• Title, Summary, Keyword: thermoluminescence

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Radiation Degradation Detection of LDPE Using Thermoluminescence Method (열발광 특성을 이용한 저밀도 폴리에틸렌의 방사선 열화 검출)

  • Lee, C.;Lee, K.W.;Park, J.N.;Lim, K.J.;Ryu, B.H.;Park, Y.G.;Kang, S.H.;Kim, K.Y.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.43-46
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    • 2001
  • Polymers are widely used as insulating materials at various part of power industry. However, electrical properties of these polymers are easily degraded with their working environments, especially radiation areas. In this research, radiation degradation of low density polyethylene (LDPE) used as cable insulation was evaluated with thermoluminescence characteristics. LDPE was irradiated with gamma ray up to 1000 kGy at a dose rate of 5 kGy/hr in the presence of air at room temperature. Each of the irradiated samples were carried out thermoluminescence analysis as a function of temperature. Interrelationships between thermoluminescence and dielectric characteristics and volume resistivity are investigated as well. The results of thermoluminescence analysis showed that those would be significant factors for evaluation of radiation degradation.

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Detection of Irradiated Potato and Garlic by Thermoluminescence Measurement (Thermoluminescence 측정에 의한 감자와 마늘의 방사선 조사유무 확인)

  • Chung, Hyung-Wook;Kwon, Joong-Ho
    • Korean Journal of Food Science and Technology
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    • v.30 no.2
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    • pp.283-287
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    • 1998
  • Potato and garlic irradiated with gamma ray and electron beam at sprout-inhibition doses, 0.15 and 0.30 kGy were subjected to the detection whether they are irradiated or not by measuring thermoluminescence(TL) for the minerals adhering to the samples. Minerals extracted from the samples showed a high correlation coefficients between absorbed doses and corresponding TL responses. Nonirradiated samples, however, did not exhibit characteristic TL glowcurves. Major glowcurve peaks were observed at 200 to $260^{\circ}C$ in all irradiated samples. TL intensity was proportional to irradiated doses, but it varied with the samples tested even at the same dose. It can be concluded from the results that detection of irradiated potato and garlic is possible by measuring TL for extracted minerals from the unknown samples.

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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.

The Use of Pulsed Photostimulated Luminescence (PPSL) and Thermoluminescence (TL) for the Detection of Irradiated Perilla and Sesame Seeds

  • Yi, Sang-Duk;Woo, Si-Ho;Yang, Jae-Seung
    • Preventive Nutrition and Food Science
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    • v.5 no.3
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    • pp.142-147
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    • 2000
  • To establish a detection method of irradiated perilla and sesame seeds, studies were performed with pulsed photostimulated luminescence (PPSL) and thermoluminescence (TL). The PPSL photon counts of the mineral separated from irradiated sesame and perilla seeds were higher than unirradiated one and exhibited an increase with increasing irradiation dose and mineral content. Also TL intensities of minerals separated from irradiated sesame and perilla seeds increased with increasing irradiation dose. In all samples, detection was possible with shapes and maximum TL temperatures of the second glow curves showing lower regions than those of the first glow curves and correctly classified as irradiated samples. Glow curve ratios of irradiated samples were higher than 0.5. These results suggest that PPSL and TL are applicable methods for the detection of irradiated perilla and sesame seeds.

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Afterglow Properties of LLBO Scintillation Crystal (리튬 루테튬 보레이트 섬광단결정의 잔광 특성)

  • Kim, Sunghwan
    • Journal of Sensor Science and Technology
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    • v.23 no.6
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    • pp.416-419
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    • 2014
  • We grew a $Li_6Lu(BO_3)_3:Ce^{3+}$ single crystal as a new scintillator. And, the scintillation and thermoluminescence properties of the scintillator were determined. The emission spectrum of $Li_6Lu(BO_3)_3:Ce^{3+}$ is located in the range of 370~530 nm, peaking at 416 nm and 439 nm, due to the $5d{\rightarrow}4f$ transition of $Ce^{3+}$ ions. The fluorescence decay time of the crystal is composed two components. The fast component is 34 ns (84%) and the slow component is 125 ns (16%) of the crystal. The afterglow is caused by the electron and hole traps in the crystal lattice. We determined physical parameters of the traps in the crystal. The thermoluminescence trap are composed a trap. The determined activation energy (E) and frequency factor (s) of the TL trap are 1.05 eV and $4.4{\times}10^{10}s^{-1}$, respectively.

A Study on Thermoluminescence of Zinc Oxide (Zinc Oxide의 Thermoluminescence에 대한 연구)

  • 천성순
    • Journal of the Korean Ceramic Society
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    • v.13 no.3
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    • pp.28-36
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    • 1976
  • Zn 산화물을 산과 공기 그리고 헬륨 각각의 분위기에서 열처리 한 후 그 각각에 대한 열광성을 $83^{\circ}~300^{\circ}K$의 온도 범위에서 연구하였다. Zn 산화물의 열광성은 90$0^{\circ}C$ 이상의 온도에서는 산소의 부분압에 의존하며 그 최대강도는 1/T에 비례하였다. 이 성질을 유발한다고 믿어지고 있는 비화학양론적인 결함으 주 요인은 2개의 전자를 trap 하는 산호 이온의 vacancy라고 믿어지고 있다. Trap된 전자의 활성화에너지는 0.13ev였다.

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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.

Identification Characteristics of Irradiated Dried Red Pepper during Storage by Analysis of Thermoluminescence, DNA Comet, and DEFT/APC (Thermoluminescence, DNA Comet 및 DEFT/APC 분석에 의한 방사선처리 건고추의 저장 중 검지 특성)

  • Kim, Byeong-Keun;Kwon, Joong-Ho
    • Korean Journal of Food Science and Technology
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    • v.36 no.6
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    • pp.851-856
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    • 2004
  • Minerals separated from irradiated dried red pepper (whole) at 2.5 kGy or higher showed typical thermoluminescence (TL) glow curves ($TL_1$) at around $150^{\circ}C$, which increased with irradiation dose. The TL ratio ($TL_1/TL_2$) through re-irradiation step at 1 kGy enhanced reliability of TL identification results. DNA comet assay indicated that the intact cell was observed in non-irradiated pepper (seed), while some long tails were found in irradiated ones, showing relationship between irradiation dose and tail length. Log DEPT/APC values increased in proportion to irradiation doses in powdered and whole peppers. Based on overall results, irradiated dried red peppers could be screened using DNA comet assay or log DEFT/APC, and moreover the identification results were verified by TL analysis.

Thermoluminescence Properties of Elpasolite Scintillation Single Crystal (엘파소라이트 섬광형 단결정의 열형광 특성)

  • Kim, Sung-Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.2
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    • pp.492-497
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    • 2012
  • In this paper, we determined the scintillation and thermoluminescence properties of $Cs_2NaCeBr_6$ elpasolite scintillation crystal. The emission spectrum of $Cs_2NaCeBr_6$ is located in the range of 300 ~ 450 nm, peaking at 377 nm and 400 nm. And, the fluorescence decay time of the crystal is composed two components. The fast component is 140 ns (94%), and the slow component is 880 ns (6%) of the crystal. The after-glow is caused by the electron and hole traps in the crystal lattices. We determined thermoluminescence parameters of the traps in the crystal. The determined activation energy(E), kinetic order and frequency factor of the traps are 0.67 eV, 1.71 and $2.51{\times}10^8s^{-1}$ respectively. In this crystal, re-combination rate is more dominant phenomenon than the re-trapping rate.

Identification of Irradiated Granule-Type Ramen Soup Powder by Pulsed Photostimulated Luminescence and Thermoluminescence during Storage

  • Yi, Sang-Duk;Yang, Jae-Seung;Kim, Dong-Woo;Shin, Doo-Ho;Jo, Gab-Yeon;Chang, Kyu-Seob;Oh, Man-Jin
    • Preventive Nutrition and Food Science
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    • v.8 no.1
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    • pp.79-84
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    • 2003
  • This study was carried out to establish a method for determining if granule-type Ramen soup powder has been irradiated. Thermoluminescence (TL) and pulled photostimulated luminescence (PPSL) were used as the detection methods through observed changes of TL and PPSL intensities after storage under differing conditions. PPSL intensities increased with increases in irradiation doses. The threshold level of PPSL was below 412$\pm$58 photon counts regardless of storage conditions (room and darkroom) after 10 months. TL intensities also increased with increasing irradiation doses. The coefficients ($R^2$) of PPSL (0.74~0.94) and TL intensities (0.92~0.58) were very highly correlated with irradiation dose. The PPSL and TL intensities were decreased after 10 months of storage. These results indicate that discrimination of irradiated from non-irradiated granule-type Ramen soup powder is possible using TL and PPSL methods despite the decrease in intensities of TL and PPSL with increasing storage times.