• Journal of Radiation Protection and Research
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• 제30권4호
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• pp.231-236
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• 2005

열형광선량계의 TL 소자는 동일한 제조공정에 의해 생산되지만 소자의 반응도가 선량계 별로 편차가 있고, 반복사용 또는 외부로부터의 물리적 자극에 의해 반응도가 조금씩 감소한다. 이러한 반응도 감소를 기준선량제의 평균반응값에 맞추어지도록 보정해 주는 인자가 소자보정이자(ECF)이다. 열형광선량계(TLD)의 ECF 측정절차에 대해 자세히 기술하였으며 319개의 기준선량계, 교정용선량계, 현장선량제의 ECF를 3회 측정하여 평균값을 구하였다. 또한 3회 측정에 대한 %CV를 구하여 ECF 측정값을 검증하였다. 선량계 종류별 용도별로 ECF값의 부포를 구했으며, %CV값의 분포도 나타내었다. 현장선량계는 지난 3년동안 6회정도 사용되었는데 ECF값의 변화가 거의 없었고, 보다 빈번하게 사용된 교정용선량계의 ECF값은 평균 4.7% 증가하였다.

• Journal of Radiation Protection and Research
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• 제48권3호
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• pp.162-166
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• 2023

Background: Assessment of the radiation doses to which workers are exposed can differ depending on the placement of dosimeters on the body. In addition, it is affected by whether the placement is under or over a shielding apron. This study aimed to evaluate the actual positioning of personal dosimeters on the body, with or without shielding aprons, among radiation workers in Korea. Materials and Methods: We analyzed the survey data, which included demographic characteristics, such as sex, age, occupation, work history, and placement of the personal dosimeter being worn, from a cohort study of Korean radiation workers. We assessed the use of personal dosimeters among workers, stratified by sex, age, working period, starting year of work, and occupation. Results and Discussion: Overall, high compliance (89.1% to 99.0%) with the wearing of dosimeters on the chest was observed regardless of workers' characteristics, such as age, sex, occupation, and work history. However, the placement of dosimeters, either under or over the shielding aprons, was inconsistent. Overall, 40.1% of workers wore dosimeters under their aprons, while the others wore dosimeters over their aprons. This inconsistency indicates that radiation doses are possibly measured differently under the same exposure conditions solely owing to variations in the placement of worn dosimeters. Conclusion: Although a lack of uniformity in dosimeter placement when wearing a shielding apron may not cause serious harm in radiation dose management for workers, the development of detailed guidelines for dosimeter placement may improve the accuracy of dose assessment.

• 대한방사선기술학회지:방사선기술과학
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• 제46권2호
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• pp.107-114
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• 2023

The purpose of this study was to compare the basic radiological characteristics of in-house polymer gel and commercially-available gel (BANG^TM) gel dosimeters with a spectro-photometer to use a optical computed tomography (CT) scanner. We investigated the radiological characteristics including dose linearity, absorbance spectrum, dose rate dependency and inter-and intra-reproducibility at wavelengths of 590, 600 and 630 nm. The optimal dose linearities of two gel dosimeters showed R² value of 0.939 and 0.948 at wavelengths of 590 nm and 600 nm, respectively. For two polymer gel dosimeters, there is no peak sensitivity within the range of all wavelengths in absorbance spectrum. For in-house gel dosimeter, the dose rate dependency were within 5% for all wavelengths except for the dose rate of 100 MU/min. For BANG^TM gel dosimeter, the dose rate dependency showed an error range of ±5% for all wavelengths. The inter-and intra-reproducibility of two gel dosimeters were within the range of 2.5%. We have confirmed that the two gel dosimeters was appropriate for use with a optical CT scanner.

• Journal of Radiation Protection and Research
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• 제34권4호
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• pp.165-169
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• 2009

Two dosimeters are provided to radiation workers participating in tasks where high radiation exposure is expected during maintenance at nuclear power plants. At Korean nuclear power plants, two dosimeters are currently provided for tasks where exposure rates exceed 1 mSv/hr, the difference of equivalent dose to specific parts of the body is more than 30% and an exposure of more than 2 mSv is expected in a single task. These conditions for the provisioning of two dosimeters are based on previous field test results, and it is recommended that the dosimeters be worn on the chest and back. It was also found that the workers felt it was more convenient when they wore two dosimeters on chest and back rather than on chest and head. After the application of previous field test results to practice, it was found that the calculated effective dose for workers during radiation work was lower than the maximum dose of chest or back dosimeter by approximately 10%-30%. This performance is regarded not only to meet the international guideline but also to provide convenience for workers during radiation work.

• Journal of Radiation Protection and Research
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• 제41권3호
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• pp.222-228
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• 2016

Background: We are developing a small size dosimeter for dose estimation in particle therapies. The developed dosimeter is an optical fiber based dosimeter mounting an radiation induced luminescence material, such as an OSL or a scintillator, at a tip. These materials generally suffer from the quenching effect under high LET particle irradiation. Materials and Methods: We fabricated two types of the small size dosimeters. They used an OSL material Eu:BaFBr and a BGO scintillator. Carbon ions were irradiated into the fabricated dosimeters at Heavy Ion Medical Accelerator in Chiba (HIMAC). The small size dosimeters were set behind the water equivalent acrylic phantom. Bragg peak was observed by changing the phantom thickness. An ion chamber was also placed near the small size dosimeters as a reference. Results and Discussion: Eu:BaFBr and BGO dosimeters showed a Bragg peak at the same thickness as the ion chamber. Under high LET particle irradiation, the response of the luminescence-based small size dosimeters deteriorated compared with that of the ion chamber due to the quenching effect. We confirmed the luminescence efficiency of Eu:BaFBr and BGO decrease with the LET. The reduction coefficient of luminescence efficiency was different between the BGO and the Eu:BaFBr. The LET can be determined from the luminescence ratio between Eu:BaFBr and BGO, and the dosimeter response can be corrected. Conclusion: We evaluated the LET dependence of the luminescence efficiency of the BGO and Eu:BaFBr as the quenching effect. We propose and discuss the correction of the quenching effect using the signal intensity ratio of the both materials. Although the correction precision is not sufficient, feasibility of the proposed correction method is proved through basic experiments.

• Journal of Radiation Protection and Research
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• 제44권2호
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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.

• International Journal of Computer Science & Network Security
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• 제22권2호
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• pp.15-22
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• 2022

Modern technology drives the world, increasing performance while reducing labor and time expenses. Tanzania Atomic Energy Commission (TAEC) tracks employee's levels of exposure to radiation sources using dosimeters. According to legal compliance, workers wear dosimeters for three months and one month at the workplace. However, TAEC has problems in tracking, issuing and returning dosimeters because the existing tracking is done manually. The study intended to develop a Personal Dose Management System (PDMS) that processes and manages the data collected by dosimeters for easy and accurate records. During the requirements elicitation process, the study looked at the existing system. PDMS' requirement gathering included document reviews, user interviews, and focused group discussions. Development and testing of the system were implemented by applying the evolutionary prototyping technique. The system provides a login interface for system administrators, radiation officers, and Occupational Exposed Workers. The PDMS grants TAEC Staff access to monitor individual exposed workers, prints individual and institutional reports and manages workers' information. The system reminds the users when to return dosimeters to TAEC, generate reports, and facilitates dispatching and receiving dosimeters effectively. PDMS increases efficiency and effectiveness while minimizing workload, paperwork, and inaccurate records. Therefore, based on the results obtained from the system, it is recommended to use the system to improve dosimeter data management at the institution.

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2009년도 춘계 학술발표
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• pp.142-143
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• 2009

See Full Text

• Journal of Radiation Protection and Research
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• 제24권3호
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• pp.143-154
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• 1999

Panasonic UD-809P 알비도 중성자 열형광선량계를 팬텀에 장착시켜 원자력발전소에서 중성자 개인선량당량을 측정하였다. 측정된 판독값으로부터 Panasonic 사의 사용자 매뉴얼에 제시되어 있는 방법을 이용하여 열중성자와 초열중성자 및 속중성자로 인한 개인선량당량을 평가하였다. 그 결과 열중성자 성분의 비율이 높은 원자력발전소에서는 속중성자로 인한 개인선량당량을 적절하게 평가할 수 없는 것으로 확인되었는데, 이는 열중성자로 인한 알비도 성분이 열형광선량계로 재입사 되는 양이 이론적인 값과 상당한 차이가 나기 때문인 것으로 추정되었다. 따라서 원자력발전소와 같이 열중성자 성분의 비율이 높은 조건에서 속중성자로 인한 중성자 개인선량당량을 평가하기 위하여 중성자 성분을 열중성자와 속중성자로 구분한 새로운 중성자 선량계산 알고리즘을 제안하였으며, 각각의 성분에 대한 개인선량당량과 교정인자, 민감도 인자 평가공식을 유도하였다.

• Nuclear Engineering and Technology
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• 제7권3호
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• pp.191-198
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• 1975

혼합 방사선장에서 LiF 열형광 선량계에 의한 중성자 선량측정법에 고나해 연구하였다. 혼합 방사선장에서 중성자선량을 선택적으로 측정하고 평가하기 위해서 $^{6}$LiF 와 $^{7}$LiF 선량계를 속중성자 선량과 열중성자 선량측정에 이용하였다. 개인 방사선 피폭 선량측정에 사용키 위한 보정상수를 유도하였고 중성자와 감마선 선량측정을 위한 그로우곡선을 분석하였다.