• Title, Summary, Keyword: Thermoluminescent dosimeter

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Development of Precise Beta Dosimeter (사고시 대응 정밀 베타선량계 개발)

  • Lee, Won-Keun
    • Proceedings of the KIEE Conference
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    • pp.468-470
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    • 1996
  • The use of thermoluminescent dosimeters (TLDs) for beta dosimetry has been encumbered by the energy-dependent responses of TLDs to beta radiation. This energy-dependent response is due to the low penetrating ability of beta particles. Thus the determination of the beta dose imparted to an exposed TLD chip can be accurately determined only if the energy distribution of beta radiation is correctly accounted for. So precise beta dosimeter used TLD chips place under several aluminum filters of varying thicknesses and developed to correctly determine doses due to radiation fields where the beta energy distribution is unknown.

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Gamma Dosimetry and Clinical Application with $Al_2O_3$ Thermoluminescent Dosimeter ($Al_2O_3$ 열형광(熱螢光) 특성(特性)을 이용(利用)한 감마선(線)의 측정(測定) 및 임상응용(臨床應用))

  • Chu, Seong-Sil;Park, Chang-Yoon
    • Journal of Radiation Protection and Research
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    • v.9 no.1
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    • pp.3-10
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    • 1984
  • The properties of $Al_2O_3$ thermoluminescent phosphor have been observed to apply for gamma dosimetry in vivo. Glow peaks at 380, 420, 490 kelvin temperature with emission in the blue region have been detected and calculated as 1.4 eV the activation energy by means of heat response rising time method. Sensitization and supralinearity in $Al_2O_3$ phosphor could be consistently explained by the deep trap model. Studies of the thermoluminescence growth rate with gamma ray exposure showed linearly to $10^4$ Roentgen and then supralinear rate detected 1.2 power of exposure dose sensitization of $Al_2O_3$ is described five times more than TLD-100 and the fading time is shorter and then tried to apply for gamma dosimetry in vivo.

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Experimental Study with Respect to Dose Characteristic of Glass Dosimeter for Low-Energy by Using Internal Detector of Piranha 657 (Piranha 657의 Internal Detector를 이용한 저에너지에서 유리선량계의 선량 특성에 관한 연구)

  • Son, Jin-Hyun;Min, Jung-Whan;Kim, Hyun-Soo;Lyu, Kwang-Yeul;Lim, Hyun-Soo;Kim, Jung-Min;Jeong, Hoi-Woun
    • Journal of radiological science and technology
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    • v.35 no.2
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    • pp.119-124
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    • 2012
  • Recently, Glass Dosimeter (GD) with thermoluminescent Dosimeter (TLD) are comprehensively used to measure absorbed dose from diagnostic field to therapy field that means from low energy field to high energy field. However, such studies about dose characteristics of GD, such as reproducibility and energy dependency, are mostly results in high energy field. Because characteristic study for measurement devices of radiation dose and radiation detector is performed using 137Cs and 60Co which emit high energy radiations. Thus, this study was evaluated the linearity according to Piranha dose which measured by changing tube voltage (50kV, 80kV and 100kV which are low energy radiations), reproducibility and reproducibility according to delay time using GD. Measurement of radiation dose is performed using internal detector of Piranha 657 which is multi-function QA device (RTI Electronic, Sweden). Condition of measurement was 25mA, 0.02sec, 2.5mAs, SSD of 100 cm and exposure area with $10{\times}10cm^2$. As above method, GD was exposed to radiation. Sixty GDs were divided into three groups (50kV, 80kV, 100kV), then measured. In this study, GD was indicated the linearity in low energy field as high energy existing reported results. The reproducibility and reproducibility according to delay time were acceptable. In this study, we could know that GD can be used to not only measure the high energy field but also low energy field.

Intercomparison Exercise at Harshaw 6600, DVG-02TM, and D-Shuttle Dosimeters for the Individual Monitoring of Ionizing Radiation

  • Kim, Dmitriy Spartakovich;Murayama, Kentaro;Nurtazin, Yernat;Koguchi, Yasuhiro;Kenzhin, Yergazy;Kawamura, Hiroshi
    • Journal of Radiation Protection and Research
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    • v.44 no.2
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    • pp.79-88
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    • 2019
  • Background: The main goal of experiments is to compare various operational and technical characteristics of D-Shuttle semiconductor personal dosimeters of the Japanese company "Chiyoda Technol Corporation" and Harshaw thermoluminescent dosimeters (TLD) manufactured by "Thermo Fisher Scientific" and DTL-02 of the Russian Research and Production Enterprise (RPE) "Doza" by their occupational and calibration exposure at various dose equivalents from 0.5 to 20 mSv of gamma-radiation. Materials and Methods: Besides dosimeters DTL-02, D-Shuttle and Harshaw TLD, there were also used: (1) the primary reference radionuclide source Hopewell Designs IAEA: G10-1-12 with $^{137}Cs$ isotope (an error is not more than 6% and activity is 20 Ci), and (2) the verification device UPGD-2M of RPE "Doza" and installed in the National Center for Expertise and Certification of the Republic of Kazakhstan (Kapchagai, the National Center for Expertise and Certification). Results and Discussion: The main results of researches are the following: (1) TLDs for Harshaw 6600 and DVG-02TM have an approximately equal measurement accuracy of the individual dose equivalents in the range from 0.5 to 20 mSv of gamma-radiation. (2) Advantages of dosimeters for Harshaw 6600 are due to the high measurement productivity and opportunity to indicate the dose on the skin $H_p$(0.07). Advantages of DVG-02TM consist of operation simplicity and lower cost than of Harshaw 6600. (3) D-Shuttles are convenient for use in the current and the operational monitoring of ionizing radiation. Measurement accuracy and 10% linearity of measurements are ensured when D-Shuttle is irradiated with dose equivalents below 1 mSv at the equivalent dose rate not higher than $3mSv{\cdot}hr^{-1}$. This allows using D-Shuttle at a routine technological activity. Conclusion: The obtained results of experiments demonstrate advantages and disadvantages of D-Shuttle semiconductor dosimeters in comparison with two TLD systems of DVG-02TM and Harshaw 6600.

The Effects of Magnetic Field on TLD Glow Curve (자기장이 열형광선량계의 글로우 곡선에 미치는 영향)

  • Je, Jaeyong;Kang, Eunbo
    • Journal of the Korean Society of Radiology
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    • v.7 no.6
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    • pp.415-418
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    • 2013
  • Thermoluminescent dosimeter utilizes the fact that when irradiated specimen is heated up, some part of the absorbed energy is emitted from the specimen as light with longer wavelength. This research aims at analyzing the glow curves of four TLD-100 exposed to a magnetic field and those of other four TLD-100 not exposed to one by treating them with heat and irradiating them, which are commonly used as thermoluminescent dosimeter, in the same condition. As the result of the experiment, regarding the electrons captured by irradiation, some of the electrons of lower traps were combined with positive holes of valence band through the exposure to a magnetic field, and the peak size decreased by 48%. The reduction in the size of the lower traps caused the TLD-100 exposed to a magnetic field to display a low level of dose. In addition, low traps estimated activation energies are 1.6 eV and 1.5 eV.

A study on the effects of scattering dose on eyes and thyroid for panoramagraphy - Focus on TLD and PLD - (파노라마 촬영시 눈과 갑상선에 미치는 표면선량에 관한 연구 - TLD, PLD 중심으로 -)

  • Dong, Kyung-Rae
    • Proceedings of the Korea Contents Association Conference
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    • pp.1118-1123
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    • 2009
  • Ten hospitals from the Gwangju area were used to examine shallow dose to eyes and thyroid from panoramagraphy. Thermoluminescent dosimeter (TLD) and Photoluminescent dosimeter (PLD) were used as measurement devices at each hospital. ICRP 60 and ICRP 73 set standards for acceptability for eyes at 15mSv and thyroid at 1mSv per year. Left eye measures with TLD and PLD resulted in 0.19mSv and 0.24mSv respectively. Right eye measures with TLD and PLD resulted in 0.23mSv and 0.25mSv respectively. Thyroid measures with TLD and PLD resulted in 0.08mSv and 0.25mSv respectively with both measures not exceeding standards for acceptance. There was a significant difference in comparing the left eye and thyroid for TLD and PLD (p<0.01). There was no significant difference with the right eye (p>0.05). The absorbed dose measurements for eyes and thyroid using TLD and PLD in regards to panorama devices at each hospital were within the ICRP 60 recommendations; however, with the possibility of stochastic effect, all dose levels were taken into consideration.

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A Study of the Thermoluminescent Properties of Korean Natural Quartz for Possible Use in Gamma-ray Dosimetry

  • Lee, Hee-Yong;Kim, Hi-Gyu;Lee, Chul
    • Nuclear Engineering and Technology
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    • v.2 no.4
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    • pp.229-239
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    • 1970
  • Various thermoluminescent properties of Korean natural quartz for possible use in ${\gamma}$-ray dosimetry has been studied. If the heating is exactly linear, ${\gamma}$-irradiated radiation sensitive (type 1) $\alpha$-quartz can yield a glow curve of single peak, hence glow peak height could be taken as a ${\gamma}$-dose for its dosimetry. Quartz crystal dosimeter exhibited the linearity of thermoluminescent intensity in the range from about 2$\times$10$^{3}$R to 2$\times$10$^{6}$ R, and also had an advantage of low fading because of the high peak temperature (300$\pm$4$0^{\circ}C$). The pulverized quartz sample having the grain size of 0.3<ø<0.9mm showed the linearity of T. L. intensity in the range from 50R to 2$\times$10$^3$R. Therapeutic application of the pulverized sample on the correct measurement of the absorbed dose in a body region of a cancer patient seems to be successful.

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Determination of Gamma-Ray Depth-Dose Distribution in a Polyethylene Sphere Phantom

  • Ha, Chung-Woo;Jun, Jae-Shik;Park, Chae-Shik
    • Nuclear Engineering and Technology
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    • v.7 no.4
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    • pp.285-293
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    • 1975
  • A result of the study to determine the depth-dose distribution along the central axis of a polyethylene sphere in diameter of 30cm is described. Depth-dose distribution in the polyethylene sphere for broad beam of monoenergetic photons has been experimentally determined with thermoluminescent dosimeter as a cavity dosimeter. The conversion of dose absorbed in the LiF TLD to dose in the surrounding medium was carried out on the basis of Burlin's generalized cavity theory. Presented in graphical forms are the results obtained. The maximum absorbed doses in the sphere were observed at the depth of about 0.3cm and 0.5cm from the surface of the sphere for the gamma-rays of $^{137}$ Cs and $^{60}$ Co, respectively.

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