Calibration of TEPC for CubeSat Experiment to Measure Space Radiation

Uk-Won Nam,Won-Kee Park,Jaejin Lee,Jeonghyun Pyo,Bong-Kon Moon,Dae-Hee Lee,Sunghwan Kim,Ho Jin,Seongwhan Lee,Jungho Kim,Hisashi Kitamura,Yukio Uchihori 한국우주과학회 2015 Journal of Astronomy and Space Sciences Vol.32 No.2

A newly designed Tissue Equivalent Proportional Counter (TEPC) has been developed for the CubeSat mission, SIGMA (Scientific cubesat with Instruments for Global Magnetic field and rAdiation) to investigate space radiation. In order to test the performance of the TEPC, we have performed heavy ion beam experiments with the Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan. In space, human cells can be exposed to complex radiation sources, such as X-ray, Gamma ray, energetic electrons, protons, neutrons and heavy charged particles in a huge range of energies. These generate much a larger range of Linear Energy Transfer (LET) than on the ground and cause unexpected effects on human cells. In order to measure a large range of LET, from 0.3 to 1,000 keV/μm, we developed a compact TEPC which measures ionized particles produced by collisions between radiation sources and tissue equivalent materials in the detector. By measuring LET spectra, we can easily derive the equivalent dose from the complicated space radiation field. In this HIMAC experiment, we successfully obtained the linearity response for the TEPC with Fe 500 MeV/u and C 290 MeV/u beams and demonstrated the performance of the active radiation detector.

Preliminary Results of Tissue-Equivalent Proportional Counter (TEPC) Dosimeter for Measuring In-Situ Aviation Radiation

Uk-won Nam,Won-kee Park,Junga Hwang,Jongdae Sohn,Bongkon Moon,Sunghwan Kim 한국우주과학회 2020 Journal of Astronomy and Space Sciences Vol.37 No.4

We develop the tissue-equivalent proportional counter (TEPC) type’s space radiation dosimeter to measure in-situ aviation radiation. That was originally developed as a payload of small satellite in the low-earth orbit. This dosimeter is based on a TEPC. It is made of an A-150 tissue-equivalent plastic shell of an internal diameter of 6 cm and a thickness of 0.3 cm. TEPC is filled with pure propane at 13.9 torrs to simulate a cell diameter of 2 μm. And the associated portable and low power electronics are also implemented. The verification experiments have been performed by the calibration experiments at ground level and compared with Liulin observation at aircraft altitude during the flight between Incheon airport (ICN) and John F. Kennedy airport (JFK). We found that the TEPC dosimeter can be used as a monitor for space radiation dosimeter at aviation altitude based on the verification with Liulin observation.

Psychological effects and risk perception after genetic counseling

Shin, Sunghwan,Ryu, Mi Ra,Kwon, Won Kyung,Kim, Suhee,Jang, Ja-Hyun,Kim, Jong-Won Korean Society of Medical Genetics and Genomics 2021 대한의학유전학회지 Vol.18 No.1

Purpose: Demand for genetic counseling on cancer predisposition syndrome is increasing. We evaluated the psychological effect on counselees after genetic counseling at a clinic in a single center. Materials and Methods: We surveyed a total of 72 enrolled participants who visited a genetic counseling clinic at the Samsung Medical Center (SMC). The initial survey was conducted before the first genetic counseling session, and the second survey was conducted after the second genetic counseling session. A total of 43 participants completed both the initial and second surveys. Results: The initial survey of 72 participants indicated higher feelings of guilt in the group with religion, higher depression and anxiety in the group with a diagnosis of self, and higher anxiety in the group on self-referral to the genetic counseling clinic. In the completed survey of 43 participants, overall decreased depression was observed after the second genetic counseling session (P=0.013). Risk perception and anxiety decreased in the group diagnosed with benign variant/variant of uncertain significance (BV/VUS, 25/3) and increased in the group diagnosed with pathogenic variant (PV, 15). Risk perception and anxiety differed between the BV/VUS and PV groups (P<0.001 and P=0.03, respectively). Conclusion: The genetic counseling clinic at the SMC was effective in ameliorating the depression score. Assessment of survey results revealed different depression scores, feelings of guilt and anxiety, and different effects of the genetic counseling clinic, depending on the subgroups. Understanding the needs and psychological characteristics of different groups is necessary for improving genetic counseling services.

Calibration of TEPC for CubeSat Experiment to Measure Space Radiation

Nam, Uk-Won,Park, Won-Kee,Lee, Jaejin,Pyo, Jeonghyun,Moon, Bong-Kon,Lee, Dae-Hee,Kim, Sunghwan,Jin, Ho,Lee, Seongwhan,Kim, Jungho,Kitamura, Hisashi,Uchihori, Yukio The Korean Space Science Society 2015 Journal of Astronomy and Space Sciences Vol.32 No.2

A newly designed Tissue Equivalent Proportional Counter (TEPC) has been developed for the CubeSat mission, SIGMA (Scientific cubesat with Instruments for Global Magnetic field and rAdiation) to investigate space radiation. In order to test the performance of the TEPC, we have performed heavy ion beam experiments with the Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan. In space, human cells can be exposed to complex radiation sources, such as X-ray, Gamma ray, energetic electrons, protons, neutrons and heavy charged particles in a huge range of energies. These generate much a larger range of Linear Energy Transfer (LET) than on the ground and cause unexpected effects on human cells. In order to measure a large range of LET, from 0.3 to $1,000keV/{\mu}m$, we developed a compact TEPC which measures ionized particles produced by collisions between radiation sources and tissue equivalent materials in the detector. By measuring LET spectra, we can easily derive the equivalent dose from the complicated space radiation field. In this HIMAC experiment, we successfully obtained the linearity response for the TEPC with Fe 500 MeV/u and C 290 MeV/u beams and demonstrated the performance of the active radiation detector.

우주방사선측정용 조직등가비례계수관의 교정과 의료분야에서의 응용

김성환(Kim Sunghwan),남욱원(Nam Uk-Won),이재진(Lee Jaejin),표정현(Pyo Jeonghyun),박원기(Park Won-Kee),문봉곤(Moon Bong-Kon),김현수(Yeonsu Kim),백금문(Geum Mun Baek) 한국방사선학회 2014 한국방사선학회 학술대회 논문집 Vol.2014 No.추계

조직등가비례계수기는 우주에서의 복잡한 방사선 환경에서 방사선의 선에너지전이 스펙트럼을 측정하여 등가선량을 측정할 수 있는 검출기이다. 본 연구에서는 국제우주정거장에서 방사선량 모니터링에 활용할 수 있은 조직등가비례계수기를 개발하고 그 특성을 평가하였다. 소형 디지털화된 조직등가비례계수기는 미소선량측정을 위하여 직경 2 μm 크기의 선량을 모사하도록 설계 제작하였다. 개발된 검출기는 한국표준연구원의 252Cf 중성자 표준선원으로 교정하였으며, 채널- 선에너지전이 교정계수는 0.2 keV/μm-CH 이었다 Tissue equivalent proportional counter (TEPC) can measure the LET spectrum and calculate the equivalent dose for the complicated radiation field in space. In this paper, we developed and characterized a TEPC for radiation monitoring in International Space Station (ISS). The compact digital type TEPC which can simulate a 2 μm of the site diameter for micro-dosimetry has been tested with 252Cf neutron standard source in KRISS. The determined calibration factor of channel-LET was about 0.2 keV/μm-CH.

Examination of radiation effects on Cs2LiYCl6:Ce3+ scintillators using a 100 MeV proton beam

Nam Uk-won,윤석원,Park Won-Kee,Pyo Jeonghyun,Sohn Jongdae,Moon Bongkon,예성준,Kim Sunghwan 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.80 No.5

Cs2LiYCl6:Ce3+ scintillator is worthwhile to study, since it has good pulse shape discrimination capability which lead to thermal or fast neutron detection based on the reactions of the constituent elements of Li and Cl. In this study, the effects of proton dose on the scintillation performance of CLYC were measured to check its feasibility for space exploration. A 100 MeV proton beam generated by the Korean Multi-Purpose Accelerator Complex (KOMAC) was used for irradiation of the crystal. The pulse shape discrimination (PSD) for gamma-rays and thermal neutrons as a function of protons dose was used as a standard method for evaluation. After removing gamma-rays background from neutron signal by PSD, we examined the effect of the proton dose on the scintillator based on the electron equivalent energy induced by thermal neutron. When a proton beam was irradiated on the CLYC scintillator at 1 krad, we found a decrease in the light yield by approximately 50% and a rapid increase in the background radiations. Therefore, the detector for gamma-ray measurements was considered unsuitable in high-level proton fields, such as in a low-Earth orbit, owing to the activation problem in CLYC scintillators. However, given that the neutrons can be separated from gamma-rays by the PSD, conducting in situ calibrations using the peaks of the thermal neutron channels up to the maximum dose of the order of several krad through a neutron spectrometer is possible.

Thermal properties of U-7Mo/Al dispersion fuel

Cho, Tae Won,Kim, Yeon Soo,Park, Jong Man,Lee, Kyu Hong,Kim, Sunghwan,Lee, Chong-Tak,Yang, Jae Ho,Oh, Jang Soo,Won, Ju-Jin,Sohn, Dong-Seong ELSEVIER 2017 JOURNAL OF NUCLEAR MATERIALS Vol.496 No.-

<P><B>Abstract</B></P> <P>The thermal diffusivity and heat capacity of U-7Mo/Al and U-7Mo/Al-5Si as functions of U-Mo fuel volume fraction and temperature were measured. The density of the sample was measured at room temperature and estimated using thermal expansion data at elevated temperatures. Using the measured data, the thermal conductivity was obtained as a function of U-Mo volume fraction and temperature. The thermal conductivity of U-7Mo/Al-5Si was found to be lower than that of U-7Mo/Al because of the Si addition to the Al. Due to a lower porosity and reduced interaction between U-Mo and Al in the sample, the thermal conductivity data reported in the present study were higher than those in the literature. The present data were found to be in agreement with the predictions of theoretical models.</P>

Diagnostic Performance of the GENEDIA MTB/NTM Detection Kit for Detecting Mycobacterium tuberculosis and Nontuberculous Mycobacteria With Sputum Specimens

Sunghwan Shin,유인영,Hyang Jin Shim,On-Kyun Kang,Byung Woo Jhun,Won-Jung Koh,허희재,Nam Yong Lee 대한진단검사의학회 2020 Annals of Laboratory Medicine Vol.40 No.2

The GENEDIA MTB/NTM Detection Kit (GENEDIA MTB/NTM; Green Cross Medical Science Corp., Chungbuk, Korea) is a multiplex real-time PCR assay used for differential identification of Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM). While the importance of differential identification of MTB/NTM is recognized, there is limited data on the performance of GENEDIA MTB/NTM assay to date. A total of 687 consecutive sputum specimens were cultured and analyzed with the GENEDIA MTB/NTM and GENEDIA MTB assays. Nineteen specimens (2.8%) were MTBC-positive, and 69 (10.0%) were NTM-positive based on mycobacterial culture. All specimens showed concordant results for MTBC using both assays, with a kappa value of 1.00, overall sensitivity of 63.2% (12/19), and specificity of 100% (668/668). The overall NTM sensitivity and specificity were 23.2% (16/69) and 99.7% (616/618) for GENEDIA MTB/NTM. The association between NTM-positivity using GENEDIA MTB/NTM and the diagnosis of NTM pulmonary disease was not statistically significant. In conclusion, the two real-time PCR assays showed similar diagnostic performance for MTBC detection. However, the sensitivity for NTM detection was lower than that for MTBC detection.

Geriatric Medicine in South Korea: A Stagnant Reality amidst an Aging Population

Sunghwan Ji,Hee-Won Jung,백지연,Il-Young Jang,Eunju Lee 대한노인병학회 2023 Annals of geriatric medicine and research Vol.27 No.4

In the face of an ever-increasing wave of an aging population, this paper provides an update on the current status of geriatric medicine in Korea, comparing it with global initiatives and suggesting future directions. Older adults require a multifaceted approach, addressing not only comorbidity management but also unmet complex medical needs, nutrition, and exercise to prevent functional decline. In this regard, the World Health Organization's Integrated Care for Older People guidelines underscore the importance of patient-centered primary care in preventing a decline in intrinsic capacity. Despite these societal needs and the ongoing aging process, the healthcare system in Korea has yet to show significant movement or a shift toward geriatric medicine, further complicated by the absence of a primary care system. We further explore global efforts in establishing age-integrative patient-centered medical systems in Singapore, Australia, Canada, the United Kingdom, and Japan. Additionally, we review the unmet needs and social issues that Korean society is currently facing, and local efforts by both government and a private tertiary hospital in Korea. In conclusion, considering the current situation, we propose that the framework of geriatric medicine should form the foundation of the future healthcare system.

벼 조생흑찰의 시비조건에 따른 생육 및 안토시아닌 함량변이

오성환,김상열,최원영,서종호,황정동,이휘종,조준현,권영업,남민희,이철원 忠北大學校 農業科學硏究所 2015 農業科學硏究 Vol.31 No.2

Anthocyanin production of black pigmented rice is generally influenced by cultivation environments like transplanting date, cultivation location and fertilization method. This study was carried out to establish an optimum fertilizer application method for production of black pigmented rice with high anthocyanin content. Eight fertilization treatments(NPK, NPK+Si, NPK+Compost, PK, NK, NP, Compost, No Fertilizer) were evaluated with a back pigmented rice cultivar, Josaengheugchal, from 2013 to 2014. Heading date of Josaengheugchal in most fertilization treatments was August 6 to 9 but heading date of NK(P0) treatment was late on August 16. Anthocyanin content was fluctuated between 2013 to 2014. Anthocyanin content of Josaengheugchal in 2014 was higher than that of 2013 because average temperature of ripening stage in 2014 was lower by about 3.2oC than that of 2013. In 2013, anthocyanin content of Josaengheugchal during 30 days after heading(DAH) was decreased by 15.6 mg with increasing average temperature of 1oC. However, temperature effect on anthocyanin content of Josaengheuchal was not observed in 2014 because no significant correlation between average temperature and application treatments was observed. On the other hand, anthocyanin content was significantly influenced by fertilization treatments. Anthocyanin content of Josaengheuchal was highest at the NPK+Compost treatment showing about 17% and 62% higher than NPK, No-Fertilizer treatments, respectively. Total amount of anthocyanin production was also highest with NPK+Compost, higher about 30%, 288% than NPK, No-Fertilizer, respectively.