• Nuclear Engineering and Technology
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• 제49권6호
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• pp.1354-1357
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• 2017

Characterization of special nuclear material may be performed using energy spectroscopy of either the neutron or gamma-ray emissions from the sample. Gamma-ray spectroscopy can be performed relatively easily using high-resolution semiconductors such as high-purity germanium. Neutron spectroscopy, by contrast, is a complex inverse problem. Here, results are presented for $^{252}Cf$ and PuBe energy spectra unfolded using a single EJ309 organic scintillator; excellent agreement is observed with the reference spectra. Neutron energy spectroscopy is also possible using a two-plane detector array, whereby time-of-flight kinematics can be used. With this system, energy spectra can also be obtained as a function of position. Spatial-dependent energy spectra are presented for neutron and gamma-ray sources that are in excellent agreement with expectations.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3401-3408
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• 2023

In this study, we used the Monte Carlo N-Particle program to simulate the gamma-ray spectra obtained from plastic scintillators holes filled with bismuth nanoparticles. We confirmed that the incorporation of bismuth nanoparticles into a plastic scintillator enhances its performance for gamma-ray spectroscopy using the subtraction method. The subtracted energy spectra obtained from the bismuth-nanoparticle-incorporated and the original plastic scintillator exhibit a distinct energy peak that does not appear in the corresponding original spectra. We varied the diameter and depth of the bismuth-filled holes to determine the optimal hole design for gamma-ray spectroscopy using the subtraction method. We evaluated the energy resolutions of the energy peaks in the gamma-ray spectra to estimate the effects of the bismuth nanoparticles and determine their optimum volume in the plastic scintillator. In addition, we calculated the peak-to-total ratio of the energy spectrum to evaluate the energy measuring limit of the bismuth nanoparticle-containing plastic scintillator using the subtraction method.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.1045-1051
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• 2023

In this study, we fabricated a liquid light-guide-based radiation sensor with a LaBr₃:Ce scintillator for remote gamma-ray spectroscopy. We acquired the energy spectra of Cs-137 and Co-60 using the proposed sensor, estimated the energy resolutions of the full energy peaks, and compared the scintillation light output variations. The major peaks of the radionuclides were observed in each result, and the estimated energy resolutions were similar to that of a general NaI(Tl) scintillation detector without a liquid light guide. Moreover, we showed the relationships of energy resolution and analog-to-digital channel regarding the number of photoelectrons produced and confirmed the effects of light guide length on remote gamma-ray spectroscopy. The proposed sensor is expected to be utilized to perform remote gamma-ray spectroscopy for distances of 3 m or more and would find application in many fields of nuclear facilities and industry.

• 분석과학
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• 제16권1호
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• pp.12-24
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• 2003

$^{252}Cf$ 중성자 선원을 이용한 즉발감마선 계측 시스템 (NIPS, Neutron Induced Promp ${\gamma}$-ray Spectroscopy)을 설계 및 구성하기 위하여, 시스템내의 감속제 및 차폐체등의 효과를 시험하고 감마선 바탕값과 Cl을 포함한 시료의 즉발 감마선을 계측하였다. 이를 위한 예비시험으로 한국원자력연구소 내에 있는 TLD 판독용 $^{252}Cf$ 선원을 이용하였으며 즉발감마선은 시스템 내부의 동축형 HPGe (GMX, 60% relative efficiency)과 시스템외부 (약 20m 거리)의 Notebook PC 중성자와 감마선의 바탕값을 측정하고, 바탕값을 최소로 할 수 있는 차폐체의 기하학적 구조를 고안하였다. 감마선 바탕값을 최소화하기 위하여 두 개의 HPGe 검출기를 이용한 감마-감마 동시계측법을 이용하였다. 이 실험 자료를 이용하여 최적의 NIPS 시스템을 구성하였다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(2)
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• pp.464-469
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• 1998

A coincidence gamma-ray spectroscopy method was applied to reduce the background radioactivity for measuring the activity of radioisotopes in a sample in the presence of environmental natural radioactivity. A HPGe detector was used for the coincident spectrum as a main detector and a NaI(Tl) scintillation detector for gating purposes as an associated detector. For coincidence spectroscopy the whole energy spectrum of associated detector was used instead of gate signals. The coincident events obtained from the gating spectrum was evaluated by a coincidence computer program in this study instead of timing circuit. In this work, the background of detection environment was reduced to factor 100 and peaks to be determined was reduced to factor 30 using the coincidence gamma-ray spectroscopy.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2002년도 강연요지집
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• pp.97-117
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• 2002

A chemoinfometrical method for quantitative determination of crystal content of indomethacin (IMC) polymorphs based on fourie-transformed near-infrared (FT-NIR) spectroscopy was established. A direct comparison of the data with the ones collected from using the conventional powder X-ray diffraction method was performed. Pure $\alpha$ and ${\gamma}$ forms of IMC were prepared using published methods. Powder X-ray diffraction profiles and NIR spectra were recorded for six kinds of standard materials with various content of ${\gamma}$ form IMC. The principal component regression (PCR) analyses were performed based on normalized NIR spectra sets of standard samples of known content of IMC ${\gamma}$ form. A calibration equation was determined to minimize the root mean square error of the prediction. The predicted ${\gamma}$ form content values were reproducible and had a relatively small standard deviation. The values of ${\gamma}$ form content predicted by two methods were in close agreement. The results were indicated that NIR spectroscopy provides for an accurate quantitative analysis of crystallinity in polymorphs compared with the results obtained by conventional powder X-ray diffractometry.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.433-433
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• 2004

Neutron induced prompt gamma-ray spectroscopy (NIPS) system measures the prompt gamma-ray, emitting by the interaction of a neutron with various materials. This system will be of great benefit to scientists worldwide, since it provides the non-destructive measurement of many elements in either solid or liquid wastes. A NIPS facility has been developed in Nuclear Chemistry Research Division, at Korea Atomic Energy Research Institute (KAERI) with the aim of analyzing the major component elements in both aqueous and solid samples.(omitted)

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1955-1963
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• 2021

As the IAEA has applied integrated safeguards and a state level approach to member states, the importance of national inspection has increased. However, the requirements for national inspection for some member states are different from the IAEA safeguards. In particular, the national inspection for the ROK requires on-site U concentration analysis due to a domestic notification. This research proposes an on-site U concentration analysis (OUCA) method for UO₂ pellets using gamma spectroscopy to satisfy the domestic notification requirement. The OUCA method calculates the U concentration of UO₂ pellets using the measured net X-ray counts and declared ²³⁵U enrichment. This research demonstrates the feasibility of the OUCA method using both MCNP simulation and experiment. It simulated and measured the net X-ray counts of different UO₂ pellets with different U concentrations and ²³⁵U enrichments. The simulated and measured net X-ray counts were fitted to polynomials as a function of U concentration and ²³⁵U enrichment. The goodness-of-fit results of both simulation and experiment demonstrated the feasibility of the OUCA method.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 INTERNATIONAL SYMPOSIUM ON SOIL & GROUNDWATER ENVIRONMENT
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• pp.220-221
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• 2005

• Macromolecular Research
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• 제10권6호
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• pp.332-338
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• 2002

The effect of an electron beam and ${\gamma}$-ray irradiation on the curing of epoxy resins was investigated. Diglycidyl ether of bisphenol A (DGEBA) and diglycidyl ether of bisphenol F (DGEBF) as epoxy resin were used. The epoxy resins containing 1.0-3.() wt% of triarylsulphonium hexafluoroantimonate(TASHFA) and triarylsulphonium hexafluorophosphate(TASHFP) as initiator were irradiated under nitrogen at room temperature with different dosage of EB and ${\gamma}$-rays from a Co$^{60}$ u source. The chemical and mechanical characteristics of irradiated epoxy resins were compared after curing of EB and ${\gamma}$-ray irradiation. The thermal properties of cured epoxy were investigated using dynamic mechanical thermal analysis. The chemical structures of cured epoxy were characterized using near infrared spectroscopy. Mechanical properties such as flexural strength, modulus were measured. The gel fraction of DGEBA with ${\gamma}$-ray was higher than that of the epoxy with EB at the same dose. Young's modulus of the sample irradiated by ${\gamma}$-ray is higher than that of sample cured by EB. From the result of strain at yield, it was found that the epoxy cured by ${\gamma}$-ray had a higher stiff property compared with the irradiated by EB.