• Title, Summary, Keyword: 개인선량당량

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Neutron Personal Dose Equivalent Evaluation Using Panasonic UD-809P Type TLD Albedo Dosimeters (Panasonic UD-809P 알비도 열형광선량계를 이용한 중성자 개인선량당량 평가)

  • Shin, Sang-Woon;Son, Joong-Kwon;Jin, Hua
    • Journal of Radiation Protection and Research
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    • v.24 no.3
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    • pp.143-154
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    • 1999
  • Panasonic UD-809P type albedo neutron TL dosimeters mounted on a water phantom were used to measure neutron personal dose equivalent in a Korean nuclear power plant. From the measured TL readings, personal dose equivalents from thermal, epithermal and fast neutrons were evaluated by using a method adopted in a neutron dose calculation algorithm for Panasonic UD-809P type albedo neutron TL dosimeters, which was suggested in a Panasonic TLD System User's Manual. The results showed that personal dose equivalent from fast neutrons could not be adequately evaluated in a field with high thermal neutron fraction to be encountered in a nuclear power plant. This seems to be related to the incomplete incidence of albedo thermal neutrons to the TL dosimeters. In order to evaluate appropriately the personal dose equivalent from fast neutrons in the field condition, new method fer the neutron dose calculation algorithm was suggested. In this new method, neutrons are grouped into thermal neutrons and fast neutrons. For each neutron component, equations for TL response, sensitivity factor, calibration factor and personal dose equivalent were derived.

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Effective Doses in the Radial Gamma Radiation Field near a Point Source: Gender Difference and Deviation from the Personal Dose Equivalent (점선원 감마선장에서 유효선량의 성별차 및 개연선량당량과의 차이)

  • Chang, Jai-Kwon;Lee, Jai-Ki
    • Journal of Radiation Protection and Research
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    • v.22 no.4
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    • pp.299-307
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    • 1997
  • The individual dose equivalent, $H_p$, effective dose, E, and gender specific effective dose, $E^m$ and E$^f$, were evaluated using the male and female phantoms of MIRD type located in the radial gamma radiation field near a point source. The point sources were placed at the distances of 15, 40 and 100 cm in front of the body at different heights. Two radionuclides, $^{137}Cs$ and $^{131}I$, were selected for the illustrative examples. In terms of the gender specific effective doses, $E^f$ is higher than $E^m$ with a few exceptions, e.g. the case where the point source is at the height of reproductive organs, but the differences from the sex- averaged values are not significant enough to justify use of gender specific dose conversion factors for the radial gamma field. The ratios $H_p$/E were in the range of 1 to 3 depending on the source and dosimeter positions when the dosimeter is worn on the front surface of the torso covering from chest to lower abdomen, but varied from 0.34 to 6.5 in extreme cases. When it is assumed that the typical handling procedure of radioactive source material and the typical dosimeter position(on the chest) be respected, the dosimeters calibrated against the broad parallel field appear to provide estimates with acceptable errors for the effective dose of workers exposed to radial broad gamma field around a point source.

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Domestic Intercomparison Study for the Performance of Personnel Dosimeters (개인선량계 성능의 국내 상호비교)

  • Kim, Jang-Lyul;Chang, Si-Young;Kim, Bong-Hwan
    • Journal of Radiation Protection and Research
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    • v.21 no.3
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    • pp.147-153
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    • 1996
  • The Korea Atomic Energy Research Institute(KAERI) conducted a intercomparison study for personnel dosimetry services in Korea to enhance the accuracy and precision of the dosimetry system. Nine types of dosimeters(6 TLD, 3 film badge) from 7 institutions took part in this intercomparison study. Each participant submitted 30 dosimeters including transit control for irradiations. Both TLDs and film badges were irradiated with Cs-137 gamma, Sr/Y-90 beta and 4 X-ray beams in ISO wide series. Four dosimeters were irradiated on phantom with same dose equivalent for each field category. The delivered dose equivalent was in the range of $0.1{\sim}10mSv$. The participants assessed the results of their dosimeter readings in terms of the ICRU operational quantities for personal monitoring, Hp(10) and Hp(0.07). Most participants except 1 dosimeter estimated the delivered dose equivalent with biases less than ${\pm}25%$ for Cs-137 and Sr/Y-90. But for X-rays, the biases exceeded ${\pm}35%$ in some cases bacause the dose evaluation algorithm was based on the ANSI N13.11 X-ray fields which are different from those given by ISO.

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A Evaluation of Effectiveness on Technetium-99m Syringe Shield ($^{99m}Tc$ 주사기 차폐기구의 대한 실효성 평가)

  • Cho, YongIn;Kang, SeSik;Kim, DongHyun;Kim, JungHun
    • Proceedings of the Korea Contents Association Conference
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    • pp.431-432
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    • 2014
  • 본 연구는 핵의학과에서 사용하는 $^{99m}Tc$에서 방출되는 광자에너지에 대하여 거리에 따른 인체에 대한 선량당량을 평가하였다. 그 결과 주사기 차폐기구 유무에 따라 선량당량이 차이를 보였으며, 심부선량은 차폐를 하지 않은 경우 평균 $216.026{\mu}Gy/h$, 1 mm 텅스텐 차폐를 하였을 경우 평균 $4.240{\mu}Gy/h$, 2 mm 텅스텐의 경우 평균 0.124 uGy/h의 선량을 보였다. 이에 따라 주사기 차폐기구를 필수적으로 사용하여야 하며 종사자 개개인의 피폭 관리에 항상 유념하여야 한다. 또한 본 연구결과를 바탕으로 종사자의 피폭 감소 방안에 대한 연구가 지속적으로 이루어 져야할 것으로 생각된다.

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Intercomparison Study of the Neutron Personnel Dosemeters (중성자 개인선량계 상호비교)

  • Kim, Bong-Hwan;Kim, Jang-Lyul;Chang, Si-Young
    • Journal of Radiation Protection and Research
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    • v.23 no.1
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    • pp.49-57
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    • 1998
  • Domestic intercomparison study of the neutron personnel dosemeters was performed for the first time in Korea. Thirteen types of neutron dosemeters from twelve institutions took part in this intercomparison study and the $D_2O$ moderated Cf-252 source of KAERI was used for irradiation. Eight of the fifteen dosemeters submitted by each participant were divided into two groups and each group was irradiated with different doses of the simulated mixed fields of neutron and gamma. The participants assessed their dosemeter reading in terms of the personal dose equivalent, Hp(10), for both neutron and gamma dose. The ratio of the reported dose equivalent to the delivered dose equivalent for comparison between participants ranged from 0.55 to 1.34 for neutron, from 0.54 to 1.32 for gamma and from 0.75 to 1.20 for total dose. This intercomparison results show that all dosemeter processors, especially for neutron category, are able to pass the personnel dosemeter performance test which shall be enforced according to the ordinance of the MOST, No. 96-6.

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Assessment of Occupational Dose to the Staff of Interventional Radiology Using Monte Carlo Simulations (몬테카를로 방법을 이용한 중재방사선시술자에 대한 선량평가)

  • Lim, Young-Khi
    • Journal of Radiation Protection and Research
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    • v.39 no.4
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    • pp.213-217
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    • 2014
  • Medical operations and diagnosis using interventional radiology techniques have been increased. The management and monitoring of occupational radiation exposure to the staff of interventional radiology become important, specially because they stand in close proximity to the patient. The operational radiation protection quantity, Hp(10) which can be obtained from personal dosimeter do not always represent the effective dose to the staff. So, in this study, to estimate the critical organ doses to the staff of interventional radiology, Monte Carlo calculations with mathematical human phantom and dose measurements with personal dosimeters were carried out for the major interventional radiology procedures using C-arm. Results showed that the values of Hp(10) measured by personal dosimeters were higher than critical organ doses which were calculated. And the calculated dose to thyroids was much higher than those of other critical organ doses. For the proper radiation protection of the medical staff of interventional radiology, additional radiation protection for thyroids as well as for whole body shielding like wearing a lead apron should be considered.

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.

Conversion Factors for Calibration of Personnel Dosimeters (개인선량계 교정을 위한 환산인자 계산)

  • Lee, Won-Koo;Lee, Tae-Young;Ha, Chung-Woo
    • Journal of Radiation Protection and Research
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    • v.16 no.1
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    • pp.25-32
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    • 1991
  • MCNP code was used to calculate conversion factor H(d)ma at the depths of 0.07 and 10mm within a water phantom recommended by IAEA and within a PMMA phantom required by the US dosimeter proficiency testing programmes. The calculations were performed for an expanded parrallel beam of monoenergetic photons of perpendicular incidence on one faces of the phantom. The results can be used as conversion factor in calibrating individual dosemeters in terms of the dose equivalent quantities defined directly in the phantom.

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