• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.236-236
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• 2001

• Journal of Radiation Protection and Research
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• v.32 no.4
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• pp.178-183
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• 2007

Neutrons are high LET (linear energy transfer) radiation and cause more damage to the target cells than x-rays or gamma rays. The damage from neutrons is generally considered fatal to a cell and neutrons have a greater tendency to cause cell death through direct interaction on DNA. We performed experiments to measure growth delay ratio and oxygen enhancement ratio (OER) in mouse model system. We inoculated EMT-6 cells to the right hind leg of BALB-c mouse and X-rays and neutron beams were given when the average volume of tumors reached $200-300mm^3$. We irradiated 0, 11, 15.4 Gy of X-ray and 0, 5, 7 Gy of fast neutron beam at normoxic and hypoxic condition. The volume of tumors was measured 3 times per week. In x-ray experiment, growth delay ratio was 1.34 with 11 Gy and 1.33 with 15.4 Gy in normoxic condition compared to in hypoxic condition, respectively. In neutron experiment, growth delay ratio was 0.94 with 5 Gy and 0.98 with 7 Gy, respectively. The OER of neutron beam was 0.97. The neutron beam was more effective than X-ray in the control of hypoxic tumors.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.248-249
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• 2004

하나로는 1995년 2월에 첫 임계(criticality)에 도달한 이후로 핵연료의 조사시험, 동위원소 생산, 중성자 빔을 이용한 연구, 중성자 방사화 분석 등에 활용되고 있다. 하나로에서 발생하는 폐기물은 성상에 따라 기체, 액체, 고체 폐기물로 분류되며, 모두 극저준위 폐기물이다. 고체 폐기물은 방문자 및 종사자들이 원자로실에 출입하여 업무 수행 과정에서 발생하며, 액체 폐기물은 계통의 누설, 보수 작업, 실험 장비 등의 세척으로 발생한다.(중략)

• Nuclear Engineering and Technology
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• v.18 no.2
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• pp.85-91
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• 1986

A single comparator method with its accuracy has been studied for determining multielement by reactor neutron activation analysis. Spectral index at the irradiation position of each sample was determined using two flux monitors of Au and Co, one of which was used as a single comparator. The uncertainties of nuclear data related to the method were investigated for 18 elements and the error of the analytical result due to the uncertainties of nuclear data related is found to be less than 6%. The analytical results of 4 USGS reference samples agree well within 15% deviation with the results evaluated by USGS.

• Journal of the Korean Professional Engineers Association
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• v.34 no.6
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• pp.70-73
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.306.1-306
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• 2002

• Proceedings of the Korean Magnestics Society Conference
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• 2000.05a
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• pp.86-87
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• 2000

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.752-756
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• 1998

산업용 및 의료용으로 사용되는 $^{192}$ Ir 방사선원에 대한 $\psi$선 자기흡수효과인자를 실험을 통하여 구하였다. 이를 위하여 3 mm $\psi$ x 3 mm t, 2.5 mm $\psi$ x 2.5 mm t, 2 mm $\psi$ x 2 mm Ir의 원주형 Ir 표적과 3 mm $\psi$ x 0.25 mm t, 3 mm $\psi$ x 0.1 mm t의 원판형 Ir 표적을 하나로의 PTS(Pneumatic Transport System)조사공에서 중성자 조사하였다. 이온전리함을 사용하여 각 Ir 표적의 방사능을 측정하고 계산에 의해서 구한 생성방사능 값과의 비를 구하는 방법으로 $^{192}$ Ir의 ${\gamma}$선 자기흡수효과인자를 구하였다. 이 값들은 원주형 표적에 대하여 각각 0.614, 0.687, 0.704 였고 원판형 표적에 대하여 각각 0.827, 0.875 였다. 원주형 Ir 표적내부의 중성자 자기흡수효과의 정도를 알아보기 위하여 2.5 mm $\psi$ x 0.25 mm t Ir 표적 10장을 포개어 중성자 방사화시킨 후 각 표적의 방사능을 측정한 결과 가장 바깥쪽 표적의 방사능이 중심부에 위치한 표적보다 약 2배정도 방사화가 많이 일어남을 알 수 있었다. 이번에 구한 ${\gamma}$선 자기흡수효과인자는 향후 산업용 및 의료용으로 사용되는 $^{192}$ Ir 방사선원의 사용자에게 제공되는 최종방사능을 평가하는데 유용하게 사용될 수 있다.

• Korean Journal of Remote Sensing
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• v.39 no.2
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• pp.233-246
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• 2023

In terms of understanding the water cycle and efficient water resource management, the importance of soil moisture has been highlighted. However, in Korea, the lack of qualified in-situ soil moisture data results in very limited utility. Even if satellite-based data are applied, the absence of ground reference data makes objective evaluation and correction difficult. The cosmic-ray neutron probe (CRNP) can play a key role in producing data for satellite data calibration. The installation of CRNP is non-invasive, minimizing damage to the soil and vegetation environment, and has the advantage of having a spatial representative for the intermediate scale. These characteristics are advantageous to establish an observation network in Korea which has lots of mountainous areas with dense vegetation. Therefore, this study was conducted to evaluate the applicability of the CRNP soil moisture observatory in Korea as part of the establishment of a Korean cOsmic-ray Soil Moisture Observing System (KOSMOS). The CRNP observation station was installed with the Gunup-ri observation station, considering the ease of securing power and installation sites and the efficient use of other hydro-meteorological factors. In order to evaluate the CRNP soil moisture data, 12 additional in-situ soil moisture sensors were installed, and spatial representativeness was evaluated through a temporal stability analysis. The neutrons generated by CRNP were found to be about 1,087 counts per hour on average, which was lower than that of the Solmacheon observation station, indicating that the Hongcheon observation station has a more humid environment. Soil moisture was estimated through neutron correction and early-stage calibration of the observed neutron data. The CRNP soil moisture data showed a high correlation with r=0.82 and high accuracy with root mean square error=0.02 m³/m³ in validation with in-situ data, even in a short calibration period. It is expected that higher quality soil moisture data production with greater accuracy will be possible after recalibration with the accumulation of annual data reflecting seasonal patterns. These results, together with previous studies that verified the excellence of CRNP soil moisture data, suggest that high-quality soil moisture data can be produced when constructing KOSMOS.

• Nuclear Engineering and Technology
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• v.4 no.2
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• pp.83-89
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• 1972

The contents of the individual lanthanide elements are determined by neutron activation using a new comparator technique, which employs the short-lived radio-isotope of 56Mn as a neutron flux monitor. The total rare earths are separated as a group from the monazite sample before irradiation. After irradiation the rare earths are separated from each other by gradient elution with ammonium alpha-hydroxyisobutyrate using a cation-exchange column. The contents of 14 individual rare earths, from lutetium to lanthanum, are deter-mined.