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Development of a Li-Coated RPC for Low-Energy Neutron Detection
이경세,심광숙,김병일,홍병식,김현철,김지현,이광복,Mikiko Ito,류민상,홍성종,안성환,박성근,강태임 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.4
In this report, we present a newly developed hybrid resistive plate chamber (RPC) for the detection of low-energy neutrons. Lithium-°uoride (LiF) enriched for the 6Li isotope was chosen as the material sensitive to low-energy neutrons for the construction of the hybrid RPC. The LiF-coated RPC was tested by using the 252Cf neutron-irradiation facility at the Korea Atomic Energy Research Institute (KAERI). The detection e±ciency of the double-layered LiF-coated RPC to neutrons in the energy range from 10 to 560 meV was approximately 1.6 %. We obtained reliable e±ciency plateaus over a wide range of electric-.eld intensities.
Development of Thin Gaseous Ionization Detectors for Measurements of High-energy Hadron Beams
이경세,홍병식,이기수,박성근,유재희,Sang Yeol Kim 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.7
Thin gaseous ionization detectors have been developed based on a current-integration mode formeasurements of high-energy hadron beams. In the present detector R&D, two different types ofprototype detectors with an active area of 16 × 16 cm2, each equipped with 256-signal processingchannels, were manufactured and tested with 43-MeV protons provided by the MC50 proton cyclotronat the Korea Institute of Radiological and Medical Science (KIRAMS). The first one wasequipped with a single gas electron multiplier (GEM), and the second one was a thin-plane ionizationdetector without the GEM foil loaded. The linearities of the detector responses for bothdetectors were examined for various proton-beam intensities. The quantitative accuracies for thechannel-response data and for the total detector responses measured for 43-MeV protons were 0.4%and 0.34%, respectively. We conclude from the beam test that operating both types of detectors inthe current-integration mode will allow quality measurements of dynamic-mode hadron beams tobe performed with accuracies of better than 1%.
Development of a LYSO-array Detector for Measurement of Proton-beam Pro¯les
이경세,B. S. Moon,B. Hong,J. Jang,M. S. Jeong,M. Jo,E. A. Ju,S. Park,K. S. Sim 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.4
Here, we report on the development of a beam-scan detector that can quantitatively measure proton-beam profiles. The core component of the beam-scan detector is composed of 46 0.9-mm-thick LYSO (lutetium yttrium oxyorthosilicate) scintillators. The LYSO-scintillator array was equipped with a 46-channel silicon photodiode and current-mode signal processing electronics. The beam-scan detector was tested with 45-MeV proton beams provided by the MC50 proton cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS). This system has been shown to reliably detect and measure proton-beam profiles at currents ranging from 1 to 5 nA. We expect the current beam detector operating in the charge-integration mode to allow us to perform qualify measurements for therapeutic proton and heavy-ion beams.
Scintillation-Fiber Detection for Dose Verification in Hadron Therapy
이경세,홍병식,Genie Jhang,주은아,김총,박성근,이한범,심현하,심광숙 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.4
In this paper, we report on the development of a scintillation-fiber detection method for dose verification in hadron therapy. In order to achieve the position sensitivity required for precision measurement of doses, a detector composed of 1-mm-thick scintillation fibers and a multi-channel photodiode was constructed and tested with 45-MeV proton beams provided by the MC50 proton cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS). The results of the beam test showed that the spatial resolution of the data determined by using the standard deviation σ was ∼1.0 mm, which is sufficiently accurate to verify beam-induced doses in hadron therapy. Furthermore, the quantitative accuracy appearing in the data is on the order of ∼1%. We expect the detector composed of scintillation fibers and operating in the charge-integration mode to allow us to perform quality measurement of doses in various hadron therapies.
Radiation Tests for a Single-GEM-Loaded Gaseous Detector
이경세,홍병식,박성근,Sang Yeol Kim 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.9
We report on a systematic study of a single-gas-electron-multiplier (GEM)-loaded gaseous detectordeveloped for precision measurements of high-energy particle beams and for dose verification inparticle therapy. In the present study, a 256-channel prototype detector having an active area of 16× 16 cm2 and operating using a continuous current-integration-mode signal-processing method wasmanufactured and tested with X-rays emitted from a 70-kV X-ray generator and 43-MeV protonsprovided by the MC50 proton cyclotron at the Korea Institute of Radiological and Medical Science(KIRAMS). The amplified detector response was measured for X-rays with an intensity of about5 × 106 Hz cm−2. The linearity of the detector response to the particle flux was examined andvalidated by using 43-MeV proton beams. The non-uniform development of the amplification forthe gas electrons in space was corrected by applying a proper calibration to the channel responses ofthe measured beam-profile data. We conclude from the radiation tests that the detector developedin the present study will allow us to perform quality measurements of various high-energy particlebeams and to apply the technology to dose-verification measurements in particle therapy.
Charge-Integration-Mode Detection for Measurements of Particle Beams
이경세,홍병식,G. Jhang,M. Jo,E. Ju,B. S. Moon,박성근,H. B. Rhee,H. H. Shim,심광숙 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
In this paper, we report on the beam-detection technique in a charge-integration mode. The novel radiation-detection method has been applied to detectors for quantitative measurements of proton and fast-neutron beams. First, we developed a beam detector equipped with a scintillation-fiber array and a 46-channel silicon photodiode to measure proton-beam induced fast neutrons. Second, the scintillator fibers in the detector were replaced by LYSO crystals to measure proton beams provided by a 50-MeV proton cyclotron. The detectors operating in the current detection technique were tested with fast-neutron and proton beams provided by the MC50 proton cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS). We conclude from the beam tests that the current detectors operating in the charge-integration mode are capable of qualified and reliable measurements both for proton and fast-neutron beams.
이경세(K.S. Lee),백제현(J.H. Baek) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.11
In this study, a vortex visualization method based on the vorticity magnitude is developed. One of the simplest models jar a vortex is a vortex filament with the maximum vorticity on its center. The proposed method is based on the observation of this ideal distribution of vorticity magnitude. Laplacian and Hessian matrix of vorticity magnitude are tested for detecting the local maximum of vorticity magnitude. These ideas were applied to wake flow past a sphere. It was found that the Laplacian method is not able to distinguish vortices from the underlying shear layer clearly, while the Hessian matrix method does not suffer from this problem.
이경세(Kyung Seh Lee),백제현(Je Hyun Baek) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-
A large eddy simulation with explicit filters on unstructured mesh is presented. The flow filed is semi-implicitly marched by a fractional step method. Spatial discretization of the solver is designed to guarantee the second order accuracy. Two explicit filters are adopted for reducing the aliasing error of the nonlinear convective term and measuring the level of subgrid scale velocity fluctuation, respectively. The filters are linearity-preserving and have second order commutation error. The developed subgrid scale model is basically eddy viscosity model which depends on the explicitly filtered fields and needs no additional ad hoc wall treatment, such as van Driest damping function. As a validation problem, the flows around a sphere at several Reynolds numbers, including laminar and turbulent regimes, are calculated and compared to experimental data and numerical results in the literature.