Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Dy3+-doped CaYAlO4 single crystals were fabricated by the floating zone method to investigate their optical, optically stimulated luminescence (OSL), and thermally stimulated luminescence (TSL) properties. Under excitation at 320–390 nm, emission bands due to Dy3+ were observed at 480 and 580 nm. In both the OSL and TSL, the 3% Dy-doped sample showed the highest luminescence intensity. In addition, the lowest detection limit of the 3% Dy-doped sample was 0.1 mGy in TSL, which was comparable with those of some commercially available dosimeters.

DOI： 10.1016/j.radphyschem.2024.111538

Language：English   Publishing type：Research paper (scientific journal)  

Optically-stimulated luminescence (OSL) and thermoluminescence (TL) properties of RbI:Eu single crystals synthesized by the vertical Bridgman-Stockberger method were evaluated. OSL peak at 430 nm due to 4f65d1-4f7 transition of Eu2+ was observed under stimulation at 750 nm. The 0.5% Eu-doped sample exhibited the highest OSL intensity among all the sample, and the detection limit was 1 mGy. TL glow peaks at ∼100 and ∼200 °C were observed and were ascribed to Fz-center (F-center near Eu2+-cation vacancy dipole) and F-center, respectively. The 0.5% Eu-doped sample showed the highest TL intensity among all the sample, and the detection limit was 0.01 mGy.

DOI： 10.1016/j.radmeas.2024.107102

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

We prepared Ca2BO3Cl with different concentrations (0.1 %, 0.5 %, and 1.0 %) of Eu2O3 for radiation dosimetry. Sharp photoluminescence peaks derived from 4f → 4f transition of Eu3+ appeared at 575, 590, 610, and 645 nm. On the other hand, the Eu2O3-doped Ca2BO3Cl exhibited a broad scintillation peak at around 600 nm due to 5d → 4f transition of Eu2+, and sharp peaks at approximately 590 and 610 nm derived from 4f → 4f transition of Eu3+. Furthermore, a major thermally-stimulated luminescence glow peak was detected at 250 °C, and a linear response in the range of 1–3000 mGy was observed from the Eu2O3-doped Ca2BO3Cl.

DOI： 10.1016/j.nimb.2023.165227

Publishing type：Research paper (scientific journal)  

Antimony based organic–inorganic hybrid compounds (Ph4P)2SbCl5 (Ph4P: tetraphenylphosphonium) and (DTA)2SbCl5 (DTA: dodecyltrimethylammonium) with a zero-dimensional structure were fabricated, and the optical and scintillation characteristics were evaluated. A broadband photoluminescence possibly due to self-trapped exciton (STE) emission appeared at 692 nm for (Ph4P)2SbCl5 and 630 nm for (DTA)2SbCl5 under 370 nm excitation light. The quantum yields were 98 % for (Ph4P)2SbCl5 and 97 % for (DTA)2SbCl5. Under X-ray, the broad emission peak was also detected at 670 nm for (Ph4P)2SbCl5 and at 615 nm for (DTA)2SbCl5. Furthermore, scintillation decay time constants were 4.9 μs for (Ph4P)2SbCl5 and 5.0 μs for (DTA)2SbCl5. Moreover, the scintillation light yield of (Ph4P)2SbCl5 was estimated to be about 12,000 photons/MeV, whereas the light of (DTA)2SbCl5 could not be determined. In addition, afterglow levels were 56 ppm for (Ph4P)2SbCl5 and 130 ppm for (DTA)2SbCl5.

DOI： 10.1016/j.radphyschem.2023.111399

Publishing type：Research paper (scientific journal)  

We report on the luminescence properties of CaF2 transparent ceramics having various concentrations of CeF3 (0.1 %, 0.5 %, and 1 %). Scintillation emissions centered at approximately 318, 345, and 386 nm derived from the 5d→4f transition of Ce3+ were detected, and scintillation light yields were determined to be 8600 photons/MeV (0.1 % CeF3), 1930 photons/MeV (0.5 % CeF3), and 1850 photons/MeV (1 % CeF3) under gamma-ray irradiation from 241Am. The Ce-doped CaF2 transparent ceramics showed thermally stimulated luminescence (TSL) with a broad glow peak at around 115–145 °C, and their dose response curves were determined over a broad dose range (0.01–3 mGy). Moreover, optically stimulated luminescence (OSL) exponential decay curves were obtained under 500 nm stimulation light, and dose response curves were obtained in the dose range of 0.1–100 mGy. The minimum detectable dose was estimated to be 0.1 mGy. A direct correlation between scintillation light yields under gamma-ray irradiation and TSL/OSL intensities was demonstrated.

DOI： 10.1016/j.materresbull.2023.112609

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Undoped and Ce-doped Tb4O7–Al2O3 glasses without glass network-former oxides were synthesized by the containerless method. The X-ray diffraction measurement indicated that the synthesized glass samples were amorphous. In diffuse transmission spectra, the undoped sample showed absorption due to Tb4+, and the reduction of Tb4+ to Tb3+ was observed in Ce-doped samples. In X-ray-induced scintillation spectra, the Ce-doped samples showed luminescence due to the 4f-4f transitions of Tb3+. This result indicated that CeCl3 acted as a reducer and enhanced the luminescence due to Tb3+. In addition, the Ce-doped samples suppressed the thermally stimulated luminescence glow peaks at the low-temperature region.

DOI： 10.18494/SAM4751

Publishing type：Research paper (scientific journal)  

0.1, 0.5, 1.0, and 5.0 % Eu-doped YVO4 single crystals were fabricated to assess photoluminescence (PL) and scintillation properties. The powder X-ray diffraction patterns of all the fabricated samples were the same as that of reference, and a single-phase structure of YVO4 was observed. The emission peaks owing to the 4f-4f transitions of Eu3+ ions were observed at 590, 605, 615, 620, and 695 nm in PL and scintillation spectra. Based on the pulse height spectra, Eu-doped samples had the light yield of 28,000 (0.1 % Eu), 33,000 (0.5 % Eu), 42,000 (1.0 % Eu), and 37,000 (5.0 % Eu) photons/MeV. In afterglow profiles, the afterglow level of 0.1, 0.5, 1.0, and 5.0 % Eu-doped samples was 58.1, 61.1, 49.1, and 35.6 ppm.

DOI： 10.1016/j.jlumin.2023.120327

Publishing type：Research paper (scientific journal)  

Tb-doped CaGdAlO4 crystals were investigated and showed photoluminescence peaks due to Tb3+. Likewise, multiple emission peaks derived from Tb3+ were detected in the optically stimulated luminescence. According to the thermally stimulated luminescence dose response, the detection limit was 1 µGy which was superior to several commercial dosimeters.

DOI： 10.1016/j.nimb.2023.165182

Publishing type：Research paper (scientific journal)  

Optical and scintillation properties of 50AEO-50SiO2-1SnO (AE = Mg, Ca, Sr, Ba) glasses were investigated. In photoluminescence (PL) and scintillation, the glasses showed a luminescence peak around 400 nm which was attributed to the T1-S0 transitions of Sn2+. The afterglow levels of the AE = Mg and Ba glasses were better than that of a commercial Tl-doped CsI scintillator. The light yields of the glasses were quantitatively acquired and the AE = Ba glass showed the highest light yield of 63 ph/5.5 MeV-α of among the glasses.

DOI： 10.1016/j.nimb.2023.165208

Language：English   Publishing type：Research paper (scientific journal)  

Undoped and Tb-doped single crystals of Sr3Y(PO4)3 were synthesized by the floating zone method, and the dosimetric properties of the obtained single crystals were investigated. The undoped crystal displayed a luminescence peak at 360 nm due to self-trapped excitons in both thermally and optically stimulated luminescence (TSL and OSL) spectra. The Tb-doped crystals showed luminescence peaks originating from 4f-4f transitions of Tb3+ in both TSL and OSL spectra. The 1% Tb-doped sample had the highest TSL and OSL intensities. The lower detection limits of TSL and OSL signals of the 1% Tb-doped sample were 0.01 and 0.1 mGy, respectively.

DOI： 10.18494/SAM4757

Publishing type：Research paper (scientific journal)  

In this work, we prepared Ca2BO3Cl with various amounts (0.1%-1.0%) of Tm2O3 by conventional solid-state reaction and investigated the dosimeter properties. Scintillation peaks at 370, 455, 470, and 650 nm that were derived from the 4f→4f transition of Tm3+ appeared in the X-ray induced scintillation spectra, and the highest scintillation intensity was detected from the 0.5% Tm2O3-doped Ca2BO3Cl. Furthermore, the Tm2O3-doped Ca2BO3Cl exhibited a thermally-stimulated luminescence (TSL) with a main glow peak at 300 °C, and the fabricated Tm2O3-doped Ca2BO3Cl exhibited a linear response in the 0.1-1000 mGy range. In addition, the TSL spectra confirmed that a final luminescence process for the TSL was the 4f→4f transition of Tm3+. In addition to TSL, optically-stimulated luminescence that was attributable to the 4f→4f transition of Tm3+ was recorded under 520 nm light, and the lowest detectable limit was about 1 mGy.

DOI： 10.35848/1347-4065/acf4a5

Publishing type：Research paper (scientific journal)  

We fabricated hybrid composites, where various organic-inorganic layered perovskite-type compounds (C6H5C2H4NH3)2PbBr4, (C6H5CH2NH3)2PbBr4, and (C4H9NH3)2PbBr4 were incorporated into a nanoporous glass, and their photoluminescence and scintillation properties were investigated for fast scintillator applications. A photoluminescence peak derived from free excitons was observed at around 410 nm for all the samples. Furthermore, a sharp scintillation peak originating from excitons was detected from the hybrid composites with (C6H5C2H4NH3)2PbBr4 or (C6H5CH2NH3)2PbBr4, and the hybrid composite with (C6H5C2H4NH3)2PbBr4 showed the highest scintillation intensity. In addition, afterglow levels of the fabricated hybrid composites were 430-620 ppm, and the values were higher than that of a (C6H5C2H4NH3)2PbBr4 single crystal.

DOI： 10.35848/1347-4065/acf4a8

Publishing type：Research paper (scientific journal)  

Y2SiO5 (YSO) single crystals with various Ce concentrations were fabricated and their photoluminescence (PL) and optically stimulated luminescence (OSL) properties analyzed. From the evaluation of PL properties, there was an emission band centered at 420 nm in Ce:YSO samples. The observed emission originated from the 5d-4f transitions of Ce3+ ions. In OSL properties, OSL spectra under stimulation at 520 nm exhibited emission peaks at 420 nm, and the emission origin was also the 5d-4f transitions of Ce3+ ions. The OSL dose response functions had a lower detection limit of 1 mGy for the 0.5 and 1.0% Ce:YSO samples, and 10 mGy for the 0.1 and 2.0% Ce: YSO samples. The OSL intensity of the 1.0% Ce:YSO sample was approximately 69.3% after 24 h from X-ray irradiation compared to immediately after X-ray irradiation.

DOI： 10.35848/1347-4065/acf4a7

Publishing type：Research paper (scientific journal)  

We fabricated (Ph4P)2ZnCl4 and (Ph4P)2ZnBr4 crystals (Ph4P: tetraphenylphosphonium) with zero-dimensional structures via solvent evaporation and evaluated their optical and scintillation properties. Fluorescence and phosphorescence peaks derived from Ph4P+ cations appeared at 345 and 510 nm, respectively, for both crystals, while an emission originating from self-trapped excitons was also detected for (Ph4P)2ZnBr4. In the scintillation spectra, both samples exhibited a phosphorescence peak, while a weak fluorescence peak was also observed for (Ph4P)2ZnCl4. In addition, the scintillation light yield (LY) was determined by pulse-height spectra with 1 μs shaping time. A pulse-height peak was observed from (Ph4P)2ZnCl4, and the scintillation LY was about 670 photons/5.5 MeV-α, which was higher than that of a ZnO single crystal.

DOI： 10.35848/1347-4065/acfa09

Publishing type：Research paper (scientific journal)  

Dy-doped Ba3Y(PO4)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 Dy3+. The Dy-doped samples also represented TSL peaks due to the 4f–4f transitions of Dy3+ 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.

DOI： 10.1007/s10854-024-11995-w

Publishing type：Research paper (scientific journal)  

Non-doped and Ce-doped LiAl5O8 single crystals were prepared to investigate their properties as a neutron detector. The 1% Ce-doped LiAl5O8 indicated photoluminescence and scintillation peaks at around 340, 430, and 700 nm. From the viewpoint of the results of decay profiles, the peaks at 340 and 430 nm are due to 5d-4f transition of Ce3+, and the peak at 700 nm is caused by Fe3+. The clear thermal neutron peaks were detected regardless of Ce concentration. The LY of the non-doped, 0.1, 0.3, and 1% Ce-doped LiAl5O8 was estimated to be 390, 443, 446, and 468 ph/n.

DOI： 10.1016/j.nimb.2023.165168

Publishing type：Research paper (scientific journal)  

Undoped and Tb-doped Ba3Y(PO4)3 single crystals were synthesized by the floating zone method. Photoluminescence (PL), scintillation, and dosimetric properties of the obtained single crystals were measured. The highest PL quantum yield value was obtained from the 15% Tb-doped crystal. In X-ray-induced scintillation spectra, the undoped crystal showed an emission peak due to self-trapped exciton at 400 nm. Tb-doped crystals showed emission peaks in the range of 375–620 nm, originated from 4f-4f transitions of Tb3+. In addition, the undoped and Tb-doped crystals showed luminescence peaks in similar locations to the scintillation spectra in thermally and optically stimulated luminescence (TSL and OSL). In TSL dose response functions, the 1% Tb-doped sample exhibited the highest TSL intensity, and the TSL signal was detectable from 0.01 mGy. In OSL dose response functions, the 5% Tb-doped sample exhibited the highest OSL intensity, and the OSL signal was observed from 0.1 mGy.

DOI： 10.1016/j.optmat.2023.114665

Publishing type：Research paper (scientific journal)  

We prepared organic–inorganic layered perovskite-type compounds having a linear alkyl diamine (NH3CnH2nNH3)PbCl4 (n = 6: (1, 6-DHX)PbCl4, n = 7: (1,7-DHP)PbCl4, n = 8: (1,8-DIO)PbCl4, n = 9: (1,9-DIN)PbCl4, n = 10: (1,10-DID)PbCl4, n = 11: (1,11-DIU)PbCl4) and investigated their photoluminescence and scintillation characteristics. A broad band peak that should be attributed to self-trapped excitons (STEs) were observed at 555 nm ((1,6-DHX)PbCl4), 520 nm ((1,7-DHP)PbCl4), 525 nm ((1,8-DIO)PbCl4), 525 nm ((1,9-DIN)PbCl4), 550 nm ((1,10-DID)PbCl4), and 530 nm ((1,11-DIU)PbCl4) in scintillation. Also, they showed a scintillation decay time of 2.2 ns ((1,6-DHX)PbCl4), 3.0 ns ((1,7-DHP)PbCl4), 2.8 ns ((1,8-DIO)PbCl4), 5.6 ns ((1,9-DIN)PbCl4), 3.5 ns ((1,10-DID)PbCl4), and 4.7 ns ((1,11-DIU)PbCl4) due to the STE recombination. Further, the scintillation light yield of the (1,9-DIN)PbCl4 crystal was the highest (1,200 photons/5.5 MeV-α), and its value was higher than that of an undoped zinc oxide crystal.

DOI： 10.1007/s10854-024-11935-8

Publishing type：Research paper (scientific journal)  

Undoped and Tb-doped Ba3Gd(PO4)3 single crystals were synthesized by the floating zone method. Photoluminescence (PL), scintillation, and thermally stimulated luminescence (TSL) properties of the obtained single crystals were evaluated. The highest PL quantum yield value was obtained from the 5% Tb-doped single crystal. In X-ray-induced scintillation and TSL spectra, the undoped sample represented an emission peak originating from the 4f-4f transition of Gd3+ at 310 nm. The Tb-doped samples represented emission peaks originating from the 4f-4f transitions of Tb3+ and Gd3+ in the range of 310-620 nm. In TSL dose response functions, the 1% Tb-doped sample showed the highest TSL intensity, and the lower detection limit was 0.01 mGy.

DOI： 10.35848/1347-4065/ad0a46

Publishing type：Research paper (scientific journal)  

To develop glass scintillators, Eu2O3-doped tellurite glasses (TeO2–Nb2O5–SrO–Eu2O3) (TNbSrEu) were prepared, and their luminescence characteristics were investigated. Several photoluminescence peaks at about 578, 592, 613, 652, and 701 nm were observed when excited by 530 nm excitation light. They originated from 4f→4f transition of Eu3+. Their photoluminescence decay times under 530 nm excitation light were approximately 0.7 ms, which was a typical time of 4f→4f transition of Eu3+. Further, some scintillation peaks originating from 4f→4f transition of Eu3+ were detected at 577, 593, 613, and 652 nm, and scintillation decay times were in the time region of 0.21–0.35 ms. Furthermore, the afterglow levels were from 560 ppm to 317 ppm, showing a decreasing trend in levels with increasing Eu2O3 concentration.

DOI： 10.1016/j.optmat.2023.114574

Publishing type：Research paper (scientific journal)  

We fabricated undoped and 0.5, 1.0, 2.0, and 3.0% Eu-doped Al4SiO8 single crystals by the floating zone method and analyzed their photoluminescence (PL) and thermally stimulated luminescence (TSL) properties. In PL properties, the undoped sample exhibited an emission band at 460 nm under excitation wavelength at 260 nm. The Eu-doped samples showed an emission band at 410 nm attributed to the 5d-4f transitions of Eu2+ ions. In TSL properties, the undoped sample exhibited TSL glow peaks at 280 and 390 °C, while the Eu-doped samples showed the ones at 230 and 370 °C. The TSL spectra of the Eu-doped samples under heating at 230 °C had an emission band due to the 5d-4f transitions of Eu2+ ions. TSL dose response functions showed a lower detection limit of 10 mGy for the undoped sample, 10 μGy for the 0.5% Eu-doped sample, and 1 μGy for the 1.0, 2.0, and 3.0% Eu-doped samples. The TSL intensity of the 2.0% Eu-doped sample was approximately 72.6% after 11 days from X-ray irradiation compared to immediately after X-ray irradiation.

DOI： 10.1016/j.optmat.2023.114425

Publishing type：Research paper (scientific journal)  

Tb-doped CaYAlO4 crystals were grown by the floating zone method, and then the samples were annealed under reduction condition to remove extra oxygen in CaYAlO4. Under excitation at 250 nm, multiple photoluminescence peaks due to Tb3+ were observed at 385–620 nm in all the samples. In thermally stimulated luminescence, the sample annealed for 12 h showed the highest luminescence intensity among the Tb-doped samples. The luminescence intensity of the annealed samples increased by two digits than that of the unannealed sample, and the lowest measurable dose of the annealed samples was 0.01 mGy.

DOI： 10.1007/s10854-023-11442-2

Publishing type：Research paper (scientific journal)  

We synthesized the Ti-doped MgGa2O4 single crystals as a novel radiation detection material. XRD patterns indicated the synthesized crystals were single phase of MgGa2O4. Diffuse transmission spectra revealed that Ti was doped into octahedral Ga3+ site as Ti4+ and tetrahedral Mg2+ site as Ti3+. The 0.1% Ti-doped crystal showed the highest photoluminescence quantum yield among the crystals. The 0.1% Ti-doped crystal also performed the best in view point of scintillation light yield and lowest measurable dose in thermally stimulated luminescence (TSL). The scintillation light yield and lowest measurable dose in TSL of the 0.1% Ti-doped crystal were 5208 ph/5.5 MeV-α and 0.1 mGy, respectively.

DOI： 10.1016/j.ijleo.2023.171135

Publishing type：Research paper (scientific journal)  

DOI： 10.35848/1347-4065/acf4a8

Publishing type：Research paper (scientific journal)  

We evaluated photoluminescence and radiation response properties of organic–inorganic perovskite-type compounds with various hydroxyl alkyl amines or alkyl ether amines (HOCnH2nNH3)2PbCl4 (n = 2: C2–OH, n = 3: C3–OH, n = 4: C4–OH), (CH3CH2OCnH2nNH3)2PbCl4 (n = 2: 2-Ethoxy, n = 3: 3-Ethoxy), and (CH3C2H4OC3H6NH3)2PbCl4 (3-Butoxy). A clear broadband emission peak attributed to self-trapped excitons (STEs) was detected from the C2–OH, C3–OH, and 2-Ethoxy crystals under 310 nm excitation light. Additionally, they showed a fast decay time of 3.5 ns (C2–OH), 5.5 ns (C3–OH), and 3.0 ns (2-Ethoxy), which was ascribed to the recombination of STEs. In the scintillation spectra, the C2–OH, C3–OH, and 2-Ethoxy crystals exhibited a broad emission originating from the recombination to STEs. Furthermore, they exhibited a fast scintillation decay time of 2.2 ns (C2–OH), 3.5 ns (C3–OH), and 1.1 ns (2-Ethoxy) due to the recombination of STEs. Moreover, the light yield of the C3–OH crystal under alpha-ray was the highest, and the yield was estimated to be 1100 photons/5.5 MeV-α, which was higher than that of a ZnO single crystal.

DOI： 10.1016/j.radphyschem.2023.110981

Publishing type：Research paper (scientific journal)  

Recently, glasses have gained great interest for use as scintillators owing to lots of industrial benefits such as ease of producing customizable shapes and low production cost. Herein, the Er3+-activated BaO-Nb2O5-TeO2 glasses were fabricated for the development of NIR glass scintillators. The Er3+-activated BaO-Nb2O5-TeO2 glasses exhibited efficient photoluminescence and scintillation that originated from the 4f→4f transition of Er3+. Their quantum yields in photoluminescence were 80% (0.1%Er2O3), 81% (0.5%Er2O3), and 61% (1.0%Er2O3). Further, an almost linear correlation between an X-ray dose rate and NIR scintillation intensity was observed in the 0.5-5000 mGy h−1 dose rate range. Interestingly, the lowest detectable dose rate limit (0.5 mGy h−1) was lower than that of Er-doped Bi4Ge3O12 and Nd-doped GdVO4 single crystals. Further, afterglow levels of the non-doped and Er3+-activated BaO-Nb2O5-TeO2 glasses were about 600 ppm. The observed NIR scintillation properties indicated that the Er3+-activated tellurite glasses should be promising compounds for NIR-emitting scintillators.

DOI： 10.35848/1347-4065/ace013

Publishing type：Research paper (scientific journal)  

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.

DOI： 10.3390/ma16134502

Publishing type：Research paper (scientific journal)  

We report on the fabrication of Tb-doped barium fluoride translucent ceramics, and their scintillation and dosimetric characteristics. The Tb-doped barium fluoride ceramics were fabricated by spark plasma sintering. Scintillation derived from the 4f→4f transitions of Tb3+ under X-rays was observed from the Tb-doped barium fluoride ceramics. Their decay times under X-rays were about 10 ms. Further, thermally-stimulated luminescence originating from the transitions was detected, and their dose responses were observed in the range of 0.1–100 mGy. Moreover, the Tb-doped barium fluoride ceramics exhibited optically-stimulated luminescence (OSL), and three exponential decay components were detected in the OSL decay curves.

DOI： 10.1016/j.optmat.2023.113948

Publishing type：Research paper (scientific journal)  

Tellurite glass (TeG) and its glass-ceramics (TeGC435 and TeGC455), with a composition of 10Eu2O3–10BaO–80TeO2, were prepared and their luminescence properties were evaluated. TeG was prepared via the melt quenching technique, while TeGC435 and TeGC455 were fabricated by heat treating TeG at 435 and 455 °C, respectively, for 5 h each. The Eu2Te6O15 crystal phase was formed in TeGC435 and TeGC455. Both the glass and glass-ceramics showed sharp photoluminescence and scintillation peaks, attributed to the 4f→4f transitions of Eu3+. The highest quantum yield was obtained for TeG, whereas the highest integrated scintillation intensity was obtained for TeGC455. The scintillation intensity of TeGC455 was approximately 10% of that of the Bi4Ge3O12 single crystal. Furthermore, typical decay times derived from the 4f→4f transitions were obtained for TeG, TeGC435, and TeGC455 during photoluminescence and scintillation.

DOI： 10.1016/j.ceramint.2023.01.183

Publishing type：Research paper (scientific journal)  

We report radio-photoluminescence (RPL) properties of Sm-doped Al4SiO8 single crystals as a new RPL material. The Sm-doped Al4SiO8 single crystals were synthesized by the floating zone method. In PL emission spectra, the emission peaks due to the 4f-4f transitions of Sm3+ ions and 2EJ–4A2 transitions of Cr3+ ions were observed before X-ray irradiation, and the ones due to the 4f-4f transitions of Sm2+ appeared as well as Sm3+ after X-ray irradiation. The RPL dose response functions showed linear response from 1 mGy to 10 Gy for the 2.0% Sm-doped sample and from 10 mGy to 10 Gy for the others. Sm2+ ions of the new emission center completely disappeared by heat treatment at 500 °C for 10 min.

DOI： 10.1016/j.jlumin.2023.119698

Publishing type：Research paper (scientific journal)  

BaF2 translucent ceramics with various amounts of TmF3 (0.01%, 0.1% and 1%) were fabricated, and their scintillation and thermally-stimulated luminescence (TSL) characteristics were evaluated. The Tm-doped BaF2 translucent ceramics showed a broad luminescence peak at approximately 300 nm originating from self-trapped excitons (STEs) while several sharp peaks derived from the 4f→4f transitions of Tm3+ were also detected from the 0.1% and 1% Tm-doped BaF2 translucent ceramics. Further, a TSL spectrum due to the 4f→4f transitions of Tm3+ was obtained at around 190 °C from the 1% Tm-doped BaF2 translucent ceramic while a weak broad peak due to STEs was observed at around 80 °C from the 0.01% Tm-doped BaF2 translucent ceramic. The 1% Tm-doped BaF2 translucent ceramic exhibited the strongest TSL glow peak intensity, and its linear TSL response was confirmed over a broad range, from 0.1 to 1000 mGy.

DOI： 10.1007/s10854-023-10343-8

Publishing type：Research paper (scientific journal)  

We synthesized the 0.5, 1.0, 2.0, and 3.0% Er-doped Bi4Si3O12 (BSO) single crystals and researched the photoluminescence (PL) and scintillation properties in visible-near infrared ranges. The X-ray diffraction analysis indicated that the synthesized samples had single-phase structure of BSO. In transmission spectra, all the samples had some absorption peaks owing to the 4f-4f transitions of Er3+ ions. In PL and scintillation properties, all the samples had the emission peaks due to the 6p-6s transitions of Bi3+ ions and the 4f-4f transitions of Er3+ ions. Afterglow levels at 20 ms after X-ray irradiation of the 0.5, 1.0, 2.0, and 3.0% Er-doped samples were 348.9, 587.9, 616.6, and 666.6 ppm, respectively. The light yields of the 0.5, 1.0, 2.0, and 3.0% Er-doped samples were 1600, 1200, 900, and 750 ± 10% ph/MeV, respectively. The dose rate response functions of all the samples showed the linear relationship between dose rate and scintillation intensity from 0.006 to 6 Gy h−1, and the 2.0% Er-doped sample had the highest intensity among the samples

DOI： 10.1149/2162-8777/acc7c7

Publishing type：Research paper (scientific journal)  

In this study, Mg1.995-xSiO4:xCe, 0.005Tb (x = 0 and 0.01) single crystals were synthesized by the floating zone method and their photoluminescence (PL) and dosimetric properties were evaluated. In the PL process, emission peaks due to the 4f-4f transitions of Tb3+ ions were observed in the x = 0 and 0.01 samples, and the emission peak due to the 5d-4f transitions of Ce3+ ions was detected in the x = 0.01 sample. In the thermally stimulated luminescence (TSL) process, only emission peaks due to the 4f-4f transitions of Tb3+ ions were observed in both samples, and the x = 0.01 sample had higher TSL intensity than the x = 0 sample. The x = 0.01 sample showed a lower detection limit of 0.01 mGy and a spatial resolution of 50.0 μm under X-ray irradiation.

DOI： 10.18494/SAM4143

Publishing type：Research paper (scientific journal)  

We synthesized 20Lu2O3-30Ga2O3-50SiO2 glasses doped with various concentrations of Sn using a floating zone furnace equipped with Xe arc lamps. The samples showed a luminescence band around 450 nm in both photoluminescence (PL) and scintillation spectra. The origin of the luminescence was ascribed to the T1-S0 transition of Sn2+ on the basis of the luminescence wavelength and PL decay time constant. The highest scintillation intensity and PL quantum yield were observed from the 1% Sn-doped sample. The afterglow level tended to decrease with increasing Sn doping, and the afterglow levels of the 1 and 3% Sn-doped samples were comparable to that of the conventional Tl-doped CsI scintillator. The optimal concentration of Sn for the glass was estimated to be 1%.

DOI： 10.18494/SAM4142

Publishing type：Research paper (scientific journal)  

We prepared (H3NC8H16NH3)PbBr4 (1-8DIO), (H3NC10H20NH3)PbBr4 (1-10DID), and (H3NC12H24NH3)PbBr4 (1-12DIDD) crystals, and evaluated the photoluminescence (PL) and scintillation characteristics. A luminescence peak derived from free excitons was detected at around 400 nm from the crystals in the PL spectra, and the quantum yields were 8% (1-8DIO), 13% (1-10DID), and 7% (1-12DIDD). Also, scintillation light yields were determined to be 5070 photons MeV-1 for the 1-8DIO crystal, 2400 photons MeV-1 for the 1-10DID crystal, and 830 photons MeV-1 for the 1-12DIDD crystal, and they had a fast scintillation decay time of 4.8 ns (1-8DIO), 6.8 ns (1-10DID), and 3.1 ns (1-12DIDD) owing to the free exciton emissions.

DOI： 10.35848/1347-4065/acbff5

Publishing type：Research paper (scientific journal)  

Organic-inorganic perovskite crystals (C6H5C n H2n NH3)2PbCl4 (n = 1: PMA, n = 2: PEA, n = 3: PPA, and n = 4: PBA) were prepared, and their scintillation characteristics were evaluated. A broad emission peak originating from self-trapped excitons (STE) was observed from all of the crystals when excited by 310 nm light. Further, the broad emission was also clearly observed from PMA, PEA, and PBA under X-ray. Moreover, the scintillation light yields under α-ray were calculated to be 1460 (PEA), 439 (PPA), and 120 (PBA) photons/5.5 MeV-α, and the light yield of PEA was higher than that of a ZnO single crystal. In addition, all of the crystals showed a fast decay-time attributable to STE under X-ray.

DOI： 10.35848/1347-4065/ac8f02

Publishing type：Research paper (scientific journal)  

Tb-doped SiO2 glasses were synthesized by the spark plasma sintering (SPS) method, and optical and thermally stimulated luminescence (TSL) properties were investigated. The diffuse transmittance spectra of the 0.01, 0.05, and 0.1% Tb-doped SiO2 samples included the absorption due to the 4f-5d transitions of Tb3+ ions. In photoluminescence properties, all the Tb-doped SiO2 samples showed several emission peaks due to the 4f-4f transitions of Tb3+ ions and oxygen deficiency vacancy (ODC). The TSL glow curves indicated the glow peak at 140 °C, and only the emission peaks attributed to the 4f-4f transition of Tb3+ ions were observed in TSL spectra of the 0.01, 0.05, and 0.1% Tb-doped SiO2 samples. The integrated TSL intensity of the 0.1% Tb-doped samples had a proportional relationship in the range of 0.01–1000 mGy. The TSL intensity of the 0.05% Tb-doped glass after 72 h from X-ray irradiation was about 69% with respect to the one immediately after X-ray irradiation. In addition, the 0.05% Tb-doped SiO2 glass could use the multiple time for TSL dosimetry.

DOI： 10.1016/j.radphyschem.2022.110515

Publishing type：Research paper (scientific journal)  

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.

DOI： 10.3390/ma15248784

Publishing type：Research paper (scientific journal)  

We synthesized the 0.1, 0.5, 1.0, and 1.5% Ce-doped mullite single crystals by the floating zone method and evaluated their photoluminescence (PL) and thermally stimulated luminescence (TSL) properties. The single-phase orthorhombic structure was confirmed in all the samples from powder X-ray diffraction patterns. The transmittance spectra of all the samples showed the absorption related to the 4f-5d transitions of Ce3+ ions and optical band gap of mullite. The Ce-doped mullite single crystals had the PL attributed to the 5d-4f transitions of Ce3+ ions. In TSL properties, TSL glow curves had the glow peaks at 250 and 370 °C, and TSL spectra heated at 250 and 370 °C had the peak at around 390 nm owing to the Ce3+ ions. TSL dose response functions showed linear response from 0.01 mGy to 10 Gy for the 1.0% Ce-doped mullite single crystal and from 0.1 mGy to 10 Gy for the 0.1, 0.5, and 1.5% Ce-doped ones. The 1.0% Ce-doped mullite single crystal could be used multiple times for dosimetry. In addition, the TSL intensity of the 1.0% Ce-doped mullite single crystal after 7 days from X-ray irradiation was about 82.4% from immediately one after X-ray irradiation.

DOI： 10.1016/j.apradiso.2022.110521

Publishing type：Research paper (scientific journal)  

Optical, scintillation, and dosimetric properties of the undoped and Tb-doped CaYAlO4 single crystals grown by the floating zone method were evaluated. Several photoluminescence (PL) emission peaks due to the 4f–4f transitions of Tb3+ ion were observed at 385–620 nm under excitation at 250 nm in Tb-doped CaYAlO4 samples. Under X-ray irradiation, scintillation peaks of the Tb-doped CaYAlO4 crystals were consistent with the PL emission peaks. In terms of a dosimetric property, the 0.1% Tb-doped crystal exhibited the highest thermally stimulated luminescence intensity and the widest linear responses in the range of 0.01–1000 mGy among the samples.

DOI： 10.1016/j.optmat.2022.113068

Publishing type：Research paper (scientific journal)  

We reported the photoluminescence (PL) and scintillation characteristics of various organic-inorganic perovskite-type compounds having a diamine: (H3NC5H10NH3)PbBr4 (1-5DIP), (H3NC6H12NH3)PbBr4 (1-6DIH), (H3NC10H20O2NH3)PbBr4 (BBE), and (H3NC10H20O3NH3)PbBr4 (DGBE). In the PL spectra, an emission peak derived from free excitons in the inorganic layer was detected at approximately 410 nm (1-5DIP) and 400 nm (1-6DIH, BBE, and DGBE). Quantum yields of the 1-5DIP, 1-6DIH, BBE and DGBE crystals were 0.2%, 6.0%, 4.0%, and 4.2%, respectively. A scintillation peak originating from exciton emissions appeared at around 430 nm (1-6DIH, BBE and DBE), and 440 nm (1-5DIP) under X-ray radiation. Further, their pulse height spectra were recorded under 241Am gamma-ray irradiation, and their scintillation light yields were 4400 photons MeV−1 (1-6DIH), 1400 photons MeV−1 (BBE), and 1700 photons MeV−1 (DGBE), whereas the yield of the 1-5DIP was not obtained.

DOI： 10.35848/1347-4065/ac943d

Publishing type：Research paper (scientific journal)  

Tb-doped MgGa2O4 single crystals (0.3, 1, 3, and 5%) were synthesized by the floating zone method. The synthesized crystals had a single phase of MgGa2O4 confirmed by X-ray diffraction and high transparency in the visible wavelength. Tb3+ acted as a luminescence center in both photoluminescence (PL) and thermally stimulated luminescence (TSL) processes. In the TSL dose response functions, the minimum detectable dose of the crystals was 0.01 mGy, which was comparable with some commercial dosimetric materials. In the X-ray imaging test taken based on TSL, the spatial resolution of the 1% Tb-doped crystal was estimated to be 8.90 LP/mm (56.2 μm).

DOI： 10.3390/cryst12111620

Publishing type：Research paper (scientific journal)  

The Tm-doped MgAl2O4 single crystals were synthesized by using Xe arc lamps-equipped floating zone furnace. The synthesized crystals exhibited luminescence due to the 4f-4f transitions of Tm3+ in photoluminescence (PL), scintillation, and thermally stimulated luminescence (TSL). In all of PL, scintillation, and TSL, the 0.5% Tm-doped crystal showed the highest luminescence intensity. In TSL dose response functions, the 0.5% Tm-doped crystal showed sensitivity from X-ray irradiation with 0.1 mGy. In addition, we measured linear energy transfer (LET) dependence on TSL glow curve of the crystal and X-ray imaging test taken by TSL. We revealed the spatial resolution of the crystal was 100 μm.

DOI： 10.1016/j.jlumin.2022.119247

Publishing type：Research paper (scientific journal)  

We synthesized Ca2BO3Cl with various amounts of MnCl2 to fabricate phosphors for radiation dosimetry. After the synthesis, we evaluated their scintillation, thermally-stimulated luminescence (TSL), and optically-stimulated luminescence (OSL) characteristics. A scintillation peak derived from the 4T1 → 6A1 transition of Mn2+ appeared at approximately 600 nm in the MnCl2-doped Ca2BO3Cl. Further, their decay time constants were approximately 0.13 ms that should be ascribed to the 4T1 → 6A1 transition. Moreover, the MnCl2-doped Ca2BO3Cl exhibited TSL glow peaks at approximately 85 °C, 170 °C, and 280 °C. The linear response of the 0.1% MnCl2-doped Ca2BO3Cl was confirmed in the X-ray dose range of 10-3000 mGy. In addition, a weak OSL peak derived from the 4T1 → 6A1 transition was detected at around 600 nm from the 0.1% and 0.5% MnCl2-doped Ca2BO3Cl.

DOI： 10.35848/1347-4065/ac9104

Publishing type：Research paper (scientific journal)  

1Eu2O3–3BaO–20Nb2O5–76TeO2 glass and the corresponding glass-ceramics were synthesized with the aim to investigate the effect of glass crystallization on the photoluminescence and scintillation characteristics. Glass ceramics containing mainly the Nb2Te4O13 crystalline phase were obtained by heat treatment of the glass at 540 °C for 1, 2, or 4 h. For the glass and glass ceramics, emission peaks originating from the 4f → 4f transitions of Eu3+ appeared under irradiation with 530 nm light or X-rays. Among the samples, the highest emission intensity in the photoluminescence and X-ray-induced scintillation spectra was obtained for the glass. Furthermore, typical photoluminescence and scintillation decay time constants originating from the 4f → 4f transitions of Eu3+ were obtained for the glass and glass ceramics. The afterglow level of the glass was comparable to that of the glass ceramics.

DOI： 10.1007/s10854-022-08861-y

Publishing type：Research paper (scientific journal)  

Eu2O3-doped tellurite glasses (15WO3–5Al2O3–80TeO2) were fabricated and their scintillation characteristics were investigated. Typical emissions originating from the 4f→4f transitions of Eu3+ were observed at 580, 592, 614, 653, and 702 nm when irradiated with visible light. The quantum yield of the Eu2O3-doped glass increased as the Eu2O3 concentration increased, and the 5.0% Eu2O3-doped glass exhibited the largest quantum yield of 76%. Further, scintillation originating from the 4f→4f transition of Eu3+ was also detected under X-ray irradiation, and the integrated scintillation intensity depended on the quantum yield. The afterglow levels of the glasses decreased with increasing the Eu2O3 concentration, and the level of the 5.0% Eu2O3-doped glass was 193 ppm, which was close to that of the Tl-doped CsI.

DOI： 10.1016/j.jlumin.2022.119003

Publishing type：Research paper (scientific journal)  

We have investigated photoluminescence (PL), scintillation, and dosimetric properties of the undoped and Tb-doped LiCaPO4 samples. The luminescence origin of the undoped and Tb-doped samples were ascribed to the self-trapped exciton (STE) and 4f-4f transitions of the Tb3+, respectively. In Thermally stimulated luminescence (TSL) glow curves, undoped samples showed main peak at 220 °C, and Tb-doped samples showed main peak at 130 °C. The Tb-doped samples demonstrated the more than 50 times higher TSL intensity than that of undoped one. In addition, the lowest measurable dose (LMD) of the Tb-doped samples were estimated to exceed 1 μGy.

DOI： 10.1016/j.radphyschem.2022.110180

Publishing type：Research paper (scientific journal)  

In this study, we grew the Dy-doped Mg2SiO4 single crystals by the floating zone method to investigate the photoluminescence (PL) and thermally stimulated luminescence (TSL) properties. All the Dy-doped Mg2SiO4 showed the emission peaks at 480, 580, and 670 nm in PL and TSL spectra, and these peak wavelengths were typical for the 4f-4f transitions of Dy3+ ions. In the TSL glow curves, all the samples had the glow peaks at 50 °C, 200 °C, 280 °C, and 380 °C. The TSL dose response function of the 1% Dy-doped Mg2SiO4 single crystal showed a good linearity across 1-10000 mGy.

DOI： 10.35848/1347-4065/ac5e91

Publishing type：Research paper (scientific journal)  

We have synthesized Dy-doped LiCaPO4 samples by the conventional solid-state reaction and evaluated photoluminescence (PL), scintillation, and dosimetric properties. The samples showed luminescence which was attributed to the 4f-4f transitions of Dy3+ by irradiation of UV and X-ray. The highest PL quantum yield (QY) of 59.2% was obtained from the 0.5% Dy-doped sample. The 0.5% Dy-doped sample exhibit the highest intensity in scintillation and thermally stimulated luminescence (TSL) as well. In TSL dose response function, the 0.5% Dy-doped LiCaPO4 showed the proportional relationship from 0.01 to 30 mGy under X-ray irradiation. The TSL intensity surpassed the commercial product.

DOI： 10.1016/j.ijleo.2022.169079

Publishing type：Research paper (scientific journal)  

Tb-doped Mg2SiO4 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 Mg2SiO4 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 Tb3+ 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 Tb3+ ions. Compared with a commercial TSL dosimeter (TORECK, MSO-S) equipped with powder-form Tb-doped Mg2SiO4, 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 mGyair.

DOI： 10.1007/s10854-022-08298-3

Publishing type：Research paper (scientific journal)  

Photoluminescence and thermally-stimulated luminescence (TSL) characteristics of BaCaBO3F doped with various amounts of Tm were evaluated. The Tm-doped BaCaBO3F showed an emission with a sharp peak around 460 nm originating from the 4f-4f transition of Tm3+ in photoluminescence and scintillation. Their photoluminescence and scintillation decay times for the Tm-doped BaCaBO3F were 0.68–0.73 and 1.28–1.55 ms, respectively. Furthermore, the TSL dynamic range of the glow peaks at 190 °C for the 0.5% Tm-doped BaCaBO3F was from 0.1 mGy to 1000 mGy. Furthermore, the TSL isothermal analysis of the Tm-doped BaCaBO3F suggested that at least 12 different activation energies related to TSL were confirmed.

DOI： 10.1016/j.optmat.2022.112222

Publishing type：Research paper (scientific journal)  

Eu2O3-doped 40K2O–20Ta2O5–40Ga2O3 gallate glasses were synthesized, and their radiation response characteristics were studied systematically. According to their photoluminescence spectra, they showed intense emissions with sharp peaks centered at around 580, 594, 613, 656, and 706 nm when irradiated by 380 nm light. The sharp peaks originate from the 4f-4f transitions of Eu3+. Moreover, these sharp peaks were also detected when excited by X-ray, and the 1.0% Eu2O3-doped gallate glasses showed the largest luminescence intensity under UV light and X-ray. Furthermore, the afterglow levels of the Eu2O3-doped 40K2O–20Ta2O5–40Ga2O3 gallate glasses were determined to be approximately 300 ppm. These levels are close to the levels of TI-doped CsI single crystals.

DOI： 10.1016/j.ceramint.2021.12.130

Publishing type：Research paper (scientific journal)  

We prepared 25Li2O-10MgO-65SiO2 glasses doped with various concentrations of Ce by the melt-quenching method and systematically evaluated their photoluminescence (PL) and dosimetric properties. X-ray diffraction patterns showed that the prepared samples were in an amorphous state. The PL spectra and decay curves of the Ce-doped glasses confirmed the PL emission peak due to the 5d-4f transitions of Ce3+ ions. The PL quantum yields of the 0.3, 1, 3, 5, and 10% Ce-doped glasses were 17.5, 31.0, 36.6, 27.2, and 26.3%, respectively. Regarding dosimetric properties, the Ce-doped glasses showed thermally stimulated luminescence (TSL) at 100, 300, and 400°C. Moreover, the 1, 3, 5, and 10% Ce-doped glasses showed the TSL dose response from 10 mGy to 10 Gy with a proportional relationship.

DOI： 10.18494/SAM3680

Publishing type：Research paper (scientific journal)  

We synthesized Tm-doped NaMgF3 crystals and investigated their scintillation, optically stimulated luminescence (OSL), and thermally stimulated luminescence (TSL) properties. All the crystals showed multiplex luminescence peaks. Judging from the emission wavelength and scintillation decay time constants, Tm3+ acts as a luminescence center in NaMgF3 crystals. The 0.3% Tm-doped crystal showed the highest scintillation, OSL, and TSL intensities. The 0.3% Tm-doped crystal showed a linear relationship from 0.01 to 100 mGy for its TSL dose response function. This lower detection limit is comparable to that of some commercial products. In addition, we succeeded in 2D X-ray imaging using the TSL of the crystal.

DOI： 10.18494/SAM3685

Publishing type：Research paper (scientific journal)  

A glass phosphor is an attractive material for applications in radiation detection because of its high workability and availability with a wide range of chemical compositions. Recently, the X-ray-induced luminescence of glasses containing various luminescent activators has been actively investigated worldwide. Among them, glass that exhibits the radio-photoluminescence (RPL) phenomenon is a promising material for not only dosimetry but also X-ray imaging applications. However, there are only a few materials that exhibit the RPL phenomenon, and thus there is room for material exploration. In this study, we found that Ag2O–R2O–BaO–Al2O3–P2O5 (R = K, Rb, Cs) glass, in which some of the constituents of the commercial RPL glass were replaced with heavy elements, shows RPL properties worthy of practical application. Our glass specimens have a spatial resolution of at least 8 LP/mm; furthermore, the fading of the emission from RPL centers was much lesser than that from commercial imaging plates.

DOI： 10.18494/SAM3695

Publishing type：Research paper (scientific journal)  

We fabricated Pr3+-activated glasses having a composition of 10SrO–5Al2O3–85TeO2 (PSAT) for potential use as radiation detectors, and their photoluminescence (PL) and X-ray-induced scintillation properties were then characterized. The PSAT glasses showed several emission peaks in their PL spectra owing to the 4f–4f transitions of Pr3+. Furthermore, they exhibited typical PL decay times (0.09–0.86 ms), where the decay originated from the 4f–4f transitions of Pr3+. In the scintillation spectra of the PSAT glasses, three peaks at approximately 480, 618, and 636 nm were observed. The scintillation decay times were 0.747–0.840 ms, corresponding to the 4f–4f transitions of Pr3+. Furthermore, the PSAT glasses showed afterglow levels of 352–521 ppm, and the lowest afterglow level (352 ppm) was comparable to that of Tl-activated CsI single crystal.

DOI： 10.18494/SAM3689

Publishing type：Research paper (scientific journal)  

We evaluated the photoluminescence (PL), scintillation, and dosimetric properties of Ce–doped Mg2SiO4 single crystals. As the PL and optically-stimulated luminescence (OSL) properties, the Ce–doped Mg2SiO4 showed the emission from 5d to 4f transitions of Ce3+. In the scintillation and thermally-stimulated luminescence (TSL) properties, two emission peaks due to Ce3+ and defect centers were observed. The Ce–doped Mg2SiO4 showed OSL by stimulating at 600 nm and TSL by heating at 50, 160, 195, and 370 °C. In OSL, linearly proportional responses were confirmed from 10 mGy for the 0.5 and 1% Ce–doped samples to 100 mGy for the 0.1% Ce–doped sample. In TSL, the undoped and Ce–doped samples had the linearity response from 100 to 0.01 mGy, respectively.

DOI： 10.1007/s10854-021-06962-8

Publishing type：Research paper (scientific journal)  

Undoped and Ce-doped LiAlO2 single crystals, a novel neutron scintillator, were synthesized by the floating zone method, and the photoluminescence and scintillation properties were investigated. Under X-ray irradiation, all the synthesized crystals showed luminescence due to oxygen vacancies with decay time constants of 250 ns and 2 ¯s, and Ce-doped LiAlO2 crystals showed luminescence due to the 5d4f transition of Ce3+ with a decay time constant of 40 ns as well. In the pulse height spectra under neutron irradiation from 252Cf, the synthesized crystals exhibited thermal neutron peak, and scintillation light yields increased by doping of Ce. Furthermore, neutron and gamma-ray pulse shape discrimination was examined, and 0.5 and 1.0 % Ce-doped ones showed a distinction of neutron and gamma-ray events.

DOI： 10.2109/jcersj2.20233

Publishing type：Research paper (scientific journal)  

In this paper, we have prepared Dy-doped MgAl2O4 single crystals by the Floating Zone (FZ) method and investigated photoluminescence (PL), scintillation, and thermally stimulated luminescence (TSL) properties. In PL and scintillation, origins of luminescence at around 480, 580, and 660 nm of synthesized crystals were assigned to the 4f–4f transitions of Dy3+. In TSL, three glow peaks at around 50, 220, and 350 °C were observed, and these peaks were attributed to cation antisites and V center. The 0.1 % Dy-doped MgAl2O4 single crystal showed the highest intensity in TSL glow curves among the prepared crystals and higher sensitivity than those in ceramic-form MgAl2O4.

DOI： 10.1016/j.ijleo.2021.166498

Publishing type：Research paper (scientific journal)  

Optical and dosimetric properties of Ti-doped (0.05, 0.1, 0.2, and 0.5%) MgAl2O4 single crystals grown by the floating zone method were investigated. All Ti-doped MgAl2O4 single crystals showed photoluminescence (PL) and thermally stimulated luminescence (TSL) at 470 nm. The PL decay time constant of this luminescence was approximately 6 μs, and the emission origin was ascribed to charge transfer (CT) related to Ti4+. The 0.1% Ti-doped MgAl2O4 single crystal showed the highest intensity of TSL glow peaks unlike the result of PL quantum yields (QYs). In TSL dose response functions, 0.1 and 0.2% Ti-doped MgAl2O4 single crystals showed detection limit that comparable with some commercial products.

DOI： 10.1016/j.radphyschem.2020.109163

Publishing type：Research paper (scientific journal)  

The Ce-substituted (Ce x , Pr1-x )2Si2O7 bulk single crystals were synthesized by the floating zone method, and their photoluminescence (PL) and scintillation properties were evaluated. The X-ray diffraction patterns showed that all the synthesized samples were a single-phase of monoclinic Pr2Si2O7. In PL and scintillation, an emission peak was observed at around 370-390 nm due to the 5d-4f transitions of Ce3+. In pulse height spectra, the scintillation light yield was ∼400 ph MeV-1 in the 99% Ce-substituted sample. The 99% Ce-substituted sample showed the highest scintillation light yield among the present samples.

DOI： 10.35848/1347-4065/abc458

Publishing type：Research paper (scientific journal)  

Undoped and Tb-doped MgAl2O4 transparent ceramics were synthesized by the Spark Plasma Sintering (SPS) method, and dosimetric properties were investigated. The Tb-doped sample showed thermally stimulated luminescence (TSL) and optically stimulated luminescence (OSL), in which the emission center was Tb3+ ions. The TSL glow peaks of the Tb-doped sample are detected at 64, 151, 235, 299, and 385 °C. The Tb-doped sample had a linear TSL response in a dose range from 0.01 to 1000 mGy.

DOI： 10.1016/j.radmeas.2020.106341

Publishing type：Research paper (scientific journal)  

The undoped and Ce-doped MgAl2O4 single crystals were synthesized by the floating zone method equipped with four xenon arc lamps, and the photoluminescence (PL), scintillation, and dosimetric properties were investigated. The Ce-doped crystals showed PL emission peaks at around 420 and 720 nm. The former was ascribed to the 5 d-4f transition of Ce3+ ion, and the latter was ascribed Mg deficiency. The PL decay time profiles of the Ce-doped crystals exhibited the fast decay, and the decay time constants were the typical value of others Ce-doped materials. Thus, the decay time constants were attributed to the 5 d-4f transitions of Ce3+ ion. In addition, optically-stimulated luminescence (OSL) signals could be detected in all the crystals when the stimulation wavelength was 470 nm. The OSL dose response functions showed linearly proportional relationship from 10 to 1000 mGy in all the Ce-doped crystals. The thermally-stimulated luminescence (TSL) glow curves exhibit three peaks due to antisite of Al3+ ion, V center and antisite of Mg2+ ion. All the Ce-doped crystals showed improved TSL intensity and dose response sensitivity compared the undoped crystal. The 0.2 and 1% Ce-doped crystals showed linearly response at the dose range of the 0.1–1000 mGy.

DOI： 10.1016/j.jlumin.2020.117139

Publishing type：Research paper (scientific journal)  

Mn-doped MgAl2O4 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 Mn2+ 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 Mn2+ ion. In both TSL and OSL dose–response functions, the 0.1% Mn-doped crystal showed linearly response from 0.01 to 1000 mGy.

DOI： 10.1007/s10854-020-03359-x

Publishing type：Research paper (scientific journal)  

The photoluminescence (PL), scintillation, and dosimetric properties of Tb-doped MgAl2O4 single crystals were evaluated. In terms of PL and scintillation properties, the Tb-doped crystals showed some emission peaks ascribed to the 4f-4f transitions of the Tb3+ ion. In addition, the optically and thermally stimulated luminescence (OSL and TSL) spectra showed emission peaks considered to be due to the Tb3+ ion. TSL dose response functions were also evaluated, and the Tb-doped crystals showed linear responses from 0.01 mGy.

DOI： 10.35848/1347-4065/ab887c

Publishing type：Research paper (scientific journal)  

Undoped and Tm-doped NaMgF3 single crystals were synthesized and investigated in terms of their scintillation and optically stimulated luminescence (OSL) properties. The synthesized samples were confirmed by X-ray diffraction to be a single-phase NaMgF3. The Tm-doped sample showed an X-ray-induced scintillation spectrum characterized by sharp emission lines owing to the 4f–4f transitions of Tm3+. The OSL spectrum of the Tm-doped sample also showed emission at around 360 nm, which was ascribed to the 4f–4f transitions of Tm3+. The OSL dose response function of the Tm-doped sample showed a linear response in the dose range of 1–10000 mGy.

DOI： 10.18494/SAM.2020.2717

Publishing type：Research paper (scientific journal)  

We have developed a non-doped LiF/CaF2 eutectic for thermoluminescence (TL) dosimetry. The LiF/CaF2 eutectic were obtained using a simple melt-solidification method with a lower melting temperature than that of CaF2. The LiF/CaF2 eutectic showed the lower scintillation intensity than that of a CaF2 single crystal. In contrast, the TL intensity of the LiF/CaF2 eutectic was significantly higher than that of the CaF2 single crystal. Furthermore, it monotonically increased as a function of X-ray dose from 0.1 to 3000 mGy.

DOI： 10.1016/j.radmeas.2020.106254

Publishing type：Research paper (scientific journal)  

Different concentrations of Eu doped LiMgAlF6 samples were synthesized by the spark plasma sintering (SPS) method. In photoluminescence (PL) measurements, emission due to 5d-4f transition of Eu2+ was observed at 370 nm, and PL decay times resulted 1.1–2.8 μs. When we irradiated X-rays, scintillation emissions due to Eu2+ and Eu3+ were detected at 370 and 600 nm, respectively. Optically stimulated luminescence (OSL) and thermally stimulated luminescence (TSL) were also observed in Eu-doped LiMgAlF6, and especially, TSL intensity was very high.

DOI： 10.1016/j.radmeas.2020.106250

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Presentation type：Oral presentation (general)  

Presentation type：Poster presentation  

Presentation type：Poster presentation  

Presentation type：Poster presentation  

Presentation type：Oral presentation (invited, special)