Crystal Growth and Evaluations of { {Nd}}{ {:LuLiF}}_{4} Scintillators for Different Nd Concentration (original) (raw)
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IEEE Transactions on Nuclear Science, 2000
In order to develop novel scintillating materials, we grew 0.5 mol%, 1 mol%, and 3 mol% Nd-doped LuLiF 4 scintillators by the micro-pulling down method, because LuLiF 4 has a very wide band gap and Nd 3+ shows fast and intense 5d-4f emission as a luminescence center. The transmittance and emission peaks were examined in these three samples by using our original spectrometer made by Bunkou-Keiki Company. At wavelengths longer than 180 nm, approximately 60-80% transmittance with three absorption peaks around 140, 160 and 175 nm and emission peak at approximately 180 nm were observed for all the crystals. Light yields and decay time constants of the samples irradiated by 241 Am -ray were measured using photomultiplier tubes R8778 (Hamamatsu). The light yield of the 1 mol% doped LuLiF 4 was 700 photons/5.5MeV that is much greater than that of Nd:LaF 3 scintillator (100 photons/5.5MeV ). As for decay time profiles, the main component of Nd:LuLiF 4 was 12 ns in the case of -ray irradiation. 137Cs 662 keV -ray photoabsorption peak was detected in 1 mol% doped LuLiF 4 only, and the light yield was 300 ph/MeV.
Crystal growth and scintillation characteristics of the Nd3+ doped LaF3 single crystal
Optical Materials, 2010
Two-inch diameter Nd 3+ doped LaF 3 single crystals were successfully grown by the Czochralski technique. No remarkable absorption due to unfavorable impurities or color centers was observed from optical absorption measurements in the vacuum ultra-violet spectral region. The high crystallinity and homogeneous Nd 3+ distribution were found from X-ray rocking curve and chemical composition analysis, respectively. X-ray excited luminescence spectrum was measured and the significant 4f 2 5d-4f 3 luminescence at 173 nm was observed in the grown crystal. The pulse height spectrum and scintillation decay curves were taken upon c-ray irradiation. As a result, the grown crystals demonstrated sufficient response to the c-ray, the light yield of 140 ± 30 photons/MeV, and fast scintillation decay of 7.6 ns.
Crystal growth and optical properties of the Nd3+ doped LuF3 single crystals
Optical Materials, 2011
Thirty millimeter diameter single crystal of Nd 3+ doped LuF 3 was grown using LiF as solvent. The single phase crystallization was confirmed by the powder X-ray diffraction, and high structural perfection was demonstrated by X-ray rocking curve (XRC) measurements. FWHM of XRC for 220 reflection was 32 arcsec. No remarkable absorption due to unfavorable impurities was observed from optical absorption measurements in the VUV spectral region. The crystal showed the VUV luminescence peaking around 178 nm that is consistent with the 4f 2 5d-4f 3 transition of Nd 3+ ion. The luminescence intensity of Nd:LuF 3 under X-ray irradiation was significantly higher than that of reported VUV scintillators such as Nd:LaF 3 or Nd:LiLuF 4 .
Journal of Crystal Growth, 2013
The Nd-doped Lu 3 Al 5 O 12 (Nd:LuAG) single crystal was grown by the Czochralski (CZ) method. In XRC profiles, the full-width at half-maximum (FWHM) value was 58 arcsec, which was much higher than that of the m-PD (194 arcsec). In photo and radio-luminescence spectra, the CZ grown sample showed strong emission peaks attributed to Nd 3 þ 4f-4f transitions in visible wavelengths longer than 400 nm. The Nd:LuAG grown with the CZ method showed light yield of 7900 photons/MeV, which is comparable with the standard BGO and energy resolution of 14% under 137 Cs g-ray excitation.
Optical Materials, 2015
Nd 1 mol% doped (Lu, Gd) 3 (Ga, Al) 5 O 12 (LGGAG) single crystals were grown by the micro-pulling down 27 (l-PD) method. Luminescence and scintillation properties such as absorption, excitation and emission 28 spectra, light yield and decay time were evaluated. Nd1%:Lu 3 Al 5 O 12 showed the highest light output of 29 around 8200 photons/MeV among the grown crystals. Scintillation decay time of Nd:Y 3 Al 5 O 12 was 30 1.32 ls (36%) 2.02 ls (64%). Nd:Lu 3 Ga 3 Al 2 O 12 was relatively high dense scintillator of 7.38 g/cm 3 with 31 good light yield of 6800 photons/MeV and scintillation decay time of 0.20 ls (5%) 2.60 ls (95%).
Radiation Measurements, 2016
T h e n s 2-type metal elements (Pb and Sn) doped LiCaAlF6 single crystals were grown by a micro-pulling-down (-PD) method. Pb doped LiCaAlF6 [Pb:LiCAF] crystals showed high transparency and single phase of the LiCAF structure. However, we could not obtain Sn:LiCAF crystals due to the evaporation of SnF2 during the crystal growth. There was an absorption peak around 193 nm in the transmittance spectrum of Pb:LiCAF crystal. In the radioluminescence spectrum of the Pb:LiCAF crystal under X-ray irradiation, two emission peaks around 200 and 830 nm were observed.
Luminescence Mechanism in Doubly Doped rmLaF3{\rm LaF} _{3}rmLaF3:Er,Nd VUV Scintillator
IEEE Transactions on Nuclear Science, 2010
Doubly doped LaF 3 :Er, Nd scintillation crystals were grown by modified micropulling-down method. The Er codoping was chosen to enhance the energy transfer from the host lattice to the Nd 3+ luminescence center via the 5d-levels of Er 3+ , which can be enabled by the overlap of Er 3+ 5d-4f emission spectrum with the Nd 3+ 4f-5d absorption. However, no relevant energy transfer was found by photo-and radioluminescence spectra measurements. The reasons of no significant positive effect of Er codoping are discussed.
Crystal growth and scintillation properties of Tm:K2NaLuF6
Optical Materials, 2010
Ce and Eu doped LiSrAlF 6 (LiSAF) single crystals for the neutron detection with different dopant concentrations were grown by the micro-pulling-down method (m-PD). In Ce:LiSAF, intense emission peaks due to Ce 3 þ 5d-4f transitions were observed at approximately 315 and 335 nm in photo-and a-ray induced radio-luminescence spectra. In case of Eu:LiSAFs, an intense emission peak at 375 nm due to Eu 2 þ 5d-4f transition was observed in the radio-luminescence spectra. The pulse height spectra and decay time profiles were measured under 252 Cf neutron irradiation to examine the neutron response. The Ce 3% and Eu 2% doped LiSAF showed the highest light yield of 2860 ph/n with 19 ns main decay time component and 24,000 ph/n with 1610 ns.
Luminescence mechanism in doubly Gd, Nd-codoped fluoride crystals for VUV scintillators
Journal of Luminescence, 2016
The Nd-doped, Gd-doped and doubly Nd,Gd-codoped BaLu1.2Y0.8F8 (BaLuYF) and LuF3 single crystals were grown by micro-pulling-down method. Their photoluminescence, radioluminescence and alpha-ray-excited pulse-height spectra were studied in the vacuum-ultraviolet (VUV) region to confirm their possible application as fast VUV scintillators. Complementary photoluminescence measurements in the ultra-violet/ visible spectral region were performed as well. The possibility of scintillation performance improvement by Gd codoping was tested. The overall scintillation efficiency of BaLuYF:Nd1% was comparable to that of the LaF3:Nd8% reference sample and only slight improvement was observed after Gd1% codoping. The positive effect of Gd codoping was confirmed for higher dopant concentrations. This was explained by an energy transfer from the high-energy Gd 3+ 4f 2 G(0)7/2 level to the Nd 3+ 5d state. On the other hand, pulse-height spectra showed degradation of the light yield under alpha-ray excitation, which was explained by introduction of slow components due to Gd codoping. On the other hand, no positive effect of Gd codoping was found for the overall scintillation efficiency of Nd-doped LuF3, despite the same energy transfer process was confirmed. Slight improvement of the light yield under alpha-ray excitation was confirmed.