• Progress in Medical Physics
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• v.16 no.4
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• pp.202-206
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• 2005

Three-dimensional thermoluminescence (TL) spectra from $MgAl_2O_4$ irradiated with UV light were measured over 300${\~}$600 K and 300${\~}$800 nm. The peak positions of TL glow curves were shifted to lower temperature with increasing the exposure time of UV light. The 476 K TL glow curve is due to the second kinetics and its activation energy and escape frequency factor are calculated to be 0.85 eV and $1.92{\times}10^6 sec^{-1}$, respectively The TL spectra were split into 530 nm and 700 nm emission bands which were associated with $V^{2+}$ and $Cr^{2+}$, respectively. The linearity range of 700 nm omission band is smaller than that of 530 nm emission band, but the saturation time of 700 nm emission band is longer than that of 530 nm omission band.

• Progress in Medical Physics
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• v.3 no.1
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• pp.9-18
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• 1992

In this study, beta-eucryptite is fabricated and the thermal parameters of this material have been investigated. The thermoluminescence from 4MeV X-ray irradiated beta-eucryptite have been measured over the temperature range of 300K-600K. Thermoluminescence curve from X-ray irradiated beta-eucryptite shows five peaks located at 342K, 392K, 438K, 474K, and 527K. $\tau$, $\delta$ and $\omega$ of peak at 527K are 35K, 39K and 74K, respectively and this peak is found to be 2nd order kinetics. The activation energy of peak shape method is calculated to be 1.03eV and the frequency factor for 527K curve is calculated to be 3.9x10$\^$8/sec$\^$-1/. Based on the various heating rates methods, the activation energy of the peak is computed to be 1.02${\pm}$0.05eV that is similar to 1.19${\pm}$0.03eV of initial rise method. The linearity of thermoluminescence intensity and radiation flux is valid up to 50Gy and beyond higher dose the supralinearity and saturation come out.

• Progress in Medical Physics
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• v.3 no.2
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• pp.23-31
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• 1992

The thermally stimulated luminecence (Thermoluminescence:TL) of manufactured beta-eucryptite was studied for dose range of 200cGy-20000Gy. The TL spectrum from cesium irradiated beta-eucryptite was measured over the temperature range of 300K to 600K. The linearity of TL intensity vs irradiation dose is valid up to 50Gy and beyond higher dose supralinearity and saturation come out. At the dose of 2000Gy, the net number of supralinearity is maximum. The net amount of supralinearity form newly formed trapping center by photon irradiation and totally calculated TL intensity are accord with the experimental results except for the 50Gy range that supralinearity appears.

• 대한방사선방어학회:학술대회논문집
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• 2011.04a
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• pp.30-31
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• 2011

• Progress in Medical Physics
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• v.4 no.2
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• pp.49-58
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• 1993

The complex glow curves were split into isolated glow curves to be calculated the values of kinetic order, activation energy, escape frequency and density of initial trap from the independent glow curves using the mathematical method of thermally stimulated processes. The minimization of the intensity difference between measured and theoretical glow curve was done by the nonlinear least-square program. The results of the fitted curves were almost equal to the actual values of the parameters. Thermoluminescence from gamma ray irradiated ${\alpha}$-Al$_2$ $O_3$ over the range of 300K to 600K was split into six glow curves. The kinetic order, activation energy and escape frequency of first glow curve were obtained as 1, 1.12eV and 6.79X10$\^$12/sec$\^$-1/, respectively, which were similar to the results of other method. Also the parameters of the second and the third glow curve and so forth were calculated.

• Progress in Medical Physics
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• v.12 no.1
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• pp.1-8
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• 2001

Diamond thin films were synthesized by a chemical vapor deposition (CVD). Raman spectrum showed the diamond line at 1332 $cm^{-1}$ / and x-ray diffraction pattern exhibited a strong (111) peak of diamond. The scanning electron microscopy analysis showed that the CVD diamond thin film was grown to be unepitaxial crystallites with pyramidal hillocks. A wavelength-resolved thermoluminescence (TL) of the CVD diamond thin film irradiated with X-rays showed one peak at 430 nm around 560 K. The glow curve of the CVD diamond thin film produced one dominant 560-K peak that was caused by first-order kinetics. Its activation energy and the escape frequency were calculated to be 0.92 ～ 1.05 eV and 1.34 $\times$ 10$^{7}$ sec$^{-1}$ , respectively. The emission spectrum at 560 K was split into 1.63-eV, 2.60-eV, and 3.07-eV emission bands which is known to be attribute to silicon-vacancy center, A center, and H3 center, respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.71-75
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• 2001

In this paper, a three-dimensional measuring system of thermoluminescence(TL) spectra based on temperature, wavelength and luminescence intensity was introduced. The system was composed of a spectrometer, temperature control unit for thermal stimulation, photon detector and personal computer for control the entire system. Temperature control was achieved by using feedback to ensure a linear-rise in the sample temperature. Digital multimeter(KEITHLEY 195A) measures the electromotive force of Copper-Constantan thermocouple and then transmits the data to the computer through GPIB card. The computer converts this signal to temperature using electromotive force-temperature table in program, and then control the power supply through the D/A converter. The spectrometer(SPEX 1681) is controlled by CD-2A, which is controlled by the computer through RS-232 communication port. For measuring the luminescence intensity during the heating run, the electrometer(KEITHLEY 617) measures the anode current of photomultiplier tube(HAMAMATSU R928) and transmits the data to computer through the A/D converter. And, we measured and analyzed thermoluminescence of $CaSO_4$ : Dy, P using the system. The measuring range of thermoluminescence spectra was 300K-575K and 300~800 nm, $CaSO_4$ : Dy. P was fabricated by the Yamashita's method in Korea Atomic Energy Research Institute(KAERI) for radiation dosimeter. Thermoluminesce spectra of the $CaSO_4$ : Dy, P consist of two main peak at temperature of $205^{\circ}C$, wavelength 476 nm and 572 nm and with minor ones at 658 nm and 749 nm.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.407.1-407
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• 2001

• Journal of Radiation Protection and Research
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• v.40 no.1
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• pp.46-54
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• 2015

The thermoluminescence (TL) and optically stimulated luminescence (OSL) are commonly used to measure and record the expose of individuals to ionization radiation. Design and performance test results of a newly developed TL and OSL measurement system are presented in this paper. For this purpose, the temperature of the TL material can be controlled precisely in the range of $1{\sim}1.5^{\circ}C$ by using high-frequency (35 kHz) heating system. This high-frequency power supply was made of transformer with ferrite core. For optical stimulation, we have completed an optimal combination of the filters with the arrangement of GG420 filter for filtering the stimulating light source and a UG11 filter at the detecting window (PMT). By using a high luminance blue LED (Luxeon V), sufficient luminous intensity could be obtained for optical stimulation. By using various control boards, the TL/OSL reader device was successfully interfaced with a personal computer. A software based on LabView program (National Instruments, Inc.) was also developed to control the TL/OSL reader system. In this study, a multi-functional TL/OSL dosimeter was developed and the performance testing of the system was carried out to confirm its reliability and reproducibility.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.3
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• pp.165-172
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• 2006

On the MgO single crystals doped artificially with Cr, Cu, Fe we observed thermally stimulated luminescence(TSL) glow curves and spectra, and analyzed them in the temperatures range from at liquid nitrogen temperature(77K) to about 500K after excitation with UV or X-ray irradiation. TSL glow curves obtained from these samples show five peaks at 136.5K, 223.5K, 360K, 390K, 440K, and their estimated activation energies are 0.27eV, 0.63eV, 1.08eV, 1.08eV, 1.19eV, and 1.33eV, respectively. When we measured TSL spectrum at the range of 200nm to 650nm on the MgO single crystals. we also analyzed the peak wavelength which obtained at 345nm, 375nm, and 410nm from measurement of TSL spectrum and described their luminescence mechanisms. TSL spectrum peaks emitted from MgO:Cr, MgO:Cu, and MgO:Fe appear at the wavelengths of 345nm, 360nm, and 375nm, respectively.