity, and the TSL signal was detectable from 0.01 mGy.

A glass phosphor is an attractive material for applications in radiation detections because of its high workability and availability with a wide range of chemical compositions. Recently, X-ray-induced luminescence of glasses containing various luminescent activators are actively investigated worldwide. In applications as phosphor, tailoring valence state of activators, which can take multiple valence states in glass, is very important. In this research, we studied effects of glass melting atmosphere on the valence state of copper-activator ion in alkaline aluminophosphate glasses and the radiation-induced luminescence characteristics. Optical absorption and X-ray absorption near edge structure spectra of Cu-doped glasses showed that the glass fused in Ar atmosphere contains higher concentration of Cu + than those prepared in air. In addition, the presence of Cu + enhances the photoluminescence (PL) quantum yield and PL kinetic constant. Furthermore, the increase of Cu + concentration resulted an improvement of the X-ray-induced scintillation and thermally-stimulated luminescence intensity.