• Nuclear Engineering and Technology
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• 제54권2호
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• pp.661-665
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• 2022

The 3 MeV proton irradiation effects on SiGe low noise amplifier (LNA) (NXP BGU7005) performance under different voltage supply VCC (0 V, 2.5 V) conditions were firstly experimental studied in this present work. The S parameters including S₁₁, S₂₂, S₂₁, 1 dB compression point and noise figure (NF) of the test samples under different bias voltage supply were measured and compared before and after 3 MeV proton irradiation. The total proton irradiation fluence was 1 × 10¹⁵ protons/cm². The maximum degradation quantities of the gain S₂₁ and NF of the test samples under zero bias are measured respectively 1.6 dB and 1.2 dB. Compared with the samples under 2.5 V bias supply, the maximum degradation of S₂₁ and NF are respectively 1.1 dB and 0.8 dB in the whole frequency band. It is noteworthy that the gain and NF of SiGe LNAs under zero-bias mode suffer enhanced degradation compared with those under normal bias supply. The key influence factors are discussed based on the correlation of the SiGe device and the LNA circuit. Different process of the ionization damage and displacement damage under zero-bias and 2.5 V bias voltage supply contributed to the degradation difference. The underlying physical mechanisms are analyzed and investigated.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.623-625
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• 2022

본 논문에서는 양성자 가속기를 이용하여 5종류의 상용 단일모드 광섬유에 대해서 양성자 조사에 따른 전송손실 특성평가를 수행하였다. 조사 시험에 사용된 양성자 빔은 100 MeV 급의 고에너지를 가지며, 빔 조사면적에 대한 균일도는 10% 이하로 설정하여 시험을 수행하였다. 양성자 조사에 따라서 광섬유 종류(내부 소재, 불순물)의 영향에 따라서 방사선 유입에 의한 광 손실 특성은 큰 차이를 보였다.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.1015-1020
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• 2023

A multi-layer design is applied to mitigate single event effect (SEE) in a 28 nm System-on-Chip (SoC). It depends on asymmetric multiprocessing (AMP), redundancy and system watchdog. Irradiation tests utilized 70 and 90 MeV proton beams to examine its performance through comparative analysis. Via examining SEEs in on-chip memory (OCM), compared with the trial without applying the multi-layer design, the test results demonstrate that the adopted multi-layer design can effectively mitigate SEEs in the SoC.

• 한국인터넷방송통신학회논문지
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• 제24권1호
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• pp.97-101
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• 2024

본 논문에서는 Xilinx 사의 RFSoC FPGA에 대해 양성자 빔 조사 시험 로직 구현과 시험 결과를 제시한다. RFSoC는 FPGA 기능 외에도 CPU, ADC, DAC가 집적화되어 있는 칩으로 소형경량화를 목적으로 둔 방위산업 및 우주 산업에서 주목받고 있는 칩이다. 이러한 칩을 우주 환경에서 사용하려면 방사선 영향에 대한 분석이 필요하며 방사선 경감 대책이 필요하게 되었다. 양성자 조사 시험을 통해 RFSoC의 방사선 영향을 측정할 수 있는 로직을 설계하였다. Memory에 저장된 값을 정상 값과 비교하는 로직을 구현하고 RFSoC에 양성자를 조사하여 Block memory 영역에서 발생하는 SEU를 측정하였다. 다른 영역에서의 SEU 발생을 완화하기 위해 TMR, SEM을 적용하여 설계하였다. 시험 결과를 통해 본 시험 구성에 대해 검증하고 향후 위성용 로직 설계를 검증할 수 있는 환경을 구축하고자 한다.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2823-2834
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• 2023

Austenitic stainless steel welds (ASSWs) of nuclear components undergo aging-related degradations caused by high temperature and neutron radiation. Since irradiation leads to the change of material characteristics, relevant quantification is important for long-term operation, but limitations exist. Although ion irradiation is utilized to emulate neutron irradiation, its penetration depth is too shallow to measure bulk properties. In this study, a systematic approach was suggested to estimate mechanical properties of ion irradiated 308 ASSW. First of all, weld specimens were irradiated by 2 MeV proton to 1 and 10 dpa. Microstructure evolutions due to irradiation in δ-ferrite and austenite phases were characterized and micropillar compression tests were performed. In succession, dislocation density based stress-strain (S-S) relationships and quantification models of irradiation defects were adopted to define phases in finite element analyses. Resultant microscopic S-S curves were compared to verify material parameters. Finally, macroscopic behaviors were calculated by multiscale simulations using real microstructure based representative volume element (RVE). Validity of the approach was verified for the unirradiated specimens such that the estimated S-S curves and 0.2% offset yield strengths (YSs) which was 363.14 MPa were in 10% agreement with test. For irradiated specimens, the estimated YS were 917.41 MPa in 9% agreement.

• 한국항공우주학회지
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• 제32권5호
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• pp.84-90
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• 2004

양성자 가속기를 이용한 지상 실험에 기초하여 인공위성에서 사용할 마이크로프로세서의 SEE 발생률을 예측하였다. 우주 공간의 하전 입자 분포를 AP8, JPL91 그리고 CREME 모델을 사용하여 추정하고, 양성자 가속기를 통한 실험에서 얻어진 단면적 곡선들을 SEE 발생률 예측에 사용하였다. 약 685 km의 저궤도에 대해 고 경사각과 저 경사각이 고려되었다. 계산 결과는 후보 소자에 대한 SEE 발생률이 저 경사각에서는 수용할만한 것이었지만 고 경사각의 경우에는 최악의 조건에서 문제될 수 있음을 보여준다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2295-2297
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• 2003

The major problem encountered in satellite design is EMI (Electro-Magnetic Interference) and EMC (Electro-Magnetic Compatibility). Here, our focus is on the effects of protons on the electronic system. The SEU (Single Event Upset) results from the level change of stored information due to photon radiation and temperature in the space and the nuclear power plant environment. The impact of SEU on PLD (Programmable Logic Devices) technology is most apparent in ROM/SRAM/DRAM devices wherein the state of storage cell can be upset. In this paper, a simple and powerful test techniques is suggested, and the results are presented for the analysis and future reference. The test results are compared with that of JPL test report. In our experiment, the proton radiation facility available at KIRAMS (Korea Institute of Radiological Medical Sciences) has been applied on a commercially available SRAM manufactured by Hynix Semiconductor Company.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.253-253
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• 2010

Rice straw was pretreated with aqueous ammonia in order to enhance enzyme digestibility. Soaking in ammonia aqueous (SAA) was conducted with 15% ammonia, at $60^{\circ}C$. for 24 h. Optimization of both saccharification conditions and enzyme loading of SAA rice straw was carried out. Especially enzyme loading test was performed using statistical method. Moreover proton beam irradiation (PBI) was also performed to overcome the problem which inhibit the enzyme digestibility at 1-25 kGy doses with 45 MeV of beam energy. Optimal condition for enzymatic saccharification was follows; pH 4.8, $50^{\circ}C$, 60 FPU of enzyme activity, 1:4 ratio of celluase and ${\beta}$-glucosidase. Also, optimal doses of PBI on rice straw and SAA-treated rice straw for efficient sugar recovery were found to be 3 kGy, respectively. When saccharification was performed with optimal condition, glucose conversion yield was 89% of theocratical maximum in 48 h, and 3 kGy of PBI was applied to SAA-treated rice straw, approximately 90% of the theoretical glucose yield was obtained in 12 h. The results of X-ray diffractometry (XRD) support the effect of both SAA and PBI on sugar recovery, and scanning electron microscopy (SEM) images unveiled the physical change of the rice straw surface since rugged rice straw surface was observed.

• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1298-1305
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• 2018

The use of System-on-Chip (SoC) solutions in the design of on-board data handling systems is an important step towards further miniaturization in space. However, the Total Ionizing Dose (TID) and Single Event Effects (SEE) characterization of these complex devices present new challenges that are either not fully addressed by current testing guidelines or may result in expensive, cumbersome test configurations. In this paper we report the test setups, procedures and results for TID testing of a SoC microcontroller both using standard $^{60}Co$ and low-energy protons beams. This paper specifically points out the differences in the test methodology and in the challenges between TID testing with proton beam and with the conventional gamma ray irradiation. New test setup and procedures are proposed which are capable of emulating typical mission conditions (clock, bias, software, reprogramming, etc.) while keeping the test setup as simple as possible at the same time.

• 한국항공우주학회지
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• 제34권11호
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• pp.84-91
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• 2006

최근에 인공위성용 전자소자는 우주방사선에 좀 더 강한 소자를 요구되어진다. 왜냐하면, 인공위성의 수명과 기능은 우주방사선으로부터 영향을 받기 때문이다. 또한, 과거에는 부품단위의 우주방사선 시험을 수행하지 않고 유닛 또는 서브시스템 단위의 우주방사선 시험을 수행하였다. 게다가, 발사된 인공위성이 작동오류 상태에 있을 때 그 이유를 분석하기에는 그다지 쉬운 일은 아니다. 따라서, 발사 전 부품 단위 우주방사선 시험을 수행하여 주요 소자에 대한 우주방사선에 의한 영향을 분석 할 필요가 있으며, 지상에서 데이터를 확보할 필요가 있다. 그러므로, 본 논문에서는 모든 전자소자의 기본이라 할 수 있는 금속-산화막 반도체 전계효과 트랜지스터의 총이온화선량에 대한 영향 시험을 수행하기 위한 테스트 베드를 제안한다.