• Journal of Astronomy and Space Sciences
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• 제32권1호
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• pp.39-44
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• 2015

It is well known that the space radiation dose over the polar route should be carefully considered especially when the space weather shows sudden disturbances such as CME and flares. The National Meteorological Satellite Center (NMSC) and Korea Astronomy and Space Science Institute (KASI) recently established a basis for a space radiation service for the public by developing a space radiation prediction model and heliocentric potential (HCP) prediction model. The HCP value is used as a critical input value of the CARI-6 and CARI-6M programs, which estimate the aviation route dose. The CARI-6/6M is the most widely used and confidential program that is officially provided by the U.S. Federal Aviation Administration (FAA). The HCP value is given one month late in the FAA official webpage, making it difficult to obtain real-time information on the aviation route dose. In order to overcome this limitation regarding time delay, we developed a HCP prediction model based on the sunspot number variation. In this paper, we focus on the purpose and process of our HCP prediction model development. Finally, we find the highest correlation coefficient of 0.9 between the monthly sunspot number and the HCP value with an eight month time shift.

• Journal of Astronomy and Space Sciences
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• 제33권4호
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• pp.279-285
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• 2016

The space radiation dose over air routes including polar routes should be carefully considered, especially when space weather shows sudden disturbances such as coronal mass ejections (CMEs), flares, and accompanying solar energetic particle events. We recently established a heliocentric potential (HCP) prediction model for real-time operation of the CARI-6 and CARI-6M programs. Specifically, the HCP value is used as a critical input value in the CARI-6/6M programs, which estimate the aviation route dose based on the effective dose rate. The CARI-6/6M approach is the most widely used technique, and the programs can be obtained from the U.S. Federal Aviation Administration (FAA). However, HCP values are given at a one month delay on the FAA official webpage, which makes it difficult to obtain real-time information on the aviation route dose. In order to overcome this critical limitation regarding the time delay for space weather customers, we developed a HCP prediction model based on sunspot number variations (Hwang et al. 2015). In this paper, we focus on improvements to our HCP prediction model and update it with neutron monitoring data. We found that the most accurate method to derive the HCP value involves (1) real-time daily sunspot assessments, (2) predictions of the daily HCP by our prediction algorithm, and (3) calculations of the resultant daily effective dose rate. Additionally, we also derived the HCP prediction algorithm in this paper by using ground neutron counts. With the compensation stemming from the use of ground neutron count data, the newly developed HCP prediction model was improved.

• 대한방사선기술학회지:방사선기술과학
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• 제41권4호
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• pp.339-344
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• 2018

Humans received an exposure dose of 2.4 mSv of natural radiation per year, of which the contribution of spacecraft accounts for about 75%. The crew of the aircraft has increased radiation exposure doses based on cosmic radiation safety management regulations There is no reference to air passengers. Therefore, in this study, we measured the radiation exposure dose received in the sky at high altitude during flight, and tried to compare the radiation exposure dose received by ordinary people during flight. We selected 20 sample specimens, including major tourist spots and the capital by continent with direct flights from Incheon International Airport. Using the CARI-6/6M model and the NAIRAS model, which are cosmic radiation prediction models provided at the National Radio Research Institute, we measured the cosmic radiation exposure dose by the selected flight and departure/arrival place. In the case of exposure dose, Beijing was the lowest at $2.87{\mu}Sv$ (NAIRAS) and $2.05{\mu}Sv$ (CARI - 6/6M), New York had the highest at $146.45{\mu}Sv$ (NAIRAS) and $79.42{\mu}Sv$ (CARI - 6/6M). We found that the route using Arctic routes at the same time and distance will receive more exposure dose than other paths. While the dose of cosmic radiation to be received during flight does not have a decisive influence on the human body, because of the greater risk of stochastic effects in the case of frequent flights and in children with high radiation sensitivity Institutional regulation should be prepared for this.

• Journal of Astronomy and Space Sciences
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• 제31권1호
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• pp.25-31
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• 2014

There has been a rapid increase of the concern on the space radiation effect on pilots, crew and passengers at the commercial aircraft altitude (~ 10 km) recently. It is because domestic airline companies, Korean Air and Asiana Airlines have just begun operating the polar routes over the North Pole since 2006 and 2009 respectively. CARI-6 and CARI-6M are commonly used space radiation estimation programs which are provided officially by the U.S. federal aviation administration (FAA). In this paper, the route doses and the annual radiation doses for Korean pilots and cabin crew were estimated by using CARI-6M based on 2012 flight records. Also the modeling concept was developed for our own space radiation estimation program which is composed of GEANT4 and NRLMSIS00 models. The GEANT4 model is used to trace the incident particle transports in the atmosphere and the NRLMSIS00 model is used to get the background atmospheric densities of various neutral atoms at the aircraft altitude. Also presented are the results of simple integration tests of those models and the plan to include the space weather variations through the solar proton event (SPE) prediction model such as UMASEP and the galactic cosmic ray (GCR) prediction model such as Badhwar-O'Neill 2010.

• Journal of Radiation Protection and Research
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• 제29권2호
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• pp.141-150
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• 2004

특정 비행노선에서 우주선에 의한 누적선량을 계산하는 프로그램인 CARI-6를 이용하여 비행고도 우주선 방사선장의 선량률 변화 특성을 분석하고, 국적항공사에서 운행하는 전 국제선 노선에 대한 노선별 우주선 피폭선량을 산출하였다. 산출한 노선별 선량을 항공승무원의 비행스케쥴과 국민의 항공여행 통계에 적용하여 우리나라 항공승무원과 일반 여행객의 우주선에 의한 연간 피폭선량과 집단유효선량을 평가하였다. 평가 결과, 항공승무원의 피폭이 일반인의 선량한도인 연간 1 mSv를 초과하여 평균 2.62mSv로 다른 직업상 피폭을 받는 직군의 선량과 대등한 것으로 평가되었다. 따라서 항공승무원 적군의 우주선 피폭을 일종의 직업상 피폭으로 간주함이 타당함을 확인하였다. 나아가 국민의 해외여행으로 인한 집단선량은 2001년 기준으로 1,100만 명의 출입국자가 총 136man-Sv를 피폭한 것으로 나타났다. ICRP 92에서 양성자와 중성자의 방사선가중치를 변경한 결과를 반영하여 비행고도에서의 우주선 방사선장 정보가 수정될 경우 위의 평가 결과는 보완되어야 한다.

• Journal of Astronomy and Space Sciences
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• 제31권1호
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• pp.33-39
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• 2014

This paper describes an experimental approach to evaluate the effective doses of space radiations at high-altitude by combining the measured data from the Liulin-6K spectrometer loaded onto the air-borne RC-800 cockpit and the calculated data from CARI-6M code developed by FAA. In this paper, 15 exposed dose experiments for the flight missions at a high-altitude above 10 km and 3 experiments at a normal altitude below 4 km were executed over the Korean Peninsula in 2012. The results from the high-altitude flight measurements show a dramatic change in the exposed doses as the altitude increases. The effective dose levels (an average of $15.27{\mu}Sv$) of aircrew at the high-altitude are an order of magnitude larger than those (an average of $0.30{\mu}Sv$) of the normal altitude flight. The comparison was made between the measure dose levels and the calculated dose levels and those were similar each other. It indicates that the annual dose levels of the aircrew boarding RC-800 could be above 1 mSv. These results suggest that a proper procedure to manage the exposed dose of aircrew is required for ROK Air Force.

• Journal of Astronomy and Space Sciences
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• 제39권2호
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• pp.51-57
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• 2022

Cosmic radiation exposure of the flight crews in Korea has been managed by Radiation Safety Management around Living Life Act under Nuclear Safety and Security Commission. However, the domestic flight crews are excluded from the Act because of relatively low route dose exposure compared to that of international flight crews. But we found that the accumulated total annual dose of domestic flight crews is far from negligible because of relatively long total flight time and too many flights. In this study, to suggest the necessity of management of domestic flight crews' radiation exposure, we statistically analyzed domestic flight crew's accumulative annual dose by using cosmic radiation estimation models of the Civil Aviation Research Institute (CARI)-6M, Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS), and Korean Radiation Exposure Assessment Model (KREAM) and compared with in-situ measurements of Liulin-6K LET spectrometer. As a result, the average exposure dose of domestic flight crews was found to be 0.5-0.8 mSv. We also expect that our result might provide the basis to include the domestic flight crews as radiation workers, not just international flight attendants.

• Journal of Astronomy and Space Sciences
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• 제37권4호
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• pp.229-236
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• 2020

There has been increasing necessity of more precise prediction and measurements of aviation radiation in Korea. For our air crew and passengers' radiation safety, we develop our own radiation prediction model of KREAM. In this paper, we validate the KREAM model based on comparison with Liulin observations. During early three months of this year, we perform total 25 experiments to measure aviation radiation exposure using Liulin-6K in commercial flights. We found that KREAM's result is very well consistent with Liulin observation in general. NAIRAS shows mostly higher results than Liulin observation, while CARI-6M shows generally lower results than the observations. The percent error of KREAM compared with Liulin observation is 10.95%. In contrast, the error for NAIRAS is 43.38% and 22.03% for CARI-6M. We found that the increase of the altitude might cause sudden increase in radiation exposure, especially for the polar route. As more comprehensive and complete analysis is required to validate KREAM's reliability to use for the public service, we plan to expand these radiation measurements with Liulin and Tissue Equivalent Proportional Counter (TEPC) in the near future.

• 한국항행학회논문지
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• 제27권6호
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• pp.755-762
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• 2023

우주방사선을 측정을 위해서는 측정장비의 신뢰성이 중요하다. 본연구는 이에 대한 실증으로 현재 우리나라에서 운영되고 있는 우주방사선 실측장비인 Liulin와 TEPC을 항공기에 탑재하여 인천과 로스엔젤레스 구간에서 측정하여 비교하였다. 또한 우주방사선량을 확인하기 위해서는 사전에 예측프로그램을 통한 분석이 필요하므로 FAA가 개발한 CARI-6M과 우리나라의 KREAM 프로그램을 사용하여 예측치를 도출하였다. 검증결과 2개의 장비는 허용수준인 20% 이내로 장비 신뢰도에 문제가 없었다. 또한, 예측프로그램도 각각의 차이가 매우 미세한 것으로 나타났다. 그러나 예측프로그램의 예측값과 실측치와는 큰 차이를 보이는 것으로 분석되었다. 따라서 이에 대한 보정이나 지속적인 연구를 통하여 예측치가 실측치와 유사하도록 프로그램을 보완하는 것이 요구된다.

• Journal of Astronomy and Space Sciences
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• 제27권1호
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• pp.43-54
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• 2010

This study was performed by the policy research project of Ministry of Land, Transport and Maritime Affairs, which title is "Developing safety standards and management of space radiation on the polar route". In this research, total six experiments were performed using Korean commercial flights (B747). Three of those are on the polar route and the other three are on the north pacific route. Space radiation exposure measured on the polar route is the average 84.7 uSv. The simulation result using CARI-6M program gives 84.9 uSv, which is very similar to measured value. For the departure flight using the north pacific route, the measured space radiation is the average 74.4 uSv. It seems that is not so different to use the polar route or not for the return flight because the higher latitude effect causing the increase of space radiation is compensated by the shortened flight time effect causing decreasing space radiation exposure.