Growth and radioluminescence of metal elements doped LiCaAlF6 single crystals for neutron scintillator (original) (raw)
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Optical Materials, 2014
Sr co-doped Ce:LiCaAlF 6 [Ce:Li(Ca,Sr)AlF 6 ] crystals with various Ca/Sr ratios were grown by a micro-pulling-down (-PD) method and effects of Sr co-doping on crystal structure, chemical composition, optical and scintillation properties for Ce:LiCaAlF 6 crystals were investigated as a neutron scintillator. High transparent Ce2%:Li(Ca,Sr)AlF 6 crystals with 2% and 5% Sr contents were obtained while Ce2%:Li(Ca,Sr)AlF 6 crystals with 10% and 20% Sr contents included milky parts in the crystals. a-and c-axis lengths of Ce:Li(Ca,Sr)AlF 6 phase systematically increased with an increase of Sr content. In addition to the emission at 284 and 308 nm from Ce 3+ ion, emission peaks at 367 nm appeared by Sr co-doping.
Optical Materials, 2011
Eu 2+ 0.1, 0.5, 1, and 2 mol% doped LiCaAlF 6 single crystalline scintillators were grown by the micro-pulling down (l-PD) method. Eu 2+ 2 mol% doped LiCaAlF 6 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 Eu 2+ 5d-4f transition was observed under 241 Am a-ray excitation. When 252 Cf excited pulse height spectra were measured, Eu 2% doped one showed the highest light yield of 29,000 ph/n with 1.15 ls decay time. Using the 2 inchu 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.
Neutron detection with LiCaAlF6 scintillator doped with 3d-transition metal ions
Radiation Measurements, 2013
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights ► Neutron detection with 3d-transition metal ions doped LiCaAlF6 is investigated. ► Single crystals of Ti, V, Mn, Fe, Co, Ni and Cu doped LiCaAlF6 are grown. ► In α-ray induced emission spectra, Mn doped LiCaAlF6 showed highest intensity. ► Mn doped LiCaAlF6 coupled with Si-APD exhibited a clear neutron signal.
Optical Materials, 2009
Ce 1%, 2%, and 3%-doped LiCaAlF 6 (LiCAF) single crystals were grown by the micro-pulling-down method. The crystals were transparent, 2.0 mm in diameter and 30-60 mm in length. Neither visible inclusions nor cracks were observed. Optical properties, including absorption coefficient, and photoluminescence emission spectra were measured. The strong absorption line was observed at 260 nm, and absorption coefficients of this line were proportional to Ce 3+ concentration. Emission due to Ce 3+ 5d-4f transition peaking around 285 nm and 310 nm were observed by 260 nm excitation. Simulating a neutron irradiation, 241 Am 5.5 MeV a-ray was used to excite the samples. After a correction of a quantum efficiency of photomultiplier tube and compared with Li-glass scintillator GS20, light yield of 6600 ph/n, and 41 ns decay were achieved 3% doped.
Crystal growth and thermal neutron scintillation response of Ce doped K6LiYF5
Optical Materials, 2011
a b s t r a c t K 6 Li(Y 1Àx Ce x )F 5 (x = 0.003, 0.02) single crystals were grown from the melt using the precise atmosphere control type Micro-Pulling-Down (l-PD) method to examine their potential as a new thermal neutron scintillators. The grown crystals were single-phase materials as confirmed by XRD. The crystals demonstrated 40-60% transmittance above 320 nm and Ce 3+ 5d-4f luminescence observed around 340 nm when exited by a-ray. The radio luminescence measurements under thermal neutron excitation ( 252 Cf) demonstrated the light yield of 890 (Ph/neutron) and the decay time excited by a-ray exhibited 20 and 259 ns.
Growth and optical properties of LiF/LaF3 eutectic crystals
Journal of the European Ceramic Society, 2014
Neutron imaging devices employing a scintillator can be used in various fields, and eutectic crystals can be suitable for the imaging with a fine position resolution of a few hundred m. Since LiF and LaF 3 have different refractive indexes of 1.41 and 1.64 at 300 nm, respectively, the eutectic crystal is expected to behave as a scintillator with light guiding properties. Thus, the optical properties of Ce-doped LiF/LaF 3 eutectic crystal grown by micro-pulling down method were investigated. The light output of LiF/Ce:LaF 3 eutectic crystal was relatively small. The emission peaks at 300 nm originating from Ce 3+ of 5d-4f transition were observed under excitation by UV photons and 5.5MeV alpha rays. Moreover, the photo-luminescence decay time of Ce-doped LiF/LaF 3 eutectic crystal was estimated to be 17 1 ns.
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.
Optical Materials, 2014
Abstract Eu doped LiSrAlF6 (Eu:LiSAF) crystals with various Eu concentrations were grown by a micro-pulling-down (μ-PD) method and the effects of Eu concentration control on crystal growth and scintillation properties for Eu:LiSAF crystals were investigated as a neutron scintillator. As-grown Eu0.3%:LiSAF crystal had no visible inclusion while milky parts were observed in the crystals with higher Eu contents. The secondary phases with the chemical composition of EuF2 or EuF3 in the Eu:LiSAF matrix were observed for the crystals with high Eu contents while the secondary phase couldn’t be observed in the powder XRD patterns. In the radioluminescence spectra of Eu:LiSAF crystals under α-ray irradiation, emission peaks around 375 nm originated from 5d–4f transition of Eu2+ ion were observed. The light yields systematically increased with an increase of actual Eu contents in the crystals and the decay times were 1490–1620 ns.