• Title, Summary, Keyword: thermoluminescence (TL)

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Application of Thermoluminescence to Detecting Post-Irradiation of Onion and Garlic (열발광기를 이용한 양파와 마늘의 방사선 조사 여부 검지)

  • ;;Ute Wagner;Georg A. Schreiber
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.27 no.1
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    • pp.63-68
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    • 1998
  • Irradiation can be utilized to inhibit sprouting of onions and garlic. Thermoluminescence(TL) is a potential method to detect post-irradiation of onions and garlic because they are irradiated with soil or dusts on them, from which minerals can be isolated for TL analysis. This study was to determine whether TL can be applied for the detection of post-irradiation of onions and garlic. Onions and garlic produced in Korea were irradiated in the range of 0.01~0.6kGy. Minerals isolated from the samples using sodium polytrungstate solution were used for TL analysis. The onions and garlic irradiated at 0.15kGy or higher could be detected with little errors. Minimum dose for the 2nd glow could be applied since the dose for the 2nd glow did not affect the results. The TL intensities of the temperature ranges of 229~295$^{\circ}C$ and 229~361$^{\circ}C$ and the maximum intensity provided more accurate information for the determination of the post-irradiation of onions and garlic.

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PL and TL behaviors of Ag-doped SnO2 nanoparticles: effects of thermal annealing and Ag concentration

  • Zeferino, R. Sanchez;Pal, U.;Melendrez, R;Flores, M. Barboza
    • Advances in nano research
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    • v.1 no.4
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    • pp.193-202
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    • 2013
  • In this article, we present the effects of Ag doping and after-growth thermal annealing on the photoluminescence (PL) and thermoluminescence (TL) behaviors of $SnO_2$ nanoparticles. $SnO_2$ nanoparticles of 4-7 nm size range containing different Ag contents were synthesized by hydrothermal process. It has been observed that the after-growth thermal annealing process enhances the crystallite size and stabilizes the TL emissions of $SnO_2$ nanostructures. Incorporated Ag probably occupies the interstitial sites of the $SnO_2$ lattice, affecting drastically their emission behaviors on thermal annealing. Both the TL response and dose-linearity of the $SnO_2$ nanoparticles improve on 1.0% Ag doping, and subsequent thermal annealing. However, a higher Ag content causes the formation of Ag clusters, reducing both the TL and PL responses of the nanoparticles.

Observation of Several Detection Factors Derived from Thermoluminescence of Mineral Separated from Irradiated Korean Sesame and Perilla Seeds Stored under Different Storage Conditions

  • Oh, Man-Jin;Yi, Sang-Duk;Yang, Jae-Seung
    • Preventive Nutrition and Food Science
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    • v.7 no.2
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    • pp.188-194
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    • 2002
  • This study was carried out to observe changes in several detection factors derived from thermoluminescence (TL) of minerals separated from irradiated Korean perilla and sesame seeds during storage under normal room and darkroom conditions. The TL intensities of the first glow curves increased from 0 to 5 kGy but only slightly increase from 5 to 10 kGy. Maximum TL temperatures of the first glow curves in all irradiated samples were around 20$0^{\circ}C$, ranging from 150 to 25$0^{\circ}C$. Since the control (0 day of storage) glow curve ratios of G3 and G4, calculated from re-irradiated (1 kGy) sample were over 0.5, detection of irradiation was possible. However, because Gl ratios were below 0.1, they were classified as non-irradiated. There was n unique first glow curve shape that could be clearly seen in all irradiated samples, regardless of storage conditions, that was never seen in non-irradiated samples. In all samples, the maximum TL temperatures and shape of the second glow curve was in a lower temperature range than that of the first glow curve. Therefore, detection of irradiated Korean perilla and sesame seeds was possible fur up to 3 months after irradiation, regardless of storage conditions, by examining several TL detection factors; including TL intensity, glow curve ratios maximum TL temperatures, and the shapes of glow curves.

Thermoluminescence Studies on the High Strength Polyacrylonitrile Fiber (열형광법에 의한 고강력 폴리아크릴로니트릴 섬유의 구조 특성)

  • 이문주;궁판계상
    • Textile Science and Engineering
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    • v.29 no.6
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    • pp.37-43
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    • 1992
  • Thermoluminescence(TL) properties of high strength homopolymer polyacrylonitrile (PAN) fibers were studied to compare those of other ordinary homo- and acrylonitrile(AN) /metbylacrylate(MA) copolymer PAN fibers. The TL properties of PAN fibers was much stronger than in other polymers due to thermo-oxidation induced during heating in TL measurement. That is, thermo-oxidation begins at about 80˚C and remarkably increases with increasing temperature. In this study, the true TL intensity due to detrapping of the second electrons ejected by X-ray exposure was separated from that due to oxidation. The true TL intensity was much smaller in homopolymer PAN fibers than for copolymer PAN fibers. It was suggested that molecular heterogeneity due to copolymerization increases the number of electron trap-sites not only in the amorphous phase but in other phases. Although the difference of TL glowability between high strength and ordinary homopolymer PAN fibers was much smaller than that expected from the difference in fine structure, there was still some difference in the profiles (shape of TL- temperature curves). The TL- and mechanical tan $\delta$-temperature profiles have a high correlation. Homopolymer fibers have smaller intensities for both TL and tan $\delta$ than copolymer fibers.

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Detection of Irradiated Model Food Containing Salt by Thermoluminescence Measurement

  • Chung, Hyung-Wook;Kwon, Joong-Ho
    • Preventive Nutrition and Food Science
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    • v.3 no.1
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    • pp.22-26
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    • 1998
  • Model food containing common salt(NaCl) was subjected to the thermoluminescene(TL) detection whether it is irradiated or not. Salt irradiated with $^60Co$-gamma ray and electron beam exhibited a characteristic TL gowcurve depending on the irradiation dose, showing major peaks at $206^{\circ}C$ and $326^{\circ}C$. The intensity of TL glowcurves was directly proportional to the irradiated doses regardless of irradiation sources at each concentration of salt. A high correlation coefficient was observed for irradiated salt between the irradiation doses and the corresponding TL responses. At the same dose, the intensity of TL glowcurve increased as the concentration of salt increased in the test sample. TL glowcurves of nonirradiated salt and irradiated model food without salt were negligible and similar to a baseline . However, irradiated model food containing salt gave rise to a characteristic TL glowcurve with two major peaks at about $240^{\circ}C$ and $300^{\circ}C$, respectively. The results showed that salt played a role as an internla as well as external indicator in TL measurements, indicating that TL will be applicable to other condiments and spices with salt for their detection whether they are irradiated or not.

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A Study on the Dose Analysis of Pottery Shards by Thermoluminescence Dating Method (TL 연대측정법을 이용한 토기 시편의 선량 분석)

  • Shin, Hyun-Sang
    • Analytical Science and Technology
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    • v.12 no.6
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    • pp.558-564
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    • 1999
  • A method for measuring archaeological dose of Packjae pottery shards using thermoluminescence dosimetry(TLD) has been studied. TL measurement has been achieved using quartz crystals in the size range of 90 to $125{\mu}m$ diameter extracted from the pottery shards. The stable temperature region of the TL glow curve which is devoid of anomalous fading components was identified by the plateau test and found to exist from 265 to $300^{\circ}C$. The archaeological dose of the pottery shards was estimated to be 7.43 Gy using the dose calibration curves obtained from sequential irradiation of $^{137}Cs$ gamma source to the samples and TL measurement of natural samples.

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Identification Characteristics of Irradiated Dried-Spicy Vegetables by Analyzing Photostimulated Luminescence (PSL), Thermoluminescence (TL) and Electron Spin Resonance (ESR) (방사선조사 건조향신채소의 PSL, TL 및 ESR 검지 특성)

  • Kwon Joong-Ho;Kim Mi-Yeung;Kim Byeong-Keun;Lee Jeong-Eun;Kim Dong-Ho;Lee Ju-Woon;Byun Myung-Woo;Lee Chang-Bok
    • Korean Journal of Food Preservation
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    • v.13 no.1
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    • pp.50-54
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    • 2006
  • The identification characteristics of inadiated dried onion and garlic at 1, 4 and 7 kGy were investigated by analyzing their photostimulated luminescence (PSL), thermoluminescence (TL) and electron spin resonance (ESR). The PSL results showed that the photon counts of non-irradiated dried onion were less than 700 (negative) and those of irradiated samples at 1kGy or more were over 5000 (positive), making it possible to discriminate non-irradiated onions from irradiated ones. However, the intermediate counts (700-5000) were observed in irradiated garlic at 1 and 4 kGy, even though positive counts were measured in 7 kGy group. Radiation-induced TL glow curves $(TL_1)$ were measured at $150^{\circ}C$ range in both irradiated onion and garlic samples at 1 kGy or more, which could identify irradiated groups. Furthermore, determination of TL ratios $(TL_1/TL_2)$ for both samples could verify the above results. It was found, however, that ESR spectroscopy was not suitable for the detection of irradiated dried onion and garlic.

An Integrated System for Radioluminescence, Thermoluminescence and Optically Stimulated Luminescence Measurements

  • Park, Chang-Young;Park, Young-Kook;Chung, Ki-Soo;Lee, Jong-Duk;Lee, Jungil;Kim, Jang-Lyul
    • Journal of Radiation Protection and Research
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    • v.43 no.4
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    • pp.160-169
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    • 2018
  • Background: This study aims to develop an integrated optical system that can simultaneously or selectively measure the signals obtained from radioluminescence (RL), thermoluminescence (TL), and optically stimulated luminescence (OSL), which are luminescence phenomena of materials stimulated by radioactivity, heat, and light, respectively. The luminescence mechanism of various materials could be investigated using the glow curves of the luminescence materials. Materials and Methods: RL/TL/OSL integrated measuring system was equipped with a X-ray tube (50 kV, $200{\mu}A$) as an ionizing radiation source to irradiate the sample. The sample substrate was used as a heating source and was also designed to optically stimulate the sample material using various light sources, such as high luminous blue light emitting diode (LED) or laser. The system measured the luminescence intensity versus the amount of irradiation/stimulation on the sample for the purpose of measuring RL, TL and OSL sequentially or by selectively combining them. Optical filters were combined to minimize the interference of the stimulation light in the OSL signal. A long-pass filter (420 nm) was used for 470 nm LED, an ultraviolet-pass filter (260-390 nm) was used for detecting the luminescence of the sample by PM tube. Results and Discussion: The reliability of the system was evaluated using the RL/OSL characteristics of $Al_2O_3:C$ and the RL/TL characteristics of LiF:Mg,Cu,Si, which were used as dosimetry materials. The RL/OSL characteristics of $Al_2O_3:C$ showed relatively linear dose-response characteristics. The glow curve of LiF:Mg,Cu,Si also showed typical RL/OSL characteristics. Conclusion: The reliability of the proposed system was verified by sequentially measuring the RL characteristics of radiation as well as the TL and OSL characteristics by concurrent thermal and optical stimulations. In this study, we developed an integrated measurement system that measures the glow curves of RL/TL/OSL using universal USB-DAQs and the control program.

Detection of Irradiation Treatment for Seasoned-Powdered Foods by Thermoluminescence Measurement (Thermoluminescence 측정에 의한 조미분말식품의 방사선 조사유무 확인)

  • Chung, Hyung-Wook;Kwon, Joong-Ho
    • Korean Journal of Food Science and Technology
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    • v.30 no.3
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    • pp.509-516
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    • 1998
  • Thermoluminescence measurements were applied to the detection of seasoned-powered foods such as shellfish extract powder, seasoned marine products, Ramen soup powder and sardine extract powder whether they are irradiated or not. Correlation coefficients $(R^2)$ between irradiation doses and corresponding TL responses were more than 0.5966 in all samples and 0.9500 in Ramen soup powder. TL threshold value was pre-established for the detection of unknown Ramen soup powders by verifying TL responses with a re-irradiation step. Threshold values were maximum 1.37 for the nonirradiated samples and minimum 6.06 for the 2.5 kGy-irradiated samples. The samples showing values between 1.37 and 6.06 were subjected to a re-irradiation step for their detection, which results were reconfirmed by enumerating the total bacterial load of the detected samples. Pre-established threshold values were successfully applicable to the detection of 167 coded unknown samples, both nonirradiated and irradiated with gamma or electron-beam energy. In the assessment of irradiated doses, three calibration curves were pre-established by plotting TL intensity versus applied doses, of which a quadratic equation was obtained for the potential estimation of irradiated doses with some variations from the real doses.

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Luminescence in SrCl2:Eu2+,Na+ X-ray Storage Phosphor (SrCl2:Eu2+,Na+ X-선 영상저장 형광체의 발광특성)

  • Kim, Sung-Hwan;Kim, Wan;Kang, Hee-Dong;Doh, Sih-Hong;Seo, Hyo-Jin;Kim, Young-Kook;Kim, Do-Sung
    • Korean Journal of Materials Research
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    • v.13 no.6
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    • pp.343-346
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    • 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.