IPAC2019 - List of Authors (Park, Y.J.)

Paper	Title	Page
THPRB117	Stability and Reliability Issues of PAL-XFEL Modulator	4096
	S.H. Kim, H.-S. Kang, K.H. Kim, H.-S. Lee, C.-K. Min, S.S. Park, Y.J. Park PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: This work is supported by Ministry of Science, ICT(Information/Communication Technology) and Future Planning. The Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) employs 51 units of the pulse modulator in order to obtain the 10 GeV electron beam, which drive one X-band to linearize and 50 S-band klystrons. The PAL-XFEL requires very tight control of the klystron RF phase jitter 0.03-degree for S-band RF, 0.1-degree for X-band RF and the beam voltage stability of below 50 ppm. The RF phase jitter is directly related to the amplitude stability of modulator output pulses. There are several factors to satisfy the stability and reliability for the PAL-XFEL modulator. The largest sources of pulse-to-pulse instability are a current charging power supply (CCPS) for PFN charging, a thyratron switch, and a klystron focusing magnet power supply (MPS). In this paper, the operation and debugging results of those devices are described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB117
About •	paper received ※ 16 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPTS052	Beam Loss Suppression by Beam Matching in Klystron	4218
	S.J. Park, Y.J. Park PAL, Pohang, Kyungbuk, Republic of Korea S.C. Cha, D.H. Kim, D.H. Yu VITZRONEXTECH, Ansan-si, Gyeonggi-do, Republic of Korea J.H. Hwang POSTECH, Pohang, Kyungbuk, Republic of Korea
	Funding: The work was supported by the National R&D Program (grant number: 2016R1A6B2A01016828) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT in Korea. High power klystrons usually employ large cathodes to generate high currents which are compressed inside the gun to provide optimum beam sizes at the cavity section. We compress the beam by using electrostatic and magnetostatic focusing fields which are established by gun electrodes and external magnets respectively. The geometry of the gun elecrodes and the external magnet is carefully designed to meet the matching condition which results in scalloping-free beam. We have established a systematic design procedures to achieve the beam matching condition at arbitrary beam sizes. In this article we report on the beam-matching design and simulation results with an example case of the 80-MW S-band klystron in the Pohang Accelerator Laboratory.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS052
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Stability and Reliability Issues of PAL-XFEL Modulator

4096

S.H. Kim, H.-S. Kang, K.H. Kim, H.-S. Lee, C.-K. Min, S.S. Park, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This work is supported by Ministry of Science, ICT(Information/Communication Technology) and Future Planning.
The Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) employs 51 units of the pulse modulator in order to obtain the 10 GeV electron beam, which drive one X-band to linearize and 50 S-band klystrons. The PAL-XFEL requires very tight control of the klystron RF phase jitter 0.03-degree for S-band RF, 0.1-degree for X-band RF and the beam voltage stability of below 50 ppm. The RF phase jitter is directly related to the amplitude stability of modulator output pulses. There are several factors to satisfy the stability and reliability for the PAL-XFEL modulator. The largest sources of pulse-to-pulse instability are a current charging power supply (CCPS) for PFN charging, a thyratron switch, and a klystron focusing magnet power supply (MPS). In this paper, the operation and debugging results of those devices are described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB117

About •

paper received ※ 16 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPTS052

Beam Loss Suppression by Beam Matching in Klystron

4218

S.J. Park, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
S.C. Cha, D.H. Kim, D.H. Yu
VITZRONEXTECH, Ansan-si, Gyeonggi-do, Republic of Korea
J.H. Hwang
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: The work was supported by the National R&D Program (grant number: 2016R1A6B2A01016828) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT in Korea.
High power klystrons usually employ large cathodes to generate high currents which are compressed inside the gun to provide optimum beam sizes at the cavity section. We compress the beam by using electrostatic and magnetostatic focusing fields which are established by gun electrodes and external magnets respectively. The geometry of the gun elecrodes and the external magnet is carefully designed to meet the matching condition which results in scalloping-free beam. We have established a systematic design procedures to achieve the beam matching condition at arbitrary beam sizes. In this article we report on the beam-matching design and simulation results with an example case of the 80-MW S-band klystron in the Pohang Accelerator Laboratory.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS052

About •

paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)