• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.111.2-111.2
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• 2013

고주파 전자가속기는 고출력 RF 시스템으로 구동된다. 이러한 고주파 전자가속기에서 고출력 RF 시스템은 종종 고출력 방전으로 인해 가속관에 손상을 입힐 수 있기 때문에 조심스럽게 RF conditioning을 진행 하여야 한다. 일반적으로 RF conditioning은 아주 긴 시간을 필요로 하고, RF 출력을 서서히 높여가며 진행할 필요성이 있다. 한국원자력연구원에서는 9 MeV와 6 MeV 에너지를 출력하기 위해서는 가속관으로 RF 입력을 약 5.5 MW까지 RF conditioning을 진행하여야 한다. 따라서, 본 연구에서는 Klystron 최대 출력이 약 5.5 MW로 한국원자력연구원에서 개발된 S-band (2,856 MHz) RF 전자가속관에 RF conditioning을 진행 하였다. 가속관의 진공을 약 1.0e-7을 유지하면서 반복률을 10 Hz부터 180 Hz로 증가시켰고, RF 입력 파워는 약 6 MW까지 RF conditioning을 진행 하였다. 그 결과 짧은 시간에 RF commissioning을 진행할 수 있었다.

• 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.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1365-1367
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• 1995

The PLS 2-GeV linac employs 11 units of high-power pulsed klystrons(80MW) as the main RF sources. The matching modulators of 200 MW(400kV, 500 A) can provide a flat-top pulse width of 4.4 ${\mu}s$ with a maximum pulse repetition rate of 120 Hz at the full power level. For a good stability of electron beams, the pulse-to-pulse flat-top voltage variation of a modulator requires less than 0.5%. In order to achieve this goal, we stabilized high voltage charging power supplies within 1% by a phase controlled SCR voltage regulator. In addition, we employed ac/dc feedback together with a resistive De-Q'ing system to achieve far less than 0.5% variation of the PFN charging voltage. This paper presents the main feature of the klystron-modulator system and the characteristics of the pulsed high-power RF system performance during the beam injection operation for the Pohang Light Source commissioning.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.66.1-66.1
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• 2012

We have developed superconducting mixer receivers for 129 GHz VLBI observation in Korean VLBI Network(KVN). The developed mixer has a radial waveguide probe with simple transmission line LC transformer as a tuning circuit to its 5 series-connected junctions, which can have 125-165 GHz as operation RF frequency. For IF signal path a high impedance quarter-wavelength line connects the probe to one end of symmetric RF chokes. DSB receiver noise of the mixer was about 40 K over 4-6 GHz IF band whereas we achieved about uncorrected SSB noise temperature of 70 K and better than 10 dB IRR in 2SB configuration with 8-10 GHz IF band. Insert-type receiver cartridges using the mixers have been assembled for all three KVN stations. On-site performance summary in commissioning phase is presented.