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In-Core Power Measurement Using SiC Semiconductor Detector
Junesic Park,Jae Bum Son,Yong Kyun Kim,Se Hwan Park 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.4
A SiC detector was fabricated and tested in harsh radiation environment of the High Flux Advanced Neutron Application Reactor (HANARO) reactor core at Korea Atomic Energy Research Institute (KAERI). A 4H-SiC with 30 μm thick epitaxial layer was used as the radiation sensor, and the detector was designed to be tolerable against thermal and radiation damages. Alpha response and I-V characteristics of fabricated SiC sensor was measured and detection performance of the SiC detector was evaluated in a neutron field of HANARO ex-core neutron irradiation facility. After preliminary tests, reactor power monitoring using the SiC detector was carried out by inserting it into the HANARO irradiation hole, IP-4. Radiation-induced current of the detector was recorded as reactor power increased up to 10 MWth. Maximum thermal and fast neutron fluxes were 9.4×10^12 and 2.5×10^9 neutrons/cm^2/sec, respectively, and total neutron fluence irradiated on the detector was 4.7×10^16 neutrons/cm^2. The detector showed good linearity of response up to the tested fluence, with R^2 = 0.9997. Response speed of SiC detector was compared to that of a Rh self-powered neutron detector (SPND) in terms of signal saturation time. Averaged SiC detector saturation time was 12.8 seconds, approximately 11 times faster that of the Rh SPND.
Design study for the KOBRA (KOrea Broad acceptance Recoil spectrometer and Apparatus) at RAON
Park, Junesic,Kwon, Young Kwan,Moon, Jun Young,Komatsubara, Tetsuro,Jung, In-Il,Kim, Yong Hak,Yun, Chong Cheoul,Kim, Yong-Kyun,Kato, Seigo,Moon, Chang-Bum,Chae, Kyung Yuk,Kubono, Shigeru 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. No.
Design optimization of real-time in-containment 16N beta detection system
Park Junesic,Kim Yong Hyun,Pak Kihong,Kim Jae Chang,Jeong Jae Young,Cho Young-Sik,Kim Yong Kyun,Son Jaebum 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.82 No.3
The design process for optimizing a real-time 16N beta monitoring system inside a containment building was developed in this study. The purpose of the system is to detect the unidentifed small leaks (less than 0.5 gpm/h) of the primary and secondary coolant system of a pressurized water reactor, based on radiation measurements. The system is located at the annulus zone of the reactor containment building, away from the high radiation background, and detects the 16N beta particles that are transported to the system after collection at the leakage points of the reactor coolant system. The specifcations of the overall system were determined using Monte Carlo and computational fuid dynamics simulations. In particular, the optimization process for the shielding and collection cavity geometry has been described. A 5 cm lead shielding was determined considering the efcient weight reduction of the system and the radiation tolerance of the detector system over the reactor life. Assuming a 16N concentration of 1000 Bq/cc in the designed air collection cavity (2000 cc volume), the signal-to-noise ratio was evaluated to be approximately 2.2, and the leakage could be confrmed in the background radiation environment in the annulus zone. Based on the derived specifcations, a system prototype was manufactured considering structural safety.
Beam line design and beam transport calculation for the μSR facility at RAON
Pak, Kihong,Park, Junesic,Jeong, Jae Young,Kim, Jae Chang,Kim, Kyungmin,Kim, Yong Hyun,Son, Jaebum,Lee, Ju Hahn,Lee, Wonjun,Kim, Yong Kyun Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.10
The Rare Isotope Science Project was launched in 2011 in Korea toward constructing the Rare isotope Accelerator complex for ON line experiments (RAON). RAON will house several experimental systems, including the Muon Spin Rotation/Relaxation/Resonance (μSR) facility in High Energy Experimental Building B. This facility will use 600-MeV protons with a maximum current of 660 pμA and beam power of 400 kW. The key μSR features will facilitate projects related to condensed-matter and nuclear physics. Typical experiments require a few million surface muons fully spin-polarized opposite to their momentum for application to small samples. Here, we describe the design of a muon transport beam line for delivering the requisite muon numbers and the electromagnetic-component specifications in the μSR facility. We determine the beam-line configuration via beam-optics calculations and the transmission efficiency via single-particle tracking simulations. The electromagnet properties, including fringe field effects, are applied for each component in the calculations. The designed surface-muon beamline is 17.3 m long, consisting of 2 solenoids, 2 dipoles affording 70° deflection, 9 quadrupoles, and a Wien filter to eliminate contaminant positrons. The average incident-muon flux and spin rotation angle are estimated as 5.2 × 10<sup>6</sup> μ<sup>+</sup>/s and 45°, respectively.
Beam Optics Design for the μSR Facility at the RAON Facility in Korea
Pak Kihong,Park Junesic,Kim Yong Hyun,Lee Hyeonjun,Kim Yong Kyun,Lee Ju Hahn 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.5
The beam optics was evaluated to determine the specifications for the electromagnets in the proton beamline and the surface muon beamline at the RAON facility. Beam optics was evaluated, up to the fifth order by using GICOSY software; fringe field effects were also investigated. The distributions of the position and the angular divergence of 600-MeV protons were assumed to be Gaussian, and the initial beam emittance was 0.125 π mm mrad. The proton beamline was optimized by adjusting the positions and the magnetic fields of the electromagnetic components. The full width at half maximum (FWHM) proton beam size at the muon production target was 2.75 mm (x) × 6.73 mm (y), which met the requirement for achieving the maximum surface-muon production at the target. The designed surface-muon beamline is 23-m long and consists of two solenoids, two dipoles with a deflection angle of 70°, six quadrupoles, and a Wien filter. For an initial muon beam size of 6 cm (x) × 2 cm (y), the expected muon intensity at the end of the beamline, where the muon irradiation sample will be located, was estimated to be 7.7 × 107 per second.
Performance of 3D printed plastic scintillators for gamma-ray detection
Kim, Dong-geon,Lee, Sangmin,Park, Junesic,Son, Jaebum,Kim, Tae Hoon,Kim, Yong Hyun,Pak, Kihong,Kim, Yong Kyun Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.12
Digital light processing three-dimensional (3D) printing technique is a powerful tool to rapidly manufacture plastic scintillators of almost any shape or geometric features. In our previous study, the main properties of light output and transmission were analyzed. However, a more detailed study of the other properties is required to develop 3D printed plastic scintillators with expectable and reproducible properties. The 3D printed plastic scintillator displayed an average decay time constants of 15.6 ns, intrinsic energy resolution of 13.2%, and intrinsic detection efficiency of 6.81% for 477 keV Compton electrons from the <sup>137</sup>Cs γ-ray source. The 3D printed plastic scintillator showed a similar decay time and intrinsic detection efficiency as that of a commercial plastic scintillator BC408. Furthermore, the presented estimates for the properties showed good agreement with the analyzed data.
Improved 3D Printing Plastic Scintillator Fabrication
Jae Bum Son,Dong Geon Kim,Sangmin Lee,Junesic Park,Yong-Hyun Kim,Schaarschmidt Thomas,Yong Kyun Kim 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.7
3D printing techniques can be widely used for various applications owing to their fast speed, convenience, and customized shape output. The 3D printing technique is applicable to plastic scintillator fabrication which typically uses polymerization. Currently, research on application of the 3D printing technique based on photopolymerization to plastic scintillator fabrication is being pursued. However, performance of the photopolymerized scintillators reported till now is lower than that of commercial plastic scintillators ( 30%). We have carried out research on performance improvement of the scintillator fabricated by the photopolymerization, for radiation dose measure- ment. Photopolymer resin with novel recipe based on acrylic monomer and naphthalene was used to fabricate the scintillator instead of the photopolymer resin based on styrene, which is typically used as the monomer for commercial scintillator. 3D printer with digital light processing was used for the photopolymerization of the photopolymer resin. As a result, light output performance of the fabricated plastic scintillator was about 67% compared with that of the commercial plastic scintillator, BC-408. The performance of the scintillator fabricated by the photopolymerization was thus improved to more than two times that obtained by previous researchers. This is sucient to be applied to the radiation dose measurement with high dose rates such as radiation therapy. It also demonstrated the applicability of the 3D printing technique in scintillator fabrication.
Design of muon production target system for the RAON μSR facility in Korea
Jeong, Jae Young,Kim, Jae Chang,Kim, Yonghyun,Pak, Kihong,Kim, Kyungmin,Park, Junesic,Son, Jaebum,Kim, Yong Kyun,Lee, Wonjun,Lee, Ju Hahn Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.9
Following the launch of Rare Isotope Science Project in December 2011, a heavy ion accelerator complex in South Korea, named RAON, has since been designed. It includes a muon facility for muon spin rotation, relaxation, and resonance. The facility will be provided with 600 MeV and 100 kW (one-fourth of the maximum power) proton beam. In this study, the graphite target in RAON was designed to have a rotating disk shape and was cooled by radiative heat transfer. This cool-down process has the following advantages: a low-temperature gradient in the target and the absence of a liquid coolant cooling system. Monte Carlo simulations and ANSYS calculations were performed to optimize the target system in a thermally stable condition when the 100 kW proton beam collided with the target. A comparison between the simulation and experimental data was also included in the design process to obtain reliable results. The final design of the target system will be completed within 2020, and its manufacturing is in progress. The manufactured target system will be installed at the RAON in the Sindong area near Daejeon-city in 2021 to carry out verification experiments.