• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.291.1-291
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.443.2-443
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• 2002

• Journal of Sensor Science and Technology
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• v.11 no.5
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• pp.301-308
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• 2002

BaFBr:$Eu^{2+}$ phosphors were prepared, and the thermoluminescence(TL) and photostimulated luminescence(PSL) of the prepared phosphors were measured. Two glow peaks around 352 and 448 K are observed for x-ray irradiated BaFBr:$Eu^{2+}$ phosphors, and the activation energy of the main glow peak(352 K) was about 0.96 eV. The spectral range of the PSL was $350{\sim}450\;nm$, and the activation energy of the trap giving rise to PSL was about 0.98 eV. The activation energy of the traps giving rise to TL is agreed to those giving rise to PSL within experimental error.

• Journal of Food Hygiene and Safety
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• v.16 no.1
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• pp.82-87
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• 2001

A study was performed to establish detection methods by viscometric and pulsed photostimulated luminescence (PPSL) methods for irradiated com powder. Viscosity was determined using a Brookfield DV-rotation viscometer at 3$0^{\circ}C$ and operated at 30, 60, 90, 120, 150, 180, and 210 rpm. All irradiated samples showed a decrease in Viscosity with increasing stirring speeds (rpm) and irradiation doses. Treatments at 1~3 kGy significantly decreased the viscosity. The photon counts of irradiated corn powder were measured by PPSL immediately after irradiation and exhibited an increase with increasing irradiation dose. The photon counts of irradiated com powder almost disappeared with lapse of time in room conditions, but detection of irradiation was still possible after one month at darkroom conditions. Consequently, these results suggest that the detection of irradiated com powder is possible by both viscometric and PPSL methods.

• 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.

• Journal of Radiation Industry
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• v.7 no.1
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• pp.1-5
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• 2013

Photostimulated luminescence (PSL) and thermoluminescence (TL) analyses were applied to identify the cookie molds mixed with 2 mg of 10 kGy-irradiated minerals according to cookie processing methods and sonication time (0~60 min) for mineral separation. PSL analysis showed that photon counts of cookies, dried or baked, ranged intermediate levels between the lower and upper threshold (700~5,000 counts/60 s), thereby showing its unsuitablility for screening of irradiated cookie. The TL glow curve intensities, measured according to mineral separation time (5, 10, 20, 40 and 60 mins) from the cookies using a sonicator, were high enough to identify irradiation status and significantly increased with the time in dried cookies. Those of baked cookies, however, were relatively low and not linearly increased with the time, but still possible to identify them (p<0.05).

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.399-404
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• 2016

The applicability of photostimulated-luminescence (PSL) and thermoluminescence (TL) for the detection of 12 food materials (potato, onion, garlic, dried pumpkin, black mushroom, black soybean, Cheongkukjang powder, sea mustard, pepper powder, Ramyun soup, corn tea, and green tea powder) irradiated with an electron beam, gamma ray, and X ray at a range of 0.15 to 10 kGy was investigated. For PSL, negative results (less than 700 photon counts (PCs)) were observed from non-irradiated foods while the irradiated foods showed intermediate (879 to 2,414 PCs) and/or positive (19,951 to 65,919,035 PCs) values. In all irradiated samples, the maximum peak of the TL glow curve was observed between 150 and $250^{\circ}C$. Our findings demonstrate the successful application of PSL and TL to determine whether food items were irradiated or not. However, there were no significant differences among the radiation sources.

• Journal of Sensor Science and Technology
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• v.11 no.6
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• pp.319-326
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• 2002

$SrCl_2:Eu^{2+}$ phosphors were prepared by the solid phase reaction method, and their photostimulated luminescence(PSL) and photoluminescence(PL) characteristics were investigated. The PSL and PL peak of the $SrCl_2:Eu^{2+}$ phosphors are due to the $5d{\rightarrow}4f$ transition of $Eu^{2+}$ ions in phosphors. The PSL and PL spectrum obtained by the 355nm excitation was observed in $380{\sim}440\;nm$ region with the peak at 407 nm. The dose response of the PSL phosphors were linear within $2.5\;mGy{\sim}200\;mGy$ of 100 kV X-ray. The fading of the phosphors at room temperature was approximately 60% after 20 min.

• Food Science and Preservation
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• v.19 no.1
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• pp.37-46
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• 2012

The identification characteristics of irradiated (0.5, 1, 2, and 4 kGy) brown rice, soybean, and sesame seeds were investigated using photostimulated luminescence (PSL), thermoluminescence (TL), and hydrocarbon analysis during 12-month storage. PSL-based screening was possible for the irradiated soybean and sesame seed samples up to 6 and 12 months, respectively. The TL glow curve shape, intensity, and ratio enabled the clear dose-dependent discrimination of all the non-irradiated and irradiated samples. The TL intensity decreased during storage, but the TL glow curve did not change qualitatively, which provided enough information to confirm the irradiation treatment of the samples over the storage period. Radiation-induced hydrocarbons were found in all the irradiated samples even at 0.5 kGy, throughout the storage period. 8-Heptadecene ($C_{17:1}$) and 1,7-hexadecadiene ($C_{16:2}$) originated from oleic acid, and 6,9-heptadecadiene ($C_{17:2}$) and 1,7,10-hexadecatriene ($C_{16:3}$) originated from linoleic acid, can be used as radiation-induced markers in identifying irradiated brown rice, soybean, and sesame seeds.

• Food Science and 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.