• Preventive Nutrition and Food Science
• /
• 제9권2호
• /
• pp.133-137
• /
• 2004

This study was carried out to establish a method for the detection of irradiated glutinous rice by measuring pulsed photostimulated luminescence (PPSL) and viscometric properties. Viscosity was determined using a Brookfield DV-III rotation viscometer at 3$0^{\circ}C$ and measured at 30, 60, 90, 120, 150, 180, and 210 rpm. All irradiated samples indicated a decrease in viscosity with increasing stirring speeds (rpm) and irradiation doses. Treatments with 2∼5 kGy significantly decreased the viscosity. The photon counts of the irradiated glutinous rice were measured by PPSL and the photon counts of the non-irradiated and irradiated glutinous rice measured immediately after irradiation exhibited an increase with increasing irradiation dose. The photon counts of irradiated glutinous rice almost disappeared with the lapse of time when stored under normal room conditions, but was still possible to detect after 12 months of darkroom storage. Consequently, these results indicate that the detection of irradiated glutinous rice is possible by both viscometric and PPSL methods.

• Food Science and Biotechnology
• /
• 제18권2호
• /
• pp.374-378
• /
• 2009

Three physical methods, photostimulated luminescence (PSL), thermoluminescence (TL), and electron spin resonance (ESR), have been applied to detect the irradiation treatment for the non- and steamed sesame seed samples. PSL successfully screened the irradiated samples from the non-irradiated control by comparing their photon counts (PCs) with the lower (less than 700 count/60 sec) and upper threshold values (higher than 5,000 count/60 sec). TL signals were still detected in all irradiated samples even after steaming, which was reconfirmed with TL ratios [integrated area of $TL_1$ (the first glow)/$TL_2$ (the second glow)] through re-irradiation step. ESR spectrometry showed that radiation-induced cellulose radicals were detected in all the irradiated samples irrespective of steaming treatment. Identification of the irradiated sesame seeds was possible even after steaming by analyzing PSL, TL, and ESR.

• Preventive Nutrition and Food Science
• /
• 제6권4호
• /
• pp.216-223
• /
• 2001

A study was carried out to examine the effect of sample form and storage conditions on the accumulated PPSL signals. Korean perilla and sesame seeds were tested as whole samples and separated minerals. Radiation-induced PPSL signals of perilla and sesame seeds themselves significantly increased with irradiation dose up to 5 kGy. On the other hand, a slight decrease in the accumulated PPSL signals was shown at 10 kGy. Similar results were also found in separated minerals. The accumulated PPSL signals of irradiated samples decreased with increasing storage periods. The decay rate was higher in 5 or 10 kGy-irradiated samples than in 1 kGy, in room conditions than in darkroom conditions, and in sesame and perilla seeds themselves than in separated minerals. The accumulated PPSL signals of the irradiated samples measured fur 120 s were higher than those measured for 60 s. These results indicated that although the PPSL signal of all samples decreased with increasing the storage time, detection of irradiated samples was still possible after 12 months of storage regardless of sample form and measurement times (60 and 120 s) in both room and darkroom conditions.

• Preventive Nutrition and Food Science
• /
• 제7권2호
• /
• pp.195-200
• /
• 2002

Changes in accumulated pulsed photostimulated luminescene (PPSL) signals were observed after storage, which affected the ability to detect irradiation in black and white peppers. The PPSL curves were accumulated linearly during the 120 s measurement times, and PPSL signals increased according to irradiation doses. Threshold levels of black and white peppers were below 557$\pm$220 and 503$\pm$92 photon counts in 60 s, and below 679$\pm$351 and 812 $\pm$ 648 photon counts in 120 s, respectively. The PPSL signals of black and white peppers linearly increased with irradiation dose up to 5 kGy, but very little from 5~10 kCy. The accumulated PPSL signals of irradiated black and white peppers had higher decay rates when stored in normal room conditions than in a darkroom Detection of irradiation was possible for up to 12 months after irradiation, if the samples were stored in a darkroom.

• 한국재료학회지
• /
• 제13권6호
• /
• pp.343-346
• /
• 2003

Photoluminescence(PL), photostimulated luminescence(PSL) and thermoluminescence(TL) in $SrC1_2$:$Eu^{2+}$ , $Na^{+}$ phosphor powder were measured, and the activation energies(trap depth) of traps associated with TL and PSL were investigated. The PL and PSL in the studied sample is due to the $4f^{6}$ 5d\longrightarrow$4f^{7}$transition of $Eu^{ 2+}$. TL glow curve is single peak, and its peak temperature is about 377.2 K. The PL, PSL and TL emission spectra of the phosphors are located in the range of 380∼440 nm, peaking at 408 nm. The activation energy of the PSL trapping center is 0.78 eV and that of the TL trapping center is 0.79 eV. We, thus, suggest that the trapping centers giving rise to the PSL are identical to those giving rise to the TL.

• 한국식품저장유통학회지
• /
• 제13권1호
• /
• pp.50-54
• /
• 2006

건조 채소류 중 건조 양파 및 마늘에 대하여 감마선 조사(1,4,7kGy)에 따른 검지특성을 photostimulated luminescence(PSL), thermoluminescence(TL) 및 electron spin resonance (ESR)분석에 의해 확인하였다. PSL분석 결과, 건조 양파 시료는 설정된 negative$(\leq1700)$ 및 Positive$(\geq5000)$ 기준에 맞게 비조사군과 조사군의 차이를 쉽게 확인할 수 있었다. 그러나 건조 마늘의 경우 1 및 4 kGy 조사군은 $700\~5000$ 범위의 photon counts (intermediate)를 보였으나 7kGy 조사군에서는 positive한 결과를 나타내었다. 반면, TL 분석 결과에서는 1kGy 이상으로 조사된 두 시료 모두 $150^{\circ}C$ 전후에서 TL glow curve $(TL_1)$를 나타내어 조사 여부의 확인이 가능하였다. 또한 TL ratio $(TL_1/TL_2)$의 측정은 TL 검지결과의 신뢰성을 높여주었다. ESR 분석에서는 두 시료 모두 비 특이적인 signal이 관찰되어 적용이 불가능한 것으로 나타났다.

• 한국식품과학회지
• /
• 제32권2호
• /
• pp.265-270
• /
• 2000

국내에서 살균, 살충의 목적으로 7kGy의 감마선이 허가된 백삼분말을 대상으로 $0{\sim}15\;kGy$의 전자선을 조사하고 screening을 목적으로 한 PSL측정과 신뢰성이 높은 것으로 여겨지는 TL 측정에 의해 방사선 조사여부를 확인하였다. PSL을 측정한 결과 비조사구는 threshold value$(T_1)$인 700보다 낮은 값을 나타내면서 negative로 표시되어 방사선 조사되지 않은 것으로, 2.5kGy이상 조사구는 threshold value $(T_2)$인 5000보다 높은 값을 나타내면서 positive로 표시되어 방사선 조사된 것으로 확인되었다. Density separation 추출법을 이용하여 시료로부터 mineral을 분리하여 TL 측정을 실시함으로써 glow curve가 나타나는 온도범위와 glow curve의 형태를 확인하고 TL ratio를 구한 결과, 방사선 조사되지 않은 시료는 $300^{\circ}C$ 부근에서 glow curve가 나타났고 이들의 intensity 또한 낮게 나타났다. 그러나 방사선 조사구는 $200^{\circ}C$ 부근에서 아주 강한 intensity의 glow curve를 보여주었다. 또한, normalization에 의한 TL ratio는 비조사구에서 0.01, 조사구에서 0.78 이상을 나타내어 방사선 조사여부 확인이 가능하였다.

• 대한방사선기술학회지:방사선기술과학
• /
• 제29권3호
• /
• pp.141-145
• /
• 2006

염화알칼리토금속화합물에 Eu 이온을 첨가하여 $MCl_2:Eu^{2+}$(M = Ca, Sr, Ba) 형광체를 제조하고, 제조된 형광체의 광발광(photoluminescene) 및 광자극발광(photostimulated luminescence ; PSL) 특성을 조사하였다. $MCl_2:Eu^{2+}$(M = Ca, Sr, Ba)형광체의 광발광 및 광자극발광 파장은 주 모체의 양이온의 종류에 따라 조금씩 이동하였다. $CaCl_2:Eu^{2+}$ 형광체의 최적 제조조건은 $Eu^{2+}$ 이온의 농도가 0.5 mol%, 소결온도와 시간은 각각 $745^{\circ}C$, 45분이었으며, 이때 발광파장범위는 $365{\sim}388\;nm$, 피이크파장은 370 및 380 nm이었다. $BaCl_2:Eu^{2+}$ 형광체의 최적 제조조건은 $Eu^{2+}$ 이온의 농도가 0.5 mol%, 소결온도와 시간은 각각 $905^{\circ}C$, 45분이었으며, 이때 발광파장범위는 $370{\sim}460\;nm$, 피이크파장은 398 nm이었다. $SrCl_2:Eu^{2+}$ 형광체의 최적조건은 $Eu^{2+}$ 이온의 농도가 0.5 mol%, 소결온도와 시간은 각각 $840^{\circ}C$, 45분이었으며, 발광파장영역은 $380{\sim}440\;nm$, 피이크파장은 407 nm이었다. $MCl_2:Eu^{2+}$(0.5 mol%)(M = Ba, Sr) 형광체는 약 $0.25{\sim}200\;mGy$까지 선량 범위에서 선형성을 나타내었으며, 상온에서 $SrCl_2:Eu^{2+}$ (0.5 mol%) 및 $BaCl_2:Eu^{2+}$ (0.5mol%) 형광체의 광자극발광 강도는 상온에서 120분간 각각 60%, 40% 감쇠하였다.

• 한국식품과학회지
• /
• 제45권1호
• /
• pp.8-12
• /
• 2013

건어류의 조사처리 여부 확인을 위하여 PSL-TL 체계의 방법으로 분석하였다. 비조사 시료에서는 모두 700 보다 낮은 PCs를 나타내었고 조사된 멸치는 5000 이상의 PCs를 나타내었으나 조사된 대구, 쥐포, 디포리, 갈치는 비 조사 값을 나타내었다. TL분석에 이용되는 광물질을 얻기 위해 비중분리법과 산가수분해법을 이용하였으며, 그 결과 비 조사시료에서는 $250^{\circ}C$ 이상의 범위에서 낮은 intensity와 peak를 나타났으며 조사된 시료에서는 $150-250^{\circ}C$ 범위에서 높은 intensity와 peak를 나타내었다. 그러나 특히, acid hydrolysis 방법으로 미네랄을 분리하였을 때 TL ratio ($TL_1/TL_2$)와 TL glow curve 결과가 보다 정확한 결과를 얻을 수 있었다.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 2001년도 춘계학술발표회요약집
• /
• pp.446.1-446
• /
• 2001