• Title, Summary, Keyword: thermoluminescence (TL)

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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.

The Measurement and Analysis of LiF:Mg, Cu, Na, Si TL Material by Thermoluminescence Spectrum (LiF:Mg, Cu, Na, Si TL 물질의 열자극발광스펙트럼 측정 및 분석)

  • Lee, J.I.;Moon, J.H.;Kim, D.H.
    • Journal of Korean Ophthalmic Optics Society
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    • v.6 no.1
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    • pp.149-153
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    • 2001
  • Three-dimensional thermoluminescence(TL) spectra of LiF: Mg, Cu, Na, Si TL material based on temperature, wavelength and intensity were measured and analyzed. The glow curves were obtained by integration of luminescence intensity for wavelength at each temperature, and various trapping parameters related to the trap formation were determined by analyzing these curves. Computerized glow curve deconvolution(CGCD) method which based on general order kinetics(GOK) model were used for the glow curve analysis. The glow curves of LiF:Mg, Cu, Na, Si TL material were deconvoluted to six isolated glow curves which have peak temperature at 333 K, 374 K, 426 K, 466 K, 483 K and 516 K, respectively. The 466 K main glow peak had an activation energy of 2.06 eV and a kinetic order of 1.05. This TL material was also found to have three recombination centers, 1.80 eV, 2.88 eV and 3.27 eV by TL spectra analysis based on Franck-Condon model. It showed that 2.88 eV is the dominant center, followed by 3.27 eV level, and 1.80 eV center is ascertained as emission center of this material even though its very weak emission intensity.

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Monitoring of Commercial Red Pepper Powders for Their Irradiation Status (물리적 확인시험법을 이용한 시판 유통 중인 고춧가루의 방사선 조사여부 판별 모니터링)

  • Jeong, Mi-Seon;Ahn, Jae-Jun;Akram, Kashif;Kim, Gui-Ran;Kim, Hyun-Ku;Kwon, Joong-Ho
    • Korean Journal of Food Science and Technology
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    • v.44 no.6
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    • pp.673-679
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    • 2012
  • Ten commercially available red pepper powders were investigated using photostimulated-luminescence (PSL), thermoluminescence (TL) and electron spin resonance (ESR) analyses to confirm their irradiation status. The application of PSL, TL, and ESR analyses was also confirmed by in-house irradiation. In PSL-based screening, all samples gave negative photon counts (<700 PCs). The PSL calibration dose (1 kGy) showed a low sensitivity of 4 samples, while the others provided reliable screening results. TL glow curves demonstrated maximum peaks after $250^{\circ}C$ for the 6 samples; however 4 samples gave complex TL glow curves with maximum peaks in the range of $185-260^{\circ}C$ (radiation-specific), which could be the effect of an irradiated component in low concentration as the TL ratios of all samples were <0.1. Radiation-specific ESR features were absent in the all commercial samples. Variable irradiation detection properties were found; where the TL analysis showed the possible presence of an irradiated component in 4 samples requiring further monitoring and investigation.

Identification of Irradiated Food Additives by Photostimulated Luminescence (PSL) Method (Photostimulated Luminescence (PSL) 방법에 의한 국내 유통 분말형 식품가공원료의 방사선 조사 여부 모니터링)

  • Yun, Hyejeong;Hur, Jungmu;Yang, Suhyung;Lee, Byoung-Hun;Kwon, Joong-Ho;Kim, Dongho
    • Journal of Radiation Industry
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    • v.2 no.1
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    • pp.27-34
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    • 2008
  • Photostimulated luminescence (PSL), electron spin resonance (ESR) and thermoluminescence (TL) analyses were conducted to detect whether 258 kinds of extracted and powdered forms food additives were irradiated or not. In a view of the PSL results, 9 kinds of the extracted and powdered samples (3.2%) showed over 5,000 photon counts $(60sec)^{-1}$ and these samples were judged to be irradiation-positive. Thirty nine kinds of the samples (15.6%) yielded 700~5,000 photon counts $(60sec)^{-1}$ and these samples were grouped into irradiation-potential, while the samples showed below 700 photon counts $(60sec)^{-1}$ sec were judged to be irradiation-negative. TL glow curves for minerals separated from 5 samples were detected at $150^{\circ}C$ with high intensity. However, TL analysis did not apply to other irradiation-positive and irradiation-potential samples because the minerals for TL detection were not separated from the samples. ESR measurements for irradiation-positive and irradiation-potential samples, judged by PSL detection, showed no specific signals to irradiation. The results indicated that PSL could be applied to identify irradiation treatment of extracted and powdered food additives, while TL was optional and ESR was not suitable for detection extracted and powdered food additives.

Detection of irradiated food using photostimulated luminescence and thermoluminescence (물리적 방법(PSL, TL)을 이용한 선종별 조사처리 식품의 검지 특성)

  • Jung, Yoo-Kyung;Lee, Ji-Yeon;Kang, Tae-Sun;Jo, Cheon-Ho;Lee, Jae-Hwang;Choi, Jang-Duck;Kwon, Ki-Sung
    • 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.

Development of Phosphorus-compound $CaSO_4$ : Dy(KCT-300) TL Pellets

  • Yang, Jeong-Seon;Kim, Doo-Young;Kim, Jang-Lyul;Lee, Jung-ll;Kim, Bong-Whan;Chang, Si-Young;Park, Jae-Woo
    • Nuclear Engineering and Technology
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    • v.34 no.2
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    • pp.142-145
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    • 2002
  • CaSO$_4$:Dy thermoluminescence dosimeter (TLD) is widely used as a personal or environmental dosimeter because of its high sensitivity to radiation. There are many methods to make pellets from the TL phosphorss[l-5]. Sintered pellets were made from a mixture of CaSO$_4$:Dy phosphor and Teflon powder is the most common method. But this method has disadvantage that CaSO$_4$:Dy pellet does not have very high sensitivity because of large amounts of Teflon in Pellets. This Paper described development of a new type of CaSO$_4$:Dy pellets by using P- compounds as a bonding material (KCT-300), and compared the TL sensitivity with that of the commercialized Teledyne CaSO$_4$: Dy pellets. Sensitivity of a new developed KCT-300 shows about 6 times than Teledyne ones, and can be used to measure very low radiation dose.

Luminescence properties and compositions of contaminating inorganic minerals separated from gamma-irradiated fresh and white ginsengs from different areas

  • Ahn, Jae-Jun;Akram, Kashif;Jeong, Mi-Seon;Kwak, Ji-Young;Park, Eun-Joo;Kwon, Joong-Ho
    • Journal of Ginseng Research
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    • v.37 no.4
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    • pp.483-490
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    • 2013
  • Gamma-irradiation (0-7 kGy) of ginseng is permitted in Korea for the purpose of microbial decontamination; with strict labeling, traceability and monitoring requirements. An identification study was conducted to determine the photostimulated-luminescence (PSL) and thermoluminescence (TL) properties of gamma-irradiated fresh and white ginsengs cultivated in different areas. Dose- dependent PSL-based screening was possible for white ginseng samples; however, inappropriate results from non-irradiated fresh ginseng samples were obtained, showing intermediate (700 to 5,000) or positive ($T_2$ >5,000, irradiated) PSL counts due to the abundance of minerals on the surfaces of the samples. TL analysis of separated minerals from all non-irradiated samples gave TL glow curves of low intensity with a maximum peak after $300^{\circ}C$. However, well-defined irradiation-specific (high intensity with a maximum peak at about $200^{\circ}C$) glow curves were observed for all the irradiated samples, regardless of their type and origins. TL ratios (first glow curve /second glow curve) were also determined to confirm the irradiated (>0.1) and non-irradiated (<0.1) results. SEM-EDX (scanning electron microscope-energy dispersive X-ray) and XRD (X-ray diffraction) spectroscopic analyses showed that feldspar and quartz minerals were the main source for the typical radiation-specific luminescence properties.

Physicochemical Quality and Detection Properties of Irradiated Powdered-Soups (감마선 조사된 분말수프의 이화학적 품질과 조사여부 판별특성)

  • Kwak, Ji-Young;An, Yeoung-Eun;Jung, Bo-Yun;Kwon, Joong-Ho
    • Current Research on Agriculture and Life Sciences
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    • v.30 no.2
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    • pp.82-89
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    • 2012
  • Commercial powdered soups, such as potato soup(PS), corn soup(CS), and chicken-herb soup(CHS), were gamma-irradiated at 0, 1, 5 and 10 kGy and subjected to physicochemical evaluation and identification trials by analyzing photostimulated luminescence(PSL), electron spin resonance(ESR), and thermoluminescence(TL). The changes in moisture content and pH of soup samples were negligible upon irradiation. The Hunter's color determinations showed that lightness (L value) decreased and yellowness (b value) increased as the irradiation dose increased in PS sample. The viscosity of irradiated samples was reduced in the order of PS, CS and CHS. The analyses of PSL, ESR and TL were applicable to the identification of irradiated powdered-soups at more than 1 kGy by detecting PSL photon counts/60 sec(over 5000), radiation-induced multicomponents-ESR signal, and typical TL glow curve at $150-250^{\circ}C$.

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Comparison of Photostimulated Luminescence, Thermoluminescence, and Electron Spin Resonance Spectroscopic Analyses on Dried-spices Irradiated by Gamma Ray and Electron Beam (감마선 및 전자선 조사 처리 건조향신료에 대한 광자극발광, 열발광 및 전자스핀공명의 분광학적 분석 비교)

  • Jeong, Jin-Hwa;Ahn, Jae-Jun;Baek, Ji-Yeong;Kim, Hyo-Young;Kwon, Joong-Ho;Jin, Chang-Hyun;Jeong, Il-Yun
    • Korean Journal of Food Science and Technology
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    • v.46 no.2
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    • pp.256-261
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    • 2014
  • This study was conducted to determine the effect of gamma-ray and electron-beam irradiation on dried spices (black pepper, red pepper, parsley, and basil) using the photostimulated luminescence (PSL), thermoluminescence (TL) and electron spin resonance (ESR) methods. The spices were irradiated at 0, 1, 5, and 10 kGy. All non-irradiated spices had photon counts (PCs) less than 700 PCs. The PCs of three irradiated spices (red pepper, parsley, and basil) were clearly distinguishable from those of non-irradiated ones, exhibiting PSL signals higher than 5000 PCs. However, negative PSL counts (<700 PCs) were obtained for most irradiated black pepper, except those irradiated with 5 kGy gamma rays and 10 kGy electron-beams. TL glow curves of the irradiated spices showed a higher peak at $150-250^{\circ}C$. TL ratios were found to be less than 0.1 for non-irradiated spices and higher than 0.1 for irradiated ones. No ESR signal was observed for any irradiated spice except red pepper, which displayed cellulose-based ESR spectra. Therefore, the results suggest that the PSL, TL, and ESR methods are effective detection techniques for dried spices irradiated with electron beams as well as gamma rays.

Fine Structure and Fatigue Resistance in PET Tire Cord Fibers (타이어 코드용 PET섬유의 미세구조와 내피로성(I))

  • 조현옥;김성중;임무산
    • Textile Science and Engineering
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    • v.29 no.1
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    • pp.57-64
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    • 1992
  • Seven experimental poly(ethylene terephthalate) (PET) fibers have been spun and then drawn at different process conditions, i.e., spinning speed and draw ratio, in such a way that the fibers possess different long periods but retain the crystal structure. Wide angle X-ray diffraction, small angle X-ray scattering, and loss modulus measurements have been used to characterize the fine structure of the fibers. The influence of fine structure on the extensional fatigue behavior of the PET fibers has studied by subjecting them to 120~l8Orev/min repeating deformation at 10$^4$~ 10 5 cycles. In order to detect the molecular motion of PET concerned with the extensional fatigue, thermoluminescence(TL) experiments were performed at high temperature region(above room temperature). The high temperature TL intensity decreased with l0$^4$ cycle extension but increased with l05 cyclic extenxion. The extent of changein TL intensity was found to be a function of long period and loss modulus.

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