• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2064-2069
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• 2008

The Resonance Control Cooling System (RCCS) prototype installed in KAERI site has been designed to control the resonant frequency of the normal conducting drift tube linac (DTL) for the Proton Engineering Frontier Project (PEFP). The RCCS water pumping skid is composed of two channels as a by-passing the cooling water and a plate heat exchanger. The required temperature can be achieved by mixing both channels in order to control its the resonant frequency at 350 MHz. The temperature controlled water pumping skid operates in combination with the Low Level Radio Frequency (LLRF) system. We have discussed the design, modeling with each components, control scheme, fabrication and test results of the water pumping skid for resonant frequency control of the DTL cavity. In conclusion, the fabricated RCCS prototype through the optimization of modeling has corresponded with the design requirement and concept.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.540-544
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• 2017

In this study, we analyzed the effects of TID(Total Ionizing Dese) and TREE(Transient Radiation Effects on Electronics) on nMOSFET and pMOSFET fabricated by 0.18um CMOS process. The size of nMOSFET and pMOSFET is 100um/1um(W/L). The TID test was conducted up to 1 Mrad(Si) with a gamma-ray(Co-60). During the TID test, the nMOSFET generated leakage current proportional to the applied dose, but that of the pMOSFET was remained in a steady state. The TREE test was conducted at TEST LINAC in Pohang Accelerator Laboratory with a maximum dose-rate of $3.16{\times}10^8rad(si)/s$. In that test nMOESFET generated a large amount of photocurrent at a maximum of $3.16{\times}10^8rad(si)/s$. Whereas, pMOSFETs showed high TREE immunity with a little amount of photocurrent at the same dose rate. Based on the results of this experiment, we will progress the research of the radiation hardening for CMOS unit devices.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.547-550
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• 2011

We measured that is Gantry, Collimator Star Shot, Light vs. Radiation, HDR QA with Medical LINAC Then, PACS was implemented on the digital images on the monitor that can be confirmed through the QA. Also, for cooperation with OCS system that is using from present source and impose code that need in treatment in each treatment, did so that Order that connect to network, input to CR may appear, did so that can solve support data mistake of Pinacle and PACS that is Planning System and look at Planning premier in PACS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.380-383
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• 2003

The purpose of this study is to develope prototype EPID system and improve image quality of radiation therapy field imaging system using CCD camera. For this research we used Linac(Clinac 4/100), Copper metal plate, $Gd_2O_2S_2$ phosphor and CCD camera(Photronic). In this study we find best thickness of buil-up metal plate and acquired projection image of humanoid head phantom. Also we enhanced raw image data using superposition and histogram stretching method. Through the thickness optimized of metal plate and image processing, we confirmed of an improved image quality of an EPID system using CCD camera. As result, highest quality image was acquired at 1mm thickness of Copper metal plate and improved image quality by image processing methods.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1530-1533
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• 2005

Total 12 units of high power klystron-modulator systems as microwave source is under operation for 2.5-GeV electron linear accelerator in Pohang Light Source(PLS) linac. RF power and beam power of klystron are precisely measured for the effective control of electron beam. A precise measurement and measurement equipment with good response characteristics are required for this. Input power of klystron is calculated from the applied voltage and the current on its cathode. Tiny measurement error severely effects RF output power value of klystron. Therefore, special care is needed to measure precise beam voltage. Capacitive voltage divider(CVD) unit is intended for the measurement of beam voltage of 400 kV generated from the pulsed klystron-modulator system. Main parameter to determine the standard capacitance in the high arm of CVD is dielectric constant of insulation oil. Therefore CVD should be designed to have a minimum capacitance variation due to voltage, frequency and temperature in the measurement range. This paper will discuss the analysis of capacitive voltage divider for a pulsed high-voltage measurement, and the empirical relations between capacitance and oil temperature variation.

• Journal of the Korean Society of Radiology
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• v.1 no.3
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• pp.11-16
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• 2007

In this study, the potential of a newly developed simulation toolkit, GATE for the simulation of electronic portal imaging devices (EPID) in radiation therapy was evaluated by characterizing the performance of the metal plate/phosphor screen detector for EPID. We compared the performances of the GATE simulator against MCNP4B code and experimental data obtained with the EPID system in order to validate its use for radiation therapy.

• Nuclear Engineering and Technology
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• v.49 no.5
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• pp.1071-1078
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• 2017

A buncher is one of the main pieces of equipment in the medium energy beam transport line (MEBT) for China accelerator driven sub-critical system (C-ADS) Injector II. To focus the beam longitudinally and match the beam for the acceptance of the superconducting linac section, two room temperature quarter wave resonator (QWR) bunchers with frequency of 162.5 MHz have been designed as parts of the MEBT. According to the beam transmission matching of the MEBT and the geometric parameters requirements of bunchers, the unique mechanical structure and the main processing technology of buncher cavities and their couplers and tuners are described in this paper. The fabrication of bunchers and their parts have been completed and tested at high power, the test results agree well with the design requirements. These bunchers work well for about two years in Institute of Modern Physics, Chinese Academy of Sciences.

• Journal of the Korean Society of Radiology
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• v.13 no.1
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• pp.45-53
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• 2019

This study is a neutron activation for concrete that shields medical linear accelerator facilities. Comparison of general concrete and low activation concrete. The simulation method was simulated using MCNPX (Ver. 2.5.0) and FISPACT-2010, and the shielding ability for photon and neutron beams was calculated and neutron activation evaluation was carried out. As a result, the shielding capacity was 20 ~ 50 cm efficient in general concrete, and activate evaluation in low activation concrete was calculated to be low in radioactivity concrete, but all were estimated to not exceed their own allowable concentration in self - disposal. As a result of the comprehensive analysis, it is considered effective to use ordinary concrete.

• Journal of Radiation Industry
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• v.12 no.4
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• pp.297-302
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• 2018

The wedge filter has two movements, fixed and dynamic. In this study, the depth dose distribution was analyzed to determine the stability of the dose distribution and dose volume histograms obtained by evaluating the usability of the critical normal tissue dose around the tumor dose. The depth dose was analyzed from the dose distribution from a Linac (6 MV and 10 MV irradiation field of energy $20{\times}20cm^2$, wedge filter with a SSD of 100 cm and $15^{\circ}$, $30^{\circ}$, $45^{\circ}$ Y1-in (Left -7 cm), Y2-out(Right +7 cm). To analyze the fluctuations of the depth dose, a fixed wedge and dynamic wedge toe portion was examined according to the energy and angle because the size of the fluctuations was included in the error bound and did not show significant differences. The neck, breast, and pelvic dosimetry in tumor tissue are measured more commonly with a dynamic wedge than a fixed wedge presumably due to the error range. On the other hand, dosimetry of the surrounding normal tissue is more common using a fixed wedge than with a dynamic wedge.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.449-455
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• 2022

The rapid rise in the application of novel treatment techniques, such as intensity-modulated radiotherapy (IMRT), motivated us to survey the status of Korea's radiation safety management and the shielding designs of facilities employing medical linear accelerators (LINACs). To this end, a questionnaire was used to collect information on LINAC facilities and treatments, workload, shielding design, shielding management, and path of obtaining shielding information. Out of 100 domestic institutions, 52 responded to the survey. Approximately 70% of the institutions utilized IMRT for more than 60% of their cases, and an IMRT factor of 5 was adopted by 75% of these institutions. Over 80% of the institutions accounted for the applied time-averaged dose rate per week and instantaneous dose equivalent rates in their shielding designs. Approximately 45% of the institutions obtained important shielding information via a radiation shielding design company and the NCRP-151 report. Overall, most facilities were shown to follow the standards recommended by the relevant international agencies. However, the requirement to establish standardized shielding design information and clarify ambiguous paths for information acquisition was also highlighted. Therefore, the study's results can be used as a foundation for establishing a safety control system and for creating adequate shielding designs.