• Title, Summary, Keyword: thermoluminescence (TL)

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A Study on The Fabrication of The Sintering Process and The Thermoluminescence Properties of UV Dose about The Mg2SiO4 Thermoluminescent Phosphors (Mg2SiO4 열형광체의 소결공정과 자외선 선량에 대한 TL 특성에 관한 연구)

  • Kim, Young-KooK;Shon, In-Ho;Kim, Il-Hong;Song, Jae-Heung;Doh, Sih-Hong;Kang, Hee-Dong
    • Korean Journal of Materials Research
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    • v.12 no.11
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    • pp.870-874
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    • 2002
  • $Mg_2$$SiO_4$: Dy, Tb pellets were made by using a sintering process, including pressing and heat treatment. In the present study, the optimum parameters of the sintering for the $Mg_2$$SiO_4$: Dy, Tb pellets obtained such as the pressing pressure, the sintering temperature and the sintering time were in terms of thermoluminescence. Experimental results showed that the main peak of the glow curve for $Mg_2$$SiO_4$: Dy, Tb thermoluminescence dosimeter was clearly correlated with the energy of the UV and with the grain size. The intensity of the TL glow curve increased and its main peak position shifted to lower temperature with increasing UV irradiation time.

Thermoluminescence of $MgCl_2$-Activated LiF Powder (불순물 $MgCl_2$를 첨가한 LiF 분말의 열형광)

  • 이계철;이상수
    • Nuclear Engineering and Technology
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    • v.2 no.4
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    • pp.269-272
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    • 1970
  • Thermoluminescence (TL) from LiF powder of purity 99.98 % was accomplished and this TL intensity showed glow peaks at 12$0^{\circ}C$, 22$0^{\circ}C$ and 30$0^{\circ}C$. Sintered LiF powder which has an activation of 2% proportion by weight of MgC1$_2$show strong increased TL and this characteristic of the glow curve was investigated precisely. LiF which is used in TL dosimetry has been known to have electrons caused by impurities such as Mg, Mn, etc. This experiment shows that Mg, one of the impurities, is definitely diffused through LiF crystals. The effects of sintering time were detected in this glow curve and it was confirmed that MgC1$_2$also has a TL effect.

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The Quality and Thermoluminescence Properties of Dried Pollack during Storage Following Irradiation (방사선 조사와 저장기간에 따른 북어의 품질 및 thermoluminescence 특성)

  • Noh, Jung-Eun;Kwon, Joong-Ho
    • Korean Journal of Food Science and Technology
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    • v.36 no.5
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    • pp.711-716
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    • 2004
  • Gamma irradiation was applied to dried pollack to improve its microbiological quality and evaluate quality stability of irradiated samples. Thermoluminescence (TL) properties of minerals separated from irradiated samples were measured for possible use in identifying irradiation treatment. Dried pollack was packaged in commercial unit (PVC film, 0.06 mm thickness) and stored at $15{\pm}1^{\circ}C$ for 6 months. Samples showed over $10^4\;CFU/g$ in total aerobic bacteria or yeasts&molds, which increased during storage, reaching $10^6-10^7\;CFU/g$ at 3rd month of storage. Irradiation at 3 kGy was effective for improving hygienic quality for 6 months, keeping microbial population under 20 CFU/g. Gamma irradiation at 3 kGy or less did not significantly influence physicochemical quality attributes, such as browning, TBA value, volatile basic nitrogen, trimethylamine, and sensory properties, whereas storage time remarkably induced quality changes of dried pollack. TL analysis was proved suitable for identifying irradiated from non-irradiated samples over 6 months of storage.

Supralinearity of UV Irradiated Magnesium Aluminum Spinel (자외선 조사된 Magnesium Aluminum Spinel의 Supralinearity)

  • Kim, Tae-Kyu
    • 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.

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The Characteristics of Thermoluminescence from $^{137}$ Cs Irradiated Beta-Eucryptite ($^{137}$ Cs으로 조사된 베타-유크립타이트의 열자극발광 특성)

  • 김태규;이병용;박영우;추성실;황정남
    • 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.

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Development of Thermoluminescence and Optical Stimulated Luminescence Measurements System (열자극발광 및 광자극발광 측정장치의 개발)

  • Park, Chang-Young;Chung, Ki-Soo;Lee, Jong-Duk;Chang, In-Su;Lee, Jungil;Kim, Jang-Lyul
    • 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.

Properties of Pulsed Photostimulated Luminescence and Thermoluminescence for Detection of Gamma-Irradiated Teas during Storage

  • Kausar, Tusneem;Kim, Byeong-Keun;Yang, Jae-Seung;Byun, Myung-Woo;Kwon, Joong-Ho
    • Preventive Nutrition and Food Science
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    • v.9 no.3
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    • pp.227-231
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    • 2004
  • Green, black and oolong teas were irradiated by $^{60}$ Co-gamma rays (0~10 kGy) and were investigated for detection of irradiation treatment using pulsed photostimulated luminescence (PPSL) and thermoluminescence (TL) during storage. Teas irradiated at 2.5 kGy or more showed a photon count of greater than 5000 counts/60 sec while the non-irradiated yielded only 650~1000 count/60 sec. Correlation coefficients between irradiation dose and photon counts/60 sec were 0.8951, 0.7934 and 0.9007 for green, black and oolong teas, respectively. The TL glow curves for minerals isolated from the non-irradiated teas were situated at about 30$0^{\circ}C$ with a low intensity, but for irradiated samples were approximately 15$0^{\circ}C$ with a high intensity. The TL ratios (TL$_1$/TL$_2$), calculated from values after initial radiation and then after re-irradiation of the teas, were below 0.1 for the non-irradiated samples and higher than 1.44 for all irradiated samples, enhanced the reliability of the identification results for TL. The signal intensity of PPSL and TL for irradiated teas decreased with the lapse of post-irradiation storage time at room temperature but was still distinguishable from that of the non-irradiated samples even after one year.

Defect center of $Li^{+}$ ion implanted $Al_2O_3$ ($Li^{+}$ 이온 주입된 $Al_2O_3$의 결함 특성)

  • Kim, Tae-Kyu
    • Progress in Medical Physics
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    • v.5 no.2
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    • pp.13-20
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    • 1994
  • The thermoluminescence(TL) glow curves and the optical absorption of $Al_2O_3$ irradiated with ${\gamma}$-ray, electron, and $Li^{+}$ ion followed by electron irradiation have been investigated to determine the relation of TL peak to its defect type. The TL glow curve of $Al_2O_3$ irradiated with ${\gamma}$-ray shows TL peaks at 380 K, 415 K, and 475 K. The UV photobleached TL glow curve of $Al_2O_3$ irradiated with ${\gamma}$-ray shows that the 380 K and 475 K TL peaks completely disappear while the 415 K TL peak still exists. The electron beam induced TL glow curve of $Al_2O_3$ after $Li^{+}$ ion implantation shows that the TL peak at 440 K is enhanced by a factor of 2 over the TL intensity of unimplanted $Al_2O_3$ while the TL peak at 380 K evidently disappears The implanted $Li^{+}$ ions are assumed to form singly charged interstitial cations and then recombine with electron trapped in F centers to produce F+ centers. The 380 K and 475 K TL peaks are proposed to be associated with F center, while the 415 K and 440 K TL peak are connected with F$^{+}$ center.

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Physical Detection Properties of Irradiated Wheat and Corn Treated with Different Radiation Sources (방사선 조사선원에 따른 밀과 옥수수의 물리적 검지 특성)

  • Kim, Gui-Ran;Lee, Ju-Woon;Kim, Jeong-Sook;Kwon, Joong-Ho
    • Korean Journal of Food Preservation
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    • v.16 no.2
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    • pp.211-216
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    • 2009
  • This study determined the photostimulated luminescence(PSL), thermoluminescence(TL), and electron spin resonance(ESR) properties of wheat and corn irradiated with 0-10 kGy of gamma-ray or electron-beam. PSL values of both irradiated grains, regardless of radiation source, were 241-429 photons/sec in nonirradiated samples(negative values, defined as ${\leq}700$ photons/60 sec) and 5,528-40,870 photons/60 sec in irradiated ones(positive values, defined as ${\geq}5,000$ photons/sec), thereby distinguishing irradiated from nonirradiated samples. The TL glow curves($TL_1$) peaked at around $300^{\circ}C$ in nonirradiated samples, but at about $180^{\circ}C$ in irradiated samples, at high intensities, regardless of radiation source. The TL ratios($TL_1/TL_2$) calculated to strengthen $TL_1$ data reliability were less than 0.03 for nonirradiated samples and over 0.20 for irradiated materials, in good agreement with threshold values for nonirradiated(${\leq}0.1$) and irradiated(${\geq}0.1$) samples. ESR analysis was not applicable in identification of irradiated wheat and corn. Electron-beam irradiation resulted in higher PSL and TL signals than did gamma-rays, at the same applied doses.

Detection of Different Ratios of Gamma-irradiated Turmeric by Photostimulated Luminescence and Thermoluminescence (방사선 조사된 터머릭의 혼합비율에 따른 Photostimulated Luminescence 및 Thermoluminescence 분석 특성)

  • Lee, Ji-Ae;Chung, Hyung-Wook;Kwon, Joong-Ho
    • Korean Journal of Food Science and Technology
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    • v.42 no.6
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    • pp.648-652
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    • 2010
  • This study was performed to investigate PSL and TL characteristics for the detection of different ratios of gamma-irradiated turmeric. It was possible to determine PSL and TL of 1- and 10-kGy irradiated turmeric. The TL ratios ($TL_1/TL_2$) of non-irradiated samples were lower than 0.001, while those of irradiated samples were higher than 0.355. In the PSL results, blended samples containing irradiated ingredients showed intermediate values for a 1% blending rate. Furthermore, TL analysis of blended samples seems to offer a promising method for irradiation identification by TL glow curve form and temperature range. The 1- and 10-kGy irradiated samples were able to be detected above a 4% blending rate. However, the TL ratio appeared as a threshold value below 0.1 for irradiated samples. Overall, TL analysis identified 4% blended samples containing gamma-irradiated turmeric.