• Title, Summary, Keyword: thermoluminescence dosimeter

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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.

In-vivo Dose verification using MOSFET dosimeter (MOSFET 선량계를 이용한 In-vivo 선량의 확인)

  • Kang, Dae-Gyu;Lee, Kwang-Man
    • Journal of Sensor Science and Technology
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    • v.15 no.2
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    • pp.102-105
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    • 2006
  • In-vivo dosimetry is an essential tool of quality assurance programs in radiotherapy. The most commonly used techniques to verify dose are thermoluminescence dosimeter (TLD) and diode detectors. Metal oxide semiconductor field-effect transistor (MOSFET) has been recently proposed for using in radiation therapy with many advantages. The reproducibility, linearity, isotropy, dose rate dependence of the MOSFET dosimeter were studied and its availability was verified. Consequently the results can be used to improve therapeutic planning procedure and minimize treatment errors in radiotherapy.

Design of a TL Personal Dosimeter Identifiable PA Exposure and Development of Its Dose Evaluation Algorithm (후방피폭선량계측이 가능한 TL 개인선량계의 설계 및 선량평가 알고리즘 개발)

  • Kwon, J.W.;Kim, H.K.;Yang, J.S.;Kim, J.L.;Lee, J.K.
    • Journal of Radiation Protection and Research
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    • v.29 no.3
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    • pp.179-186
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    • 2004
  • A single-dosimeter worn on the anterior surface of body of a worker was found to provide significant underestimation of dose to the worker when radiation comes from behind of the human body. Recently, several researchers suggested that this kind of underestimation can be corrected to a certain extent by using an extra dosimeter on the back. But this multiple dosimetry also has the disadvantages like overestimation lowering work efficiency or cost burden. In this study, a single dosimeter introducing asymmetric filters enabled to identify PA exposure was designed by monte-carlo simulation and experiments and its dose evaluation algorithm for AP-PA mixed radiation field was established. This algorithm was applicable to penetrating radiation which had the effective energy more than 100 keV. Besides, the dosimeter and algorithm in this study were possible to be applied to near PA exposure.

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.

Design of a Badge Filter System for Measurement of Hp(10) with the New Type of TL Dosimeter $CaSO_4:Dy,P$ (신형 TL 선량계인 $CaSO_4:Dy,P$를 이용한 Hp(10) 측정용 배지의 필터체계 설계)

  • Kim, H.K.;Kwon, J.W.;Lee, J.K.;Kim, J.L.
    • Journal of Radiation Protection and Research
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    • v.28 no.2
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    • pp.79-85
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    • 2003
  • This study was intended to estimate Hp(10) recommended by the ICRU using the $CaSO_4:Dy,P$ element developed in the KAERI. For the estimation of Hp(10), TL response should be compensated properly through the energy range using filter materials since $CaSO_4:Dy,P$ is of severe photon energy dependent response. Various experiments and computations using Monte Carlo Code were carried out for designing filter satisfying the performance requirements of the ISO related to TL dosimeter. Under the completed filter, the relative response of $CaSO_4:Dy,P$ showed $0.75{\sim}1.0$ for photons in the range of $20{\sim}662keV$. Especially it was possible to reduce the thickness of front filter and simplify the filter combination with rear filter of larger diameter and to considerably improve angular dependence by introducing taper to the filler.

Development of Algorithm for Evaluation of the Dose with Thermoluminescence Dosimeter (열형광선량계에 의한 선량평가 알고리즘 개발)

  • Song, Myung-Jae;Kim, Hee-Keun;Ha, Chung-Woo;Lee, Tae-Young;Yoon, Suk-Chul
    • Journal of Radiation Protection and Research
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    • v.17 no.2
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    • pp.1-13
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    • 1992
  • The purpose of this study is to develop an algorithm of TLD dose evaluation to meet all requirements stated in ANSI N13. 11-1983. It made the PB-3 TLD of Teledyne Isotopes an object of the development. Personal dosimetry performance testings of the development algorithm have been performed twice through the Atlan-Tech, INC. in accordance with the criteria of testing described in ANSI N13. 11-1983. As ,a result, it is assured that the developed algorithm has complied with all requirements stated in ANSI N13. 11-1983.

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A Study on Characteristic of Glass Dosimeter According to Graded Change of Tube Current (유리선량계의 단계별 관전류량 변화에 따른 특성연구)

  • Son, Jin-Hyun;Kim, Seong-Ho;Mun, Hyun-Jun;Kim, Lyun-Kyun;Son, In-Hwa;Kim, Young-Jun;Min, Jung-Whan;Kim, Ki-Won
    • Journal of radiological science and technology
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    • v.37 no.2
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    • pp.135-141
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    • 2014
  • This study was evaluated the linearity and reproducibility according to dose, and reproducibility according to delay time by changing tube current amount (5 mAs, 10 mAs, 16 mAs, 20 mAs, 25 mAs, 32 mAs respectively, which are low energy radiations) using Glass Dosimeter (GD) and piranha semiconductor dosimeter which are used for measuring exposure dose. Measurements of radiation dose were performed using external detector of piranha 657 which is multi-function QA device (RTI Electronic, Sweden). Conditions of measurement were 80 kVp, SSD 100 cm and exposure region is $10cm{\times}10cm$. Glass dosimeter was exposed to radiation. Twenty-four glass dosimeters were divided into six groups (5 mAs, 10 mAs, 16 mAs, 20 mAs, 25 mAs, 32 mAs respectively), then measured. This study was resulted by measuring the linearity and reproducibility according to change of tube current in low energy field. In dose characteristic of GD, this study could be useful as previous study with regard to dose characteristic according to change of tube voltage in low energy field.

Relative ratio about dose value of thermoluminescence and optical stimulated luminescence dosimeter according to exposed condition in diagnostic radiation (진단방사선의 노출 조건에 따른 열형광선량계와 광자극형광 선량계의 선량값 상대비)

  • Kang, Yeonghan;Kwon, Soonmu;Kim, BooSoon
    • Journal of the Korean Society of Radiology
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    • v.6 no.6
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    • pp.499-505
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    • 2012
  • The purpose of this study was to find out the difference of radiation dose value through energy, exposure number, fluoroscopy time, the number of days of exposed scatter X-ray when TLD and OSLD is used in diagnostic radiology. The difference of value were measured by relative ratio and interval. Energy makes high relative ratio of TLD($1.81{\pm}0.41$) than OSLD($1.40{\pm}0.26$), exposure number makes high of OSLD($1.40{\pm}0.26$) than TLD($2.10{\pm}0.10$). There are no significant differences between relative ratio of TLD and OSLD in fluoroscopy time and the number of days of exposed scatter X-ray. But interval of relative ratio in the number of days of exposed scatter X-ray was narrowed in less 0.2. That means, the measurement of scatter X-ray could more confident in TLD and OSLD than the measurement of direct ray. In conclusion, we have to recognize the relative ratio of TLD and OSLD could be vary depending on exposed condition of radiation. And in some cases, double test of TLD and OSLD get more creditable results of dose value.

A 3-D Measuring System of Thermoluminescence Spectra and Thermoluminescence of CaSO4 : Dy, P (열자극발광 스펙트럼의 3차원 측정 장치와 CaSO4 : Dy, P의 열자극발광)

  • Lee, Jung-Il;Moon, Jung-Hak;Kim, Douk-Hoon
    • Journal of Korean Ophthalmic Optics Society
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    • v.6 no.2
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    • pp.71-75
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    • 2001
  • In this paper, a three-dimensional measuring system of thermoluminescence(TL) spectra based on temperature, wavelength and luminescence intensity was introduced. The system was composed of a spectrometer, temperature control unit for thermal stimulation, photon detector and personal computer for control the entire system. Temperature control was achieved by using feedback to ensure a linear-rise in the sample temperature. Digital multimeter(KEITHLEY 195A) measures the electromotive force of Copper-Constantan thermocouple and then transmits the data to the computer through GPIB card. The computer converts this signal to temperature using electromotive force-temperature table in program, and then control the power supply through the D/A converter. The spectrometer(SPEX 1681) is controlled by CD-2A, which is controlled by the computer through RS-232 communication port. For measuring the luminescence intensity during the heating run, the electrometer(KEITHLEY 617) measures the anode current of photomultiplier tube(HAMAMATSU R928) and transmits the data to computer through the A/D converter. And, we measured and analyzed thermoluminescence of $CaSO_4$ : Dy, P using the system. The measuring range of thermoluminescence spectra was 300K-575K and 300~800 nm, $CaSO_4$ : Dy. P was fabricated by the Yamashita's method in Korea Atomic Energy Research Institute(KAERI) for radiation dosimeter. Thermoluminesce spectra of the $CaSO_4$ : Dy, P consist of two main peak at temperature of $205^{\circ}C$, wavelength 476 nm and 572 nm and with minor ones at 658 nm and 749 nm.

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Anneal Characteristics of LiF:Mg,Cu,Na,Si Teflon TLDs (LiF:Mg,Cu,Na,Si Teflon TLD의 열처리 특성)

  • Nam, Young-Mi;Chung, Woon-Hyuk;Lee, Dae-Won;Kim, Hyun-Ja;Kim, Gi-Dong
    • Journal of Radiation Protection and Research
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    • v.22 no.3
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    • pp.135-141
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    • 1997
  • The study of anneal characteristics is important for TL dosimeter to reuse. To obtain the annealing condition of the recently developed, new TL dosimeter, LiF:Mg,Cu,Na,Si Teflon Tills in a disk type (diameter 4.5 mm, thickness about $90mg/cm^2$), we studied for pre-irradiation annealing, readout procedure and post-readout annealing, in order. The gamma irradiations were carried out with a $^{60}Co$, dose of 0.1 Gy. We have used the method that observe the variation of thermoluminescent(TL) intensity of these Teflon TLDs over repeated cycles by changing both anneal temperature and anneal time with the TLD reader and the oven. There is a 5% loss in sensitivity over the ten repeated readouts by the annealing condition:pre-irradiation annealing at $80^{\circ}C$ for one hour, readout to $280^{\circ}C$ and post-readout annealing at $270^{\circ}C$ for 20 seconds.

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