• Title, Summary, Keyword: linac

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Design and Operational Charcteristics of 150MW Pulse Modulator (150MW 펄스 MODULATOR의 설계 및 동작특성)

  • Park, S.S.;Oh, J.S.;Lee, K.T.;Kim, S.H.;Son, Y.K.;Choi, K.;Chang, S.D.;Park, S.W.;Nam, S.H.;Cho, M.H.;NamKung, W.
    • Proceedings of the KIEE Conference
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    • pp.928-930
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    • 1992
  • The design beam energy of PLS(Pohang Accelerator Laboratory) Linac is 2Gev. The linac employs total 11 units of modulators and klystrons. The maximum peak output powers of the modulators are 200MW (400kV, 500A, 4.4$\mu$S flat-top, 800$\Omega$ load) to drive the klystrons which have the peak microwave power of 80MW. Prior to the development of the 200MW modulators, a prototype 150MW modulator has been constructed and tested. We have achieved output pulses of 350kV, 420A and 3.5$\mu$S flat-top with 840$\Omega$ water load. In this article, the test results and computer simulations of charging, De-Q'ing, and discharging are presented.

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Conceptual Design of the Superconducting Linac for KOMAC

  • Kim, Sang-Ho;Kim, Young-Hwan;Kim, Han-Sung;Lee, Kang ok;Chung, Kie-Hyung
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.967-971
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    • 1998
  • KOMAC (KOrea Multi-purpose Accelerator Complex) is the 1 Gev, 20 ㎃ proton linac. The superconducting linac for the high energy part acceleration from 100 MeV to 1 GeV is selected as a main candidate. As is well known, the superconducting linac has advantages for high current, high energy acceleration such as a large bore size, short accelerator length, and the RF efficiency. In this energy, the velocity of proton increases from $\beta$=0.87. For the design and fabrication simplicity, the cavity $\beta$ stages are divided into 3 parts. The maximum electric field in the cavity is designed below 20 ㎹/m. In this paper the design concepts and guides for this superconducting linac are introduced.

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Empirical Study on Medical LINAC System for Radiation Therapy (방사선 치료를 위한 의료용 선형 전자가속기에 대한 실증연구)

  • Park, Su-Mi;Song, Seung-Ho;Jo, Hyun-Bin;Jeong, Woo-Cheol;Jang, Sung-Roc;Ryoo, Hong-Je
    • Proceedings of the KIPE Conference
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    • pp.242-244
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    • 2019
  • 본 논문은 방사선 치료에 사용되는 선형 전자가속기(LINAC)의 작동 원리와 구성 등 의료용 LINAC의 전반을 다룬다. 의료용 LINAC은 전자총에서 발사된 전자를 가속기 튜브 내에서 가속시켜 전자빔을 발생시키고, 이러한 전자빔을 금속 표적에 충돌시켜 발생한 X 선을 인체에 조사하는 원리이다. 최근에는 O-arm, C-arm 등 3-D 촬영을 위한 치료기가 개발됨에 따라, 의료용 LINAC의 전자총, 마그네트론 등을 구동하는데 사용되는 고전압 전원장치 또한 소형화와 고밀도화가 요구되는 추세이다. 본 논문에서는 마그네트론 구동을 위한 고밀도 40kV/100A 음극성 펄스 모듈레이터와 정전압 정전류 제어 및 50kV 절연이 가능한 히터 전원장치를 설계 및 제작하였으며, 9.3GHz, 1.7MW X-Band 마그네트론 연계실험을 통해 고효율 고신뢰성의 동작을 확인하였다.

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Development and Performance Test of a New High Power RF Window in S-Band PLS-II LINAC

  • Hwang, Woon-Ha;Joo, Young-Do;Kim, Seung-Hwan;Choi, Jae-Young;Noh, Sung-Ju;Ryu, Ji-Wan;Cho, Young-Ki
    • Journal of the Korean Physical Society
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    • v.71 no.11
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    • pp.802-806
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    • 2017
  • A prototype of RF window was developed in collaboration with the Pohang Accelerator Laboratory (PAL) and domestic companies. High power performance tests of the single RF window were conducted at PAL to verify the operational characteristics for its application in the Pohang Light Source-II (PLS-II) linear accelerator (Linac). The tests were performed in the in-situ facility consisting of a modulator, klystron, waveguide network, vacuum system, cooling system, and RF analyzing equipment. The test results with Stanford linear accelerator energy doubler (SLED) have shown no breakdown up to 75 MW peak power with $4.5{\mu}s$ RF pulse width at a repetition rate of 10 Hz. The test results with the current operation level of PLS-II Linac confirm that the RF window well satisfies the criteria for PLS-II Linac operation.

DESIGN AND FABRICATION OF THE BEAM POSITION MONITOR FOR THE PEFP LINAC

  • Kwon, Hyeok-Jung;Kim, Han-Sung;Seol, Kyung-Tae;Ryu, Jin-Yeong;Jang, Ji-Ho;Cho, Yong-Sub
    • Nuclear Engineering and Technology
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    • v.45 no.4
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    • pp.523-528
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    • 2013
  • The beam position monitor (BPM) is an essential component for the PEFP 100-MeV linac's commissioning. A prototype stripline-type linac BPM was designedfor this purpose. The electrode aperture is 20 mm in diameter, and the electrode is 25 mm long, so it can be installed between Drift Tube Linac (DTL)101 and DTL102, which is the shortest distance. One end of the electrode is connected to the Sub Miniature Type A (SMA) feed through for signal measurement, and the other end is terminated as a short. The signal amplitude of the fundamental component was calculated and compared with that of the second harmonic component. The designed BPM was fabricated and a low-power RF test was conducted. In this paper, the design, fabrication and low power test of the BPM for the PEFP linac are presented.

SRF LINAC FOR FUTURE EXTENSION OF THE PEFP

  • Kim, Han-Sung;Kwon, Hyeok-Jung;Seol, Kyung-Tae;Jang, Ji-Ho;Cho, Yong-Sub
    • Nuclear Engineering and Technology
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    • v.46 no.2
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    • pp.247-254
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    • 2014
  • A study on the superconducting RF linac is underway in order to increase the beam energy up to 1 GeV by extending the Proton Engineering Frontier Project (PEFP) 100-MeV linac. The operating frequency of the PEFP superconducting linac (SCL) is 700 MHz, which is determined by the fact that the frequency of the existing normal conducting linac is 350 MHz. A preliminary study on the beam dynamics showed that two types of cavities with geometrical betas of 0.50 and 0.74 could cover the entire energy range from 100 MeV to 1 GeV. An inductive output tube (IOT) based RF system is under consideration as a high-power RF source for the SCL due to its low operating voltage and high efficiency. As a prototyping activity for a reduced beta cavity, a five-cell cavity with a geometrical beta of 0.42 was designed and fabricated. A vertical test of the prototype cavity at low temperatures was performed to check the performance of the cavity. The design study and the prototyping activity for the PEFP SCL will be presented in this paper.

Modeling of Dual Head Gantry Radiotherapy System with Monte Carlo Simulation (듀얼 헤드 갠트리 방사선치료 시스템 설계를 위한 몬테칼로 시뮬레이션 연구)

  • Park, Seungwoo
    • Journal of radiological science and technology
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    • v.40 no.4
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    • pp.627-632
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    • 2017
  • In order to design a dual-head gantry radiotherapy system, the single head of LINAC was modeled using GATE as a preliminary study. The LINAC head was designed with VARIAN manufacturer's information. 6 MV photons were generated from the head and the photons w irradiated to a water phantom for beam evaluation. GATE simulation was segmented by two stages, the one was to generate X-ray spectrum and the other one was for irradiation X-ray to the water phantom. The quantitative results were described in Percentage depth dose and beam profile. Two field size conditions were employed as $5{\times}5$ and $10{\times}10cm^2$. After beam quality was verified, dual heads gantry radiotherapy system were simulated and they was compared to the single head of LINAC system in terms of dose deposition with in the phantom. The simulated LINAC head showed acceptable beam quality result for radiotherapy. The efficiency was calculated that deposited dose from dual heads was divided by the dose from single head. At all conditions, dual heads showed higher treatment efficiency. Efficiency was increased about 40 to 60%. Form the result, The dual head gantry system of new LINAC system will contribute to the practical radiotherapy of tumor and to reduce treatment time.

Variation of Indoor Average Ozone Concentration within the Radiation Therapy Room by High Energy Radiation (고 에너지 방사선에 기인된 방사선치료실 내 평균 오존 농도의 변화)

  • Lee, Jin-kook;Lee, Hyo-Yeong;Im, In-Chul;Yu, Yun-Sik
    • Journal of the Korean Society of Radiology
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    • v.10 no.3
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    • pp.171-180
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    • 2016
  • This study was to evaluate the change in characteristics of concentration of ozone after exposure to high energy radiation in linac room. Background ozone concentration of linac room was measured and compared to ozone concentration around linac room. Background ozone concentration of linac room was mean $17.4{\pm}7.9ppb$. It was 50% of the ozone concentration($36.8{\pm}22.3ppb$) around linac room(p<0.05). The concentration of ozone after exposure to high energy radiation in linac room was elevated to double of background ozone level, intensity after exposure. with exposure time concentration of ozone increased proportionally. It showed maximum level at 130~180seconds and slowed a tendency to saturate. It required more than 10 minutes for ozone concentration in linac room to drop to ozone concentration around linac room. The concentration of ozone after exposure to high energy radiation is high enough to cause specific physical symptoms, such as acute dyspnea or chest pain due to dry cough. Exposure to high concentration of ozone in sealed linac room can aggravate pulmonary disease, so special attention is needed.