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Development of a Dual-pulse RF Driver for an S-band (= 2856 MHz) RF Electron Linear Accelerator
Sungsu Cha,김유종,Byeong-No Lee,Byung Cheol Lee,Hyungki Cha,Jang Ho Ha,박형달,Seung Hyun Lee,Hui Su Kim,Pikad Buaphad 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.8
The radiation equipment research division of Korea Atomic Energy Research Institute has developed a Container Inspection System (CIS) using a Radio Frequency (RF) electron linear accelerator for port security. The primary purpose of the CIS is to detect nuclear materials and explosives, as well country-specific prohibited substances, e.g., smuggled. The CIS consists of a 9/6 MeV dualenergy electron linear accelerator for distinguishing between organic and inorganic materials. The accelerator consists of an electron gun, an RF accelerating structure, an RF driver, a modulator, electromagnets, a cooling system, a X-ray generating target, X-ray collimator, a detector, and a container moving system. The RF driver is an important part of the configuration because it is the RF power source: it supplies the RF power to the accelerating structure. A unique aspect of the RF driver is that it generates dual RF power to generate dual energy (9/6 MeV). The advantage of this RF driver is that it can allow the pulse width to vary and can be used to obtain a wide range of energy output, and pulse repetition rates up to 300 Hz. For this reason, 140 W (5 MW − 9 MeV) and 37 W (3.4 MW − 6 MeV) power outputs are available independently. A high power test for 20 minutes demonstrate that stable dual output powers can be generated. Moreover, the dual power can be applied to the accelerator which has stable accelerator operation. In this paper, the design, fabrication and high power test of the RF driver for the RF electron linear accelerator (linac) are presented.
Sungsu Cha,Yujong Kim,Jinsik Ju,Youngwoo Joo,Byeong-No Lee,Soo Min Lee,Jae Hyun Kim,Pikad Buaphad,Byung Cheol Lee,Hyungki Cha,Jang Ho Ha,Hyung Dal Park,Ki Beak Song,Seung Hyun Lee,Heesoo Kim 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.6
The Korea Atomic Energy Research Institute (KAERI) has been developing a Container Inspection System (CIS) by using a dual-energy (9/6 MeV) S-band (= 2856 MHz) electron linear accelerator. The key components of the CIS are the electron linear accelerator (including an electron gun, an accelerating structure, an RF power source, cooling chillers, vacuum pumps, magnet power supplies, and two solenoid magnets with beam focusing and shielding functions), a tungsten target for X-ray generation, an X-ray collimator, a detector array, and a container moving system. Generally, in accelerators, beam focusing is mainly done by solenoids operating in the region of a few MeV to keep the shape of transverse beam symmetrically round so as to reduce the loss of electrons, which increases the beam current and the beam power. In addition, a specially-designed component is needed to protect against the radiation due to the lost electrons. In this paper, we describe the design, fabrication, and optimization of two specially- designed solenoids with focusing and radiation shielding functions for a dual-energy S-band electron linear accelerator for a CIS.
형상 유사도 기반 피팅 검색을 위한 AutoCAD Plant 3D 플러그인 타입 시스템 개발
여창모(Changmo Yeo),김형기(Hyungki Kim),박찬석(Chanseok Park),김병철(Byung Chul Kim),문두환(Duhwan Mun),한순흥(Soonhung Han) (사)한국CDE학회 2018 한국CDE학회 논문집 Vol.23 No.2
Aged process plants have typically different configurations from those in the as-built status and thus 3D CAD models for the aged process plant have often been outdated due to the difficulty of data update activities. This situation disturbs the efficient and safe operation and maintenance of aged process plants. As a solution to this problem, 3D CAD models in the as-operated status are reversely generated from point cloud obtained using a laser scanning device. 3D modeling with a point cloud in a plant 3D CAD system needs retrieving catalogs for equipment and materials and placing them in 3D dimensional design space. To accomplish this, this study designs an AutoCAD Plant 3D-based plug-in type system for the shape similarity-based fitting retrieval and implements it according the design.
Kyuseok Song,Euo Chang Jung,Hyungki Cha,Jeongsik Moon,Sang Chun Lee 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.I
The characteristic behaviors of the post-ionized signals of neutral atoms generated by either ion beam sputtering or laser ablation were investigated by adopting a Pb plate as a target sample. The signal intensities and the threshold laser power for ion generation were compared for various the ion generation schemes, such as laser ablation with 532 nm laser only (Case I), 2-color resonant laser ablation by using 532 nm and 283.3 nm lasers (Case II), laser ablation with 532 nm laser followed by resonant post-ionization with 283.3 nm laser (case III), and 2-color resonant laser ablation followed by resonant post-ionization (case IV). Case I required the highest threshold laser power required for ion generation while Case III with a 500 ns delay between the two laser pulses, 532nm and 283.3 nm, required the least laser power for the generation of ion signals. A comparison of the ion signal intensities between case II and case IV revealed a variation in the signal intensity that depended on the time delay between the ablation laser pulse and the ionization laser pulse. Meanwhile, the post-ionization of the neutrals generated by ion beam sputtering (case V) showed a comparable ion signal to that of the post-ionization signal of the laser-induced plasma. The resonant post-ionization of the sputtered neutrals showed a more than 10 times signal enhancement with the use of a 100 times less laser power, 0.6 mW, when compared to the case of non-resonant laser ionization with 60 mW at 355 nm. The behavior of the ion signal of the sputtered neutrals was also investigated by varying the experimental parameters, such as the time delay between the ion beam pulse and the laser pulse, the ion beam pulse and the high voltage pulse for ion extraction, and the high voltage applied to the ion extraction.
송규석,Cha Hyungki,최인희,Jung Euo Chang,유희수 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.1
The isotopic composition of trace Yb and Pd in solution phase were determined by adopting laser ablation time-of-flight mass spectrometry and adsorbing samples onto metal plates, such as stainless steel, copper, and molybdenum. Ion signals from the Yb isotopes were observed easily with a reasonable mass resolution for standard solutions of 1 ppb to 1000 ppb. The minimum detectible concentration of Yb using this technique was estimated to be less than 1 ppb. Laser ablation mass spectrometry of the PdCl2 adsorbed onto a copper plate revealed various copper clusters with chloride ions such as, Cu2Cl, Cu3Cl2, Cu4Cl3, Cu2, Cu3, etc. The observation of palladium ion peaks in the laser ablation mass spectra was found to depend on the reaction time between the copper plate and the PdCl2 solution. These clusters were identified as being generated during the laser ablation process, not during the chemical reactions in the solution phase.la