共查询到20条相似文献,搜索用时 0 毫秒
1.
Kentaro Fukuda Noriaki Kawaguchi Sumito IshizuTomohito Nagami Toshihisa SuyamaTakayuki Yanagida Yuui YokotaMartin Nikl Akira Yoshikawa 《Optical Materials》2011,33(6):924-927
Sixty millimeter diameter single crystal of Nd3+ doped LiLuF4 was successfully grown by the Czochralski technique. No remarkable absorption due to unfavorable impurities was observed from optical absorption measurements in the vacuum ultra-violet spectral region. The high crystallinity and homogeneous luminescence characteristics were found from X-ray rocking curve and cathode-ray luminescence respectively. X-ray excited luminescence spectrum was measured and the significant 4f25d-4f3 luminescence at 182 nm was observed in the grown crystal. The pulse height spectrum was taken upon γ-ray irradiation. As a result, the grown crystals demonstrated sufficient response to the γ-ray showing the light yield of 420 ± 30 photons/MeV. The decay curve under α-ray irradiation was also investigated and described by two component decay kinetics which consists of the decay constants of 34 and 450 ns. 相似文献
2.
Hidehiko Tanaka Noriaki Kawaguchi Naoto AbeYuki Furuya Yuui YokotaTakayuki Yanagida Jan PejchalMartin Nikl Yoshiyuki KawazoeAkira Yoshikawa 《Optical Materials》2011,33(3):284-287
Nd3+ doped CaF2 single crystal scintillator has been investigated. We tried to grow 1%, 5%, 10%, 20%, 30% and 40% Nd3+ doped CaF2 single crystals by the simple melt-solidifying method. Powder X-ray diffraction (XRD) patterns were measured to identify the phase of all the samples. The XRD patterns of all the samples were similar to CaF2. Those samples are compared in terms of their X-ray-excited radioluminescence spectra, transmittance, α-ray-excited decay time and light yield. When the X-ray is used for excitation, luminescence is observed in the VUV region. Transmittance of the crystals is more than 70% at wavelengths longer than about 180 nm. In the decay kinetics, the fast components of the samples are distributed in less than 25 ns time range and the slow components of sample are distributed in more than 90 ns. These decay times became shorter with increasing Nd3+ concentration. They are related to the Nd3+ 5d-4f VUV emission. The light yields of samples are distributed in 5-2500 photon/5.5 MeV α-ray and decrease with increasing Nd3+ concentration. 相似文献
3.
Kentaro Fukuda Sumito IshizuNoriaki Kawaguchi Toshihisa SuyamaTakayuki Yanagida Yuui YokotaMartin Nikl Akira Yoshikawa 《Optical Materials》2011,33(8):1143-1146
Thirty millimeter diameter single crystal of Nd3+ doped LuF3 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 4f25d-4f3 transition of Nd3+ ion. The luminescence intensity of Nd:LuF3 under X-ray irradiation was significantly higher than that of reported VUV scintillators such as Nd:LaF3 or Nd:LiLuF4. 相似文献
4.
Makoto Sugiyama Yutaka FujimotoTakayuki Yanagida Yuui YokotaJan Pejchal Yuki FuruyaHidehiko Tanaka Akira Yoshikawa 《Optical Materials》2011,33(6):905-908
Nd 0.1%, 0.5%, 1% and 3% doped Lu3Al5O12 (Nd:LuAG) single crystals were grown in the nitrogen atmosphere by the micro-pulling down (μ-PD) method. The grown crystals had a single-phase confirmed by powder XRD analysis. In absorption spectra, some weak absorption lines due to Nd3+ 4f-4f transitions were observed and their intensity increased with the increase of Nd concentration. When excited by 241Am α-ray, a broad emission peak due to defects in the host lattice at 320 nm and some sharp lines due to Nd3+ 4f-4f transitions at wavelength longer than 400 nm were observed. The decay time profiles of Nd:LuAG under γ-ray excitation were well approximated by two exponential function of 340-760 ns and 3-5 μs for each sample. By pulse height measurement using 137Cs, Nd 0.5%:LuAG showed the highest light yield of 7600 ± 760 photons/MeV. 相似文献
5.
Akihiro Yamaji Takayuki YanagidaNoriaki Kawaguchi Yutaka FujimotoYuui Yokota Kenichi WatanabeAtsushi Yamazaki Akira Yoshikawa Jan Pejchal 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,659(1):368-372
Ce and Eu doped LiSrAlF6 (LiSAF) single crystals for the neutron detection with different dopant concentrations were grown by the micro-pulling-down method (μ-PD). In Ce:LiSAF, intense emission peaks due to Ce3+ 5d-4f transitions were observed at approximately 315 and 335 nm in photo- and α-ray induced radio-luminescence spectra. In case of Eu:LiSAFs, an intense emission peak at 375 nm due to Eu2+ 5d-4f transition was observed in the radio-luminescence spectra. The pulse height spectra and decay time profiles were measured under 252Cf 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. 相似文献
6.
Makoto Sugiyama Yutaka FujimotoTakayuki Yanagida Daisuke Totsuka Shunsuke KurosawaYoshisuke Futami Yuui YokotaValery Chani Akira Yoshikawa 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2012,664(1):127-131
Er-doped Lu3Al5O12 (Er:LuAG) single crystalline scintillators with different Er concentrations of 0.1, 0.5, 1, and 3% were grown by the micro-pulling-down (μ-PD) method. The grown crystals were composed of single-phase material, as demonstrated by powder X-ray diffraction (XRD). The radioluminescence spectra measured under 241Am α-ray excitation indicated host emission at approximately 350 nm and Er3+ 4f-4f emissions. According to the pulse height spectra recorded under γ-ray irradiation, the 0.5% Er:LuAG exhibited the highest peak channel among the samples. The γ-ray excited decay time profiles were well fitted by the two-component exponential approximation (0.8 μs and 6-10 μs). 相似文献
7.
Scintillation properties of Tm-doped Lu3Al5O12 single crystals 总被引:1,自引:0,他引:1
Makoto Sugiyama Yutaka Fujimoto Takayuki Yanagida Daisuke Totsuka Yuui Yokota Akira Yoshikawa 《Optical Materials》2011,34(2):439-443
Using the micro-pulling-down (μ-PD) method, Tm-doped Lu3Al5O12 (Tm:LuAG) single crystals were grown to examine their scintillation properties. In transmittance spectra, they exhibited about 80% transparency in the wavelengths longer than 320 nm and five absorption lines due to Tm3+ 4f–4f transitions were observed. 241Am α-ray excited radioluminescence spectra were measured and intense 4f–4f emission peaks were observed with the host emission. When excited by 137Cs γ-Ray to obtain pulse height spectra, Tm 1% doped LuAG showed the highest light yield coupled with a photomultiplier (PMT) or a silicon avalanche photodiode (Si-APD). The light yield was estimated to be 5800 and 7300 photons/MeV for PMT and Si-APD, respectively. Decay time profiles consist of two exponential components and the fast and slow components are considered to be attributed to the host and the combination of the host and Tm3+ 4f–4f emission, respectively. 相似文献
8.
Kei Kamada Takayuki YanagidaYutaka Fujimoto Akihiro FukaboriAkira Yoshikawa Martin Nikl 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,659(1):355-360
The Ca0.5% and Ce1%, 3%, 7%, 10% co-doped Gd0.5Y0.5F3 single crystals were grown by the μ-PD method. In the Ca0.5% and Ce3% co-doped sample, Ce3+-perturbed luminescence at 380 nm was observed with 32.4 ns photoluminescence decay time. The energy transfer in the sequence of the regular Ce3+→ (Gd3+)n→ the perturbed Ce3+ sites was evidenced through observation of decay time shortening of the regular Ce3+ and Gd3+ centers and the change between the Gd3+ and Ce3+-perturbed emission intensity. The gamma-ray excited scintillation response of the Ca0.5%, Ce7% co-doped Gd0.5Y0.5F3 sample was investigated with the help of the pulse height spectra and the light yield, energy resolution and non-proportionality was evaluated in the interval of energies of 59.4-1274 keV. 相似文献
9.
Takayuki Yanagida Noriaki Kawaguchi Yutaka FujimotoKentaro Fukuda Yuui YokotaAtsushi Yamazaki Kenichi WatanabeJan Pejchal Akira UritaniTetsuo Iguchi Akira Yoshikawa 《Optical Materials》2011,33(8):1243-1247
Eu2+ 0.1, 0.5, 1, and 2 mol% doped LiCaAlF6 single crystalline scintillators were grown by the micro-pulling down (μ-PD) method. Eu2+ 2 mol% doped LiCaAlF6 was also prepared using the Czochralski method. In the transmittance spectra, 4f-5d absorption lines appeared around 200-220 and 290-350 nm. An intense emission at 375 nm due to Eu2+ 5d-4f transition was observed under 241Am α-ray excitation. When 252Cf excited pulse height spectra were measured, Eu 2% doped one showed the highest light yield of 29,000 ph/n with 1.15 μs decay time. Using the 2 inchφ Czochralski grown one coupled with the position sensitive photomultiplier tube covered by Cd mask with various size (1, 2, 3, and 5 mm) pin holes, thermal neutron imaging was examined. As a result, the spatial resolution turned out to be better than 1 mm. 相似文献
10.
A blue-emitting phosphor of NaMg4(PO4)3:Eu2+, Ce3+ was prepared by a combustion-assisted synthesis method. The phase formation was confirmed by X-ray powder diffraction measurement. Photoluminescence excitation spectrum measurements show that the phosphor can be excited by near UV light from 230 to 400 nm and presents a dominant luminescence band centered at 424 nm due to the 4f65d1 → 4f7 transition of Eu2+ ions at room temperature. Effective energy transfer occurs in Ce3+/Eu2+ co-doped NaMg4(PO4)3 due to large spectral overlap between the emission of Ce3+ and excitation of Eu2+. Co-doping of Ce3+ enhances the emission intensity of Eu2+ greatly by transferring its excitation energy to Eu2+, and Ce3+ plays a role as a sensitizer. Ce3+-Eu2+ co-doped NaMg4(PO4)3 powders can possibly be applied as blue phosphors in the fields of lighting and display. 相似文献
11.
E. van der Kolk O.M. Ten KateJ.W. Wiegman D. BinerK.W. Krämer 《Optical Materials》2011,33(7):1024-1027
A high resolution luminescence study of NaLaF4: 1%Pr3+, 5%Yb3+ and NaLaF4: 1%Ce3+, 5%Yb3+ in the UV to NIR spectral range using a InGaAs detector and a fourier transform interferometer is reported. Although the Pr3+(3P0 → 1G4), Yb3+(2F7/2 → 2F5/2) energy transfer step takes place, significant Pr3+1G4 emission around 993, 1330 and 1850 nm is observed. No experimental proof for the second energy transfer step in the down-conversion process between Pr3+ and Yb3+ can be given. In the case of NaLaF4: Ce3+, Yb3+ it is concluded that the observed Yb3+ emission upon Ce3+ 5d excitation is the result of a charge transfer process instead of down-conversion. 相似文献
12.
Shaped single crystal growth and scintillating application of Yb:(Gd,Lu)3(Ga,Al)5O12 solid solutions
Shaped single crystals of (Yb0.05LuxGd0.95−x)Ga5O12 (0.0x0.9) and Yb0.15Gd0.15Lu2.7(AlxGa1−x)O12 (0.0x1.0) were grown by the modified micro-pulling-down method. Continuous solid solutions with garnet structure and a linear compositional dependency of crystal lattice parameter in the system Yb:(Gd,Lu)3(Ga,Al)5O12 are formed. Measured optical absorption spectra of the samples show 4f–4f transitions related to Gd3+ ion at 275 and 310 nm, and also an onset of charge transfer transitions from oxygen ligands to Gd3+ or Yb3+ cations below 240 nm. A complete absence of Yb3+ charge transfer luminescence under X-ray excitation in any of the investigated samples was explained by the overlapping of charge transfer absorption of Yb3+ by that of Gd3+ ions. For specific composition of Lu1.5Gd1.5Ga5O12 an intense defect––host lattice-related emission, which achieve of about 40% integrated intensity compared with Bi4Ge3O12, was found. 相似文献
13.
Comparing the luminescence properties of nanosized and macroscopic LaPO4:Ce,Tb powders are performed in wide spectral range using synchrotron radiation. In the present study, LaPO4:Ce,Tb nanopowder was produced by means of a microwave-induced synthesis in ionic liquids, whereas the bulk sample represents a commercial lamp phosphor. Emission and excitation of both, Ce3+ and Tb3+ luminescence, is observed to be different when comparing bulk and nanosized LaPO4:Ce,Tb. In particular, it was shown that the fine structure of the Ce3+ as well as the Tb3+ related emission is poorly resolved for the nanomaterial. It is suggested that the nanoparticles surface plays a key role regarding the perturbation of rare-earth ions and changes their luminescence properties. Furthermore, it is demonstrated that allowed f-d transitions on Tb3+ at high energy are significantly suppressed for nanosized LaPO4:Ce,Tb. Energy transfer is required to initiate Tb3+ emission even in the vacuum ultraviolet spectral range. 相似文献
14.
Hongbin Liang Zifeng TianHuihong Lin Mubiao XieGuobin Zhang Pieter DorenbosQiang Su 《Optical Materials》2011,33(4):618-622
The spectroscopic properties of Na3Gd(PO4)2 and Na3Gd(PO4)2:Ce3+ phosphors in the VUV-UV spectral range were investigated. Five excitation bands of Ce3+ ions at Gd3+ sites are observed at wavelengths of 205, 246, 260, 292, and 321 nm. Doublet Ce3+ 5d → 4f emission bands are observed at 341 and 365 nm with a decay constant τ1/e around 26 ns. The X-ray excited luminescence of Na3Gd0.99Ce0.01(PO4)2 at room temperature shows a photon yield of ∼17,000 photons/MeV of absorbed X-ray energy. 相似文献
15.
Takayuki Yanagida Yutaka FujimotoNoriaki Kawaguchi Yuui YokotaKei Kamada Daisuke TotsukaShun-Ichi Hatamoto Akira YoshikawaValery Chani 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,652(1):251-255
The crystals of 1 mol% Ce-doped LuLiF4 (Ce:LLF) grown by the micro-pulling down (μ-PD) method and 1 mol% Ce-doped LuScBO3 (Ce:LSBO) grown by the conventional Czochralski (Cz) method were examined for their scintillation properties. Ce:LLF and Ce:LSBO demonstrated ∼80% transparency at wavelengths longer than 300 and 400 nm, respectively. When excited by 241Am α-ray to obtain radioactive luminescence spectra, Ce3+ 5d-4f emission peaks were detected at around 320 nm for Ce:LLF and at around 380 nm for Ce:LSBO. In Ce:LSBO, the host luminescence was also observed at 260 nm. By recording pulse height spectra under γ-ray irradiation, the absolute light yield of Ce:LLF and Ce:LSBO was measured to be 3600±400 and 4200±400 ph/MeV, respectively. Decay time kinetics was also investigated using a pulse X-ray equipped streak camera system. The main component of Ce:LLF was ∼320 ns and that of Ce:LSBO was ∼31 ns. In addition, the light yield non-proportionality and energy resolution against the γ-ray energy were evaluated. 相似文献
16.
Manganese is a very important microelement performing a large number of biological functions in human body. We have detected by spectroscopic measurements manganese in mineral kyanite. In this paper we present laser-induced time-resolved luminescence and optical absorbance spectra of orange, Mn containing kyanite. It was proven the orange color is caused by Mn3+. Several luminescence lines and bands were found and ascribed to Mn4+ and Mn3+, emission centers. The spectroscopic technique can be utilized for detection of small amounts of manganese in minerals. 相似文献
17.
Takayuki Yanagida Mitsuhiro SatoKei Kamada Yutaka FujimotoYuui Yokota Akira Yoshikawa Valery Chani 《Optical Materials》2011,33(3):413-418
Pr:LuAG single crystalline scintillators with different Pr3+ concentration, 0.1, 0.18, and 0.22 mol% were grown by the Czochralski method. The crystals were cut to dimensions of 2.2 × 2.2 × 15 mm3 and polished, simulating sensors for Positron Emission Tomography (PET). Their absorption coefficients were examined, and the absorption strength was found to be proportional to the Pr concentration. The α-ray induced emission spectra of the samples demonstrated two emission lines peaking at 310 and 370 nm. The emission intensities in the radio luminescence spectra were also proportional to the Pr content. The absolute light yields and intrinsic energy resolution under γ-ray irradiation were evaluated at +20, 0, and −20 °C using avalanche photodiode as a photodetector. Pr 0.22% doped crystal had strongest light output of 16 400 ph/MeV, and its intrinsic energy resolution was around few % at several hundred keV. When coupled with PMT, the decay time was around 25 ns, and it was almost independent on concentration. 相似文献
18.
Z.Q. Wu J.F. Tang J.H. HuangX.H. Gong Y.J. ChenY.F. Lin Z.D. LuoY.D. Huang 《Optical Materials》2011,34(1):287-291
Trivalent thulium-doped K5Bi(MoO4)4 single crystals were grown by the Czochralski method. Its polarized absorption and fluorescence spectra and fluorescence decay curves were recorded at room temperature. On the basis of the Judd-Ofelt theory, the spectral parameters of the Tm3+:K5Bi(MoO4)4 crystal were calculated. The cross relaxations between Tm3+ ions were analyzed. The emission cross sections of the 3F4 → 3H6 transition were obtained by the Fuchtbauer-Ladenburg formula and then the gain cross sections around 1.9 μm were calculated. The peak emission cross section and width of emission band around 1.9 μm are comparable to those for Tm3+:YAG and the tunable range is about 280 nm for the potential ∼1.9 μm laser operation via the 3F4 → 3H6 transition. 相似文献
19.
Hiroko OgataSatoru Takeshita Tetsuhiko Isobe Tomohiro SawayamaSeiji Niikura 《Optical Materials》2011,33(11):1820-1824
YBO3:Ce3+ blue-emitting phosphors were prepared from boric acid and nitrates of yttrium and cerium(III) by hydrothermal method. An excess amount of boric acid, prolonged aging, high temperature, and a high pH value promote the formation of crystalline YBO3. The higher crystallinity results in the higher photoluminescence (PL) intensity corresponding to the 5d-4f transition of Ce3+ under the irradiation of near-UV light. The PL intensity also depends on the pH value of precursor suspension and the nominal Ce3+ concentration, where the sample prepared at pH = 8 and Ce/(Y + Ce) = 0.25-0.5 at% shows the maximum PL intensity. In addition, the hydrothermally prepared sample shows the characteristic photobleaching behavior under the continuous irradiation of near-UV light. These results suggest that the crystallinity of the host YBO3 crystal and the homogeneity of substituted Ce3+ ions play significant roles in the PL properties. 相似文献
20.
In the search for new scintillator materials, Ce3+ doped chlorides are a promising class of materials, combining a high efficiency and fast response time. Even shorter response times may be achieved by replacing Ce3+ by Pr3+ or Nd3+ as the lifetime of the d-f emission is substantially shorter for these ions. Here we report on the luminescence properties of Ce3+, Pr3+ and Nd3+ in RbCl and investigate the potential as a scintillator material. Under UV excitation Ce3+ shows d-f emission between 325 and 425 nm. The emission originates from multiple (differently charge compensated) Ce3+ sites. The luminescence lifetime varies with wavelength and is ∼40 ns for the longer wavelength emission. For RbCl:Pr3+ three d-f emission band are observed between 250 and 350 nm which can be assigned to transitions from the lowest energy fd state to different 3HJ (J = 4-6) states within the 4f2 configuration of Pr3+. The decay time is ∼17 ns. For the Nd3+ activated sample a weak emission band around 220 nm is observed only at 8 K which may be due to d-f emission. The very short lifetime (4 ns) is faster than the radiative lifetime, indicating that the d-f emission is quenched by relaxation to lower lying 4f3 states or by the process of photoionization. Under VUV excitation at wavelengths below 175 nm (the bandgap of RbCl) the d-f emission is very weak for Ce3+, Pr3+ and Nd3+ doped RbCl and the emission spectra are dominated by defect related emission. This indicates that energy transfer from the host lattice to the fd states is inefficient which prevents application as a scintillator material. 相似文献