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ABSTRACT: We present the luminescent and scintillation characteristics of CsI:CO<sub>3</sub> single crystals. The CsI:CO<sub>3</sub> single crystals were grown by using Czochralski method for different concentrations of CO<sub>3</sub> from 0.007 to 0.1 mole%. The crystals were cut into a size of 10 mm times 10 mm times 5 mm. The luminescent characteristics were measured with X-rays to study the emission spectra of the CsI:CO<sub>3</sub> crystals. The scintillation properties of the CsI:CO<sub>3</sub> crystals such as fluorescence decay time, energy resolution, pulse height spectra, proportionality, and relative light output were studied by using various gamma-ray sources with a photomultiplier tube (PMT) at room temperature. The absolute light outputs of the crystals were also measured with an avalanche photo-diode (APD).
IEEE Transactions on Nuclear Science 07/2009; · 1.45 Impact Factor
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ABSTRACT: In this paper, crystal growth and scintillation properties of Rb<sub>2</sub>CeBr<sub>5</sub> crystal are presented. The crystal was grown with the Bridgman method using a two zone transparent furnace. The investigation of scintillation properties of the crystal were performed under the excitation by X-ray and gamma;-ray at room temperature. The emission spectrum of the Rb<sub>2</sub>CeBr<sub>5</sub> was observed in the range of 360 ~ 440 nm, peaking at 390.5 nm, which is due to the 5d rarr 4f transitions of the Ce<sup>3+</sup>. The decay time of the Ce<sup>3+</sup> emission was composed two components. The fast component was 56.1 ns (98.8%), and the slow component was 329.9 ns (1.2%). The energy resolution of the crystal was obtained to be 6.9% for the <sup>137</sup>Cs 662 keV gamma-ray. The absolute light yield of the Rb<sub>2</sub>CeBr<sub>5</sub> crystal is about 34,000 phs/MeV, and the non-proportionality of the crystal was also measured.
IEEE Transactions on Nuclear Science 07/2009; · 1.45 Impact Factor
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ABSTRACT: Crystal growth, luminescence, and scintillation properties of a CeBr<sub>3</sub> crystal are presented. The crystal was grown with Bridgman method using two-zone transparent furnace and cut to Oslash10 times 10 mm<sup>3</sup>. The investigation of luminescence and scintillation properties of the CeBr<sub>3</sub> was performed under the excitation by ultraviolet and gamma-rays at room temperature. The emission spectrum of the CeBr<sub>3</sub> was observed in the range of near ultraviolet to violet, which is due to the 5d rarr 4f transition of Ce<sup>3+</sup>. The decay time of the Ce<sup>3+</sup> emission was measured to be approximately 20 ns. The energy resolution of the CeBr<sub>3</sub> single crystal was obtained to be 4.9% for the <sup>137</sup>Cs 662 keV gamma-rays. The relative signal of the CeBr<sub>3</sub> crystal by the <sup>137</sup>Cs gamma-rays is about three times higher than that of a CsI:Tl crystal when a bi-alkali PMT was used. The nonproportionality in the gamma-ray energy of the crystal was also measured. The study showed that the CeBr<sub>3</sub> crystal is the promising candidate for the PET application. The CeBr<sub>3</sub> crystal with high light output and fast decay time affords its use for the particle detection in a high counting rate environment such as nuclear and high-energy physics.
IEEE Transactions on Nuclear Science 07/2008; · 1.45 Impact Factor
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ABSTRACT: In this paper, we present scintillation properties of the new developed single crystals of Ba<sub>x</sub>Sr<sub>1-x</sub>Cl<sub>2</sub> for different concentration of x. We manufactured Ba<sub>0.12</sub>Sr<sub>0.88</sub>Cl<sub>2</sub>, Ba<sub>0.20</sub>Sr<sub>0.80</sub>Cl<sub>2</sub>, Ba<sub>0.22</sub>Sr<sub>0.78</sub>Cl<sub>2</sub> crystals, and CsI(Tl) crystal as reference by using the Czochralski method. The crystals were cut into a size of 5 times 10 times 10 mm<sup>3</sup>. The X-ray diffraction technique was used to verify the structure of crystals. The emission spectra were measured with X-ray excitation at room temperature. Scintillation properties of the crystals such as pulse height spectra, energy resolution, alpha/beta ratio, relative light output, proportionality, and fluorescence decay time were measured with the various radioactive gamma sources at room temperature. The light output of these crystals were compared with that of the CsI(Tl) crystal. The differences in relative light outputs, energy resolutions, and decay times among these crystals were studied in detail.
IEEE Transactions on Nuclear Science 07/2008; · 1.45 Impact Factor
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ABSTRACT: The aim of this study is to develop scintillation crystals for the study of neutrinoless beta<sup>+</sup>/EC decay process. The <sup>84</sup>Sr isotope is one of the potential candidates for the neutrinoless beta<sup>+</sup>/EC decay process. None of the scintillation crystals containing a strontium element up till now were used for the study of neutrinoless beta<sup>+</sup>/EC decay process. In general our crystal growth program include studies of starting material preparation, growth procedures and characterization of grown crystals. We grew a SrCl<sub>2</sub> single crystal by using the Czochralski method. The cylindrical shape of the SrCl<sub>2</sub> crystal was cut into the dimensions of Oslash2 times 1.5 cm<sup>3</sup>. The scintillation properties were studied by using various gamma ray sources and an alpha source. The scintillation properties such as energy resolution, light output, linearity and decay time were presented. In particular, the alpha/beta light ratio and possibility of a pulse shape discrimination between alpha and gamma quanta using a <sup>210</sup>Po alpha source were studied.
IEEE Transactions on Nuclear Science 07/2008; · 1.45 Impact Factor
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ABSTRACT: The concentrations of naturally occurring radioisotopes ((232)Th, (228)Th, (230)Th, (228)Ra, (226)Ra, and (40)K) in typical Korean foods were evaluated. The daily intakes of these radioisotopes were calculated by comparing concentrations in typical Korean foods and the daily consumption rates of these foods. Daily intakes were as follows: (232)Th, 0.00-0.23; (228)Th, 0.00-2.04; (230)Th, 0.00-0.26; (228)Ra, 0.02-2.73; (226)Ra, 0.01-4.37 mBq/day; and (40)K, 0.01-5.71 Bq/day. The total daily intake of the naturally occurring radioisotopes measured in this study from food was 39.46 Bq/day. The total annual internal dose resulting from ingestion of radioisotopes in food was 109.83 muSv/y, and the radioisotope with the highest daily intake was (40)K. These values were same level compiled in other countries.
Journal of Environmental Radioactivity 02/2008; 99(8):1319-23. · 1.34 Impact Factor
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ABSTRACT: The 239+240Pu content of the marine sediments and seawater of the costal sea of Korea was measured. In marine sediments the 239+240Pu concentrations were in the range of 0.11-1.91 Bq/kg dry weight and in the coastal sea of Korea the ratio of 239+240Pu/137Cs was 0.27. The correlations between 239+240Pu and 137Cs concentrations and the content of organic matter (C, O, H, N, S) as well as the grain size of marine sediment were investigated
by regression analysis. The distribution coefficient of 239+240Pu was 1.22. 105. The 239+240Pu concentration in seawater increased with seawater depth. However, the 137Cs concentration in seawater did not change considerably with depth.
Journal of Radioanalytical and Nuclear Chemistry 03/2006; 268(1):103-108. · 1.52 Impact Factor
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ABSTRACT: We report on a new scintillation crystal, CsCe2Cl7, for γ-ray spectroscopy. The crystal was grown using the Czocralski pulling method. X-ray excited luminescence measurements of the CsCe2Cl7 showed a broad emission band in the wavelength range from 370 to 470 nm with a peak centre at 410 nm. An energy resolution (FWHM of peak position) for the 662 keV full energy peak of 5.5% was observed at room temperature. The results showed a good proportionality for light output versus γ-ray energy. The light output deviation from the linear response is about 10% between the energy range of 31 and 1333 keV. We measured a light yield of 28,000 photons/MeV of absorbed γ-ray energy. The scintillation decay curve of CsCe2Cl7 can be described by a single exponential decay function with a decay time of 50 ns. Overall, these measurements clearly indicate that CsCe2Cl7 can exhibit attracting scintillation properties, and we believe that the CsCe2Cl7 crystal is a promising material for medical imaging and radiation detection.
Journal of Crystal Growth 311(1):128-131. · 1.73 Impact Factor
