• Title/Summary/Keyword: Space radiation

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Directional Radiation Pattern Design Using Structural-Acoustic Coupling (구조-음향 연성현상을 이용한 지향성 방사패턴 설계)

  • Seo, Hee-Seon;Kim, Yang-Hann
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.751-754
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    • 2004
  • This paper presents a design of the directional radiation pattern by using the structural-acoustic interaction. For this purpose, prediction of the pressure distribution of the field points and radiation pattern of the structural-acoustic coupling system is shown. In order to get a strong coupling, coupled system that has a finite space and a semi-infinite space separated by two flexible walls and an opening is selected. A volume interaction can be occurred in structure boundary and a pressure interaction can be happened in the opening boundary. The coupled system is maximized the radiation power on the main axis and minimized the side lobe level.

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HAUSAT-2 SATELLITE RADIATION ENVIRONMENT ANALYSIS AND SOFTWARE RAMMING CODE EDAC IMPLEMENTATION (HAUSAT-2 위성의 방사능 환경해석 및 소프트웨어 HAMMING CODE EDAC의 구현에 관한 연구)

  • Jung, Ji-Wan;Chang, Young-Keun
    • Journal of Astronomy and Space Sciences
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    • v.22 no.4
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    • pp.537-558
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    • 2005
  • This paper addresses the results of HAUSAT-2 radiation environment and effect analyses, including TID and SEE analyses. Trapped proton and electron, solar proton, galactic cosmic ray models were considered for HAUSAT-2 TID radiation environment analysis. TID was analyzed through total dose-depth curve and the radiation tolerance of TID for HAUSAT-2 components was verified by using DMBP method and sectoring analysis. HAUSAT-2 LET spectrum for heavy ion and proton were also analyzed for SEE investigation. SEE(SEU, SEL) analyses were accomplished for MPC860T2B microprocessor and K6X8008T2B memory. It was estimated that several SEUs may occur without SEL during the HAUSAT-2 mission life(2 years). Software Hamming Code EDAC has been implemented to detect and correct the SEU. In this study, all radiation analyses were conducted by using SPENVIS software.

In vitro and in vivo Biological Responses of Proton Irradiation from MC-50 Cyclotron

  • Jung, Uhee;Eom, Hyeon Soo;Jeong, Kwon;Park, Hae-Ran;Jo, Sung-Kee
    • Journal of Radiation Industry
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    • v.6 no.3
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    • pp.223-229
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    • 2012
  • In this study, we investigated the biological damage and stress responses induced by ion beam (proton beam) irradiation as a basis for the development of protective measures against space radiation. We examined the biological effects of proton beam produced by MC-50 cyclotron at KIRAMS on the cultured cells and mice. The proton beam energy used in this study was 34.9 MeV and the absorption dose rate for cells and mice were $0.509Gy\;sec^{-1}$ and $0.65Gy\;sec^{-1}$, respectively. The cell survival rates measured by plating efficiency showed the different sensitivity and dose-relationship between CHO cells and Balb/3T3 cells. HGPRT gene mutation frequency in Balb/3T3 was $15{\times}10^{-6}Gy^{-1}$, which was similar to the reported value of X-ray. When stress signaling proteins were examined in Balb/3T3 cells, $I{\kappa}B-{\alpha}$ decreased markedly whereas p53, phospho-p53, and Rb increased after proton beam irradiation, which implied that the stress signaling pathways were activated by proton beam irradiation. In addition, cellular senescence was induced in IMR-90 cells. In the experiments with C57BL/6 mouse, the immune cells (white blood cells, lymphocytes) in the peripheral blood were greatly reduced following proton beam irradiation whereas red blood cells and platelets showed relatively little change. These results can be utilized as basic data for studying the biological effects of proton beam using MC-50 cyclotron with respect to proton therapy research as well as space radiation research.

Measurement of Comparison to Scattering Dose Space According to the Presence or Absence of Protective Clothing in the X-ray Room (X선 촬영실에서 방호복 유무에 따른 공간산란선량의 측정 비교)

  • Heo, Ye-Ji;Kim, Kyo-Tae;Cho, Chang-Hoon;Kang, Su-Man;Park, Ji-Koon;Kang, Sang-Sik;Noh, Si-Cheul;Jung, Bong-Jae
    • Journal of the Korean Society of Radiology
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    • v.6 no.4
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    • pp.313-320
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    • 2012
  • Current medical institutions with the development of medical technology to the increased demand for health use of radiation equipment is increasing rapidly. Direct radiation from the patient receives the aim of reducing exposure as much as possible is important and the spatial dose of scattered radiation with in the space to engage in reducing healthcare physician, radiation workers and carers need to reduce indirect exposure. X-ray radiation workers and caregivers in the X-ray room to wearing of protective clothing is advised. However Radiation worker sand caregivers of patients with secondary is done, by wearing protective clothing to wear protective clothing because of the weight and discomfort have been neglected. In this study, based on the presence or absence of clothing scattered radiation from space to measure distances, depending on the horizontal and height by measuring the angle of the importance of wearing protective clothing were investigated.

Developments of Space Radiation Dosimeter using Commercial Si Radiation Sensor (범용 실리콘 방사선 센서를 이용한 우주방사선 선량계 개발)

  • Jong-kyu Cheon;Sunghwan Kim
    • Journal of the Korean Society of Radiology
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    • v.17 no.3
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    • pp.367-373
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    • 2023
  • Aircrews and passengers are exposed to radiation from cosmic rays and secondary scattered rays generated by reactions with air or aircraft. For aircrews, radiation safety management is based on the exposure dose calculated using a space-weather environment simulation. However, the exposure dose varies depending on solar activity, altitude, flight path, etc., so measuring by route is more suggestive than the calculation. In this study, we developed an instrument to measure the cosmic radiation dose using a general-purpose Si sensor and a multichannel analyzer. The dose calculation applied the algorithm of CRaTER (Cosmic Ray Telescope for the Effects of Radiation), a space radiation measuring device of NASA. Energy and dose calibration was performed with Cs-137 662 keV gamma rays at a standard calibration facility, and good dose rate dependence was confirmed in the experimental range. Using the instrument, the dose was directly measured on the international line between Dubai and Incheon in May 2023, and it was similar to the result calculated by KREAM (Korean Radiation Exposure Assessment Model for Aviation Route Dose) within 12%. It was confirmed that the dose increased as the altitude and latitude increased, consistent with the calculation results by KREAM. Some limitations require more verification experiments. However, we confirmed it has sufficient utilization potential as a cost-effective measuring instrument for monitoring exposure dose inside or on personal aircraft.

CURRENT TRENDS IN IONIZING RADIATION DETECTION

  • Wehe David K.
    • Nuclear Engineering and Technology
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    • v.38 no.4
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    • pp.311-318
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    • 2006
  • Ionizing radiation is a both a natural and man-made phenomena that plays a major role in contemporary applications. The detection of this radiation has evolved over the past several decades from simple observations to precise measurements in space, time, and energy, even in harsh environmental conditions. Tn this paper, we present a snapshot of the current state-of-the-art in radiation measurement technology, highlighting the major applications and detector developments.

Quality Evaluation of Dried Cooked Rice as Space Food (우주식품 개발을 위한 건조 쌀밥의 품질 평가)

  • Park, Jae-Nam;Song, Beom-Seok;Han, In-Jun;Kim, Jae-Hun;Yoon, Yo-Han;Choi, Jong-Il;Byun, Myung-Woo;Sohn, Hee-Sook;Lee, Ju-Woon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.7
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    • pp.909-913
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    • 2009
  • This study was conducted to investigate the rehydration properties and the sensory quality of sun-dried (SD), hot-air dried (HD), and freeze-dried (FD) cooked rice as space food. Rehydration ratio of HD and FD were significantly higher than those of SD, but there was no significant difference between HD and FD (p<0.05). A cross section of SD showed the smooth surface without any cavities. While HD showed large cavities, many small air cells in FD were observed by a scanning electronic microscope. Stickiness/hardness ratio of HD was similar to that of FD and significantly higher than SD (p<0.05). Also, sensory properties of HD and FD were significantly higher than those of SD, but there were no differences between HD and FD (p<0.05).

A Design of Solar Proton Telescope for Next Generation Small Satellite

  • Sohn, Jongdae;Oh, Suyeon;Yi, Yu;Min, Kyoung-Wook;Lee, Dae-Young;Seon, Jongho
    • Journal of Astronomy and Space Sciences
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    • v.29 no.4
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    • pp.343-349
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    • 2012
  • The solar proton telescope (SPT) is considered as one of the scientific instruments to be installed in instruments for the study of space storm (ISSS) which is determined for next generation small satellite-1 (NEXTSat-1). The SPT is the instrument that acquires the information on energetic particles, especially the energy and flux of proton, according to the solar activity in the space radiation environment. We performed the simulation to determine the specification of the SPT using geometry and tracking 4 (GEANT4). The simulation was performed in the range of 0.6-1,000 MeV considering that the proton, which is to be detected, corresponds to the high energy region according to the solar activity in the space radiation environment. By using aluminum as a blocking material and adjusting the energy detection range, we determined total 7 channels (0.6~5, 5~10, 10~20, 20~35, 35~52, 52~72, and >72 MeV) for the energy range of SPT. In the SPT, the proton energy was distinguished using linear energy transfer to compare with or discriminate from relativistic electron for the channels P1-P3 which are the range of less than 20 MeV, and above those channels, the energy was determined on the basis of whether silicon semiconductor detector (SSD) signal can pass or not. To determine the optimal channel, we performed the conceptual design of payload which uses the SSD. The designed SPT will improve the understanding on the capture and decline of solar energetic particles at the radiation belt by measuring the energetic proton.