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Development of a monoenergetic neutron field utilizing an accelerator deuteron beam
Park Hyeoungwoo,Kang Sinchul,Kim Jungho,Park Hyeonseo,Kim Joong Hyun,Yoon Young Soo 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.83 No.8
A monoenergetic neutron feld is an attractive environment for neutron metrology and the development of novel neutron detectors. Deuterium–deuterium and deuterium–tritium (DT) reactions with an accelerated deuteron beam produce 2.5 and 14.8 MeV monoenergetic neutrons, respectively. The Korea Research Institute of Standards and Science (KRISS) is developing a monoenergetic neutron feld facility with an accelerator that generates a deuteron beam to establish monoenergetic neutron measurement standards. An electrostatic accelerator with a maximum high voltage of 400 kV and beam current from 0.5 to 500 μA from High Voltage Engineering Europa BV was installed. For a tritiated titanium or deuterated titanium target deposited at 250 μg/cm2 on a 38 mm copper plate, a target chamber is developed by KRISS. The total neutron yield is limited to 5× 108 n/s, which is the maximum allowed emission rate resulting from the shielding capacitance of a laboratory wall shield. The corresponding deuteron beam current of the DT reaction with the maximum emission rate is approximately 15 μA. Furthermore, various additional studies such as beam current monitoring, target temperature monitoring, air cooling for the target, and beam profle measurement have been performed for the stable generation of the monoenergetic neutron feld.
Long counter and its application for the calibration of the neutron irradiators
Park, Hyeonseo,Kim, Jungho,Choi, Kil-Oung Nuclear Technology Publishing 2014 Radiation Protection Dosimeetry Vol.161 No.1
<P>The Korea Research Institute of Standards and Science (KRISS) has constructed a new long counter that can be disassembled in parts and reassembled. This counter can be easily transported and used as a transfer standard instrument for neutron fluence measurements. The response function and the effective centre of the counter are investigated by calculating neutron energies from thermal to 30 MeV using MCNPX. By carrying out measurements using a <SUP>252</SUP>Cf source in the KRISS irradiation room, the accuracy of the evaluated effective centre position is confirmed. The ‘distance variation method’ is adopted to eliminate the effect of inscatter neutrons. This method is effective and used for the experimental determination of the effective centre. The neutron emission rates determined by the neutron fluence measurements using the long counter developed are compared with those measured by a manganese sulphate bath, and show good agreement within 3 %.</P>
The absolute measurment of the neutron emission rate with Manganese Sulphate Bath system
Hyeonseo Park,Jong-Man Lee,Kil-Oung Choi,Kyung-Beom Lee,Miloslav Kralik,Myung Sup Hahn 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.47 No.4
Recently, an absolute measurements of the neutron emission rates of neutron sources were carried out for 241Am . Be and 252Cf over a wide range of emission rates (2 × 105 2 × 108 s.1). The measurements were done using a Manganese Sulphate Bath method, which is the principal method for the absolute determination of the neutron emission rates of radionuclide neutron sources. The efficiency of the system was determined by means of a 56Mn radioactive source of well-defined activity. Various corrections, including epithermal neutron capture, the (n, p) and the (n, ) reactions, the leakage of neutrons, etc., were replaced by a direct calculation of the neutron capture probability for manganese nuclei. The neutron capture probability of the manganese nuclei was determined by using a careful MCNP (Monte Carlo N-Particle Transport Code System) calculation and was 0.102 0.105 for the present status of the KRISS (Korea Research Institute of Standards and Science) Manganese Sulphate Bath system. The emission rates were determined with an uncertainty of < 0.8 % (k = 1)
합성 데이터셋을 이용한 산업용 계량기 문자 Detection 의 성능 향상
박찬우(Chanwoo Park),조현서(Hyeonseo Cho),남현길(Hyeongil Nam),박종일(Jong-Il Park) 한국방송·미디어공학회 2023 한국방송공학회 학술발표대회 논문집 Vol.2023 No.11
산업용 아날로그 계량기 내의 문자는 계기 숫자판이 돌아가는 등의 특수한 상황들이 다수 존재한다. 그러나 여전히 기존의 데이터셋으로 산업용 아날로그 계량기 문자의 탐지에 한계를 보인다. 본 논문에서는 산업용 아날로그 계량기 문자 탐지의 성능 향상을 위해, 3 차원 아날로그 계량기 모델을 활용하여 실제 환경과 유사한 합성 데이터셋 생성 방법을 제안한다. 구체적으로 3 차원 아날로그 계량기 모델의 조작을 비롯한, 카메라의 위치 방향, 주변 조명, 그림자 등의 실제와 유사한 3 차원 상의 효과들을 반영하여 합성 데이터셋을 구축한다. 또한 합성 데이터셋과 기존 데이터셋으로 학습된 각 모델의 문자 탐지 결과 비교를 통해서, 성능이 향상되었음을 확인한다.
Factors affecting forced eruption duration of impacted and labially displaced canines
Shin, Hyeonseo,Park, Mira,Chae, Jong-Moon,Lee, Jun,Lim, Hun Jun,Kim, Bong Chul Elsevier 2019 American journal of orthodontics and dentofacial o Vol.156 No.6
<P><B>Introduction</B></P> <P>Patients with impacted maxillary canines typically endure long treatment time, and reliable pretreatment estimates of orthodontic treatment duration would be beneficial to patients and clinicians. The purpose of this study was to identify factors that affect the duration of forced eruption for impacted maxillary canines.</P> <P><B>Methods</B></P> <P>Data from treatment records and radiographic scans of 27 patients with 29 impacted and labially displaced maxillary canines (25 unilateral, 2 bilateral) were collected. The patients underwent surgical and orthodontic interventions to bring the canine into the dental arch. Linear and angular measurements between the cusp tip and various reference planes were made on 3-dimensional images. Measurements associated with dental follicle, bone density, and canine root length were also obtained. Data were analyzed using simple linear regression and stepwise regression analysis.</P> <P><B>Results</B></P> <P>A total of 29 treated canines moved into the arch over a period of 13.0 ± 8.3 months (range, 5-33 months). Simple regression analysis showed that the only significant factor, with duration of traction as the dependent factor, was pretreatment inclination of the canines toward the midsagittal plane; stepwise regression analysis indicated a strong direct correlation between the duration of traction and this factor. The other variables were not significantly associated with the duration of traction.</P> <P><B>Conclusions</B></P> <P>The inclination of canines toward the midsagittal plane was found to be a reliable predictor of the duration of forced eruption for impacted maxillary canines.</P> <P><B>Highlights</B></P> <P> <UL> <LI> All canines moved into the arch during the time of 13.0 ± 8.3 months. </LI> <LI> Only significant factor was inclination of canines toward the midsagittal plane. </LI> <LI> The other variables are not associated significantly with the duration. </LI> </UL> </P>