IPAC2019 - List of Authors (Kang, H.-S.)

Paper	Title	Page
TUYPLM1	XFEL Performance Achieved at PAL-XFEL	1182
	H. Heo, M.-H. Cho, J.H. Han, H.-S. Kang, C. Kim, G. Kim, M.J. Kim, J.H. Ko, H.-S. Lee, C.-K. Min, I.H. Nam, K.-H. Park, C.H. Shim, H. Yang PAL, Pohang, Kyungbuk, Republic of Korea
	The hard X-ray free electron laser at Pohang Accelerator Laboratory (PAL-XFEL) successfully completed the commissioning of SASE and started user operation in late 2016. Since then, the facility has demonstrated excellent stability with very small timing jitter of about 20 fs, and commissioned the self-seeding system over a wide range of photon energies, etc. The talk will provide an overview of the last three years at the PAL-XFEL, including some detailed experimental results, as well as future prospects for the laboratory.
	Slides TUYPLM1 [7.516 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUYPLM1
About •	paper received ※ 20 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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TUPMP032	Design of Analog to Digital Converter Scheme for High - Precision Electromagnet Power supply	1309
	M.J. Kim, Choi. Choi POSTECH, Pohang, Kyungbuk, Republic of Korea J.H. Han, S.-H. Jeong, Y.G. Jung, H.-S. Kang, D.E. Kim, H.-G. Lee, S.B. Lee, S.J. Lee, B.G. Oh, K.-H. Park, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea M.S. Kim Dongguk University, Seoul, Republic of Korea
	This paper deals with the design of an analogue-to-digital converter (ADC) scheme for a highly precise magnet current supply (MPS). The MPSs are requires with stable and precise current specification in range of the ppm. To meet the requirements, the AD circuit is composed of parallel ADCs of low-medium resolution. Digitally, the oversampling and averaging are performed to increase both the effective resolution and the signal to noise ratio (SNR). The implemented AD circuit was improved about 18 dB (32 times oversampling). The MPS applied by the proposed ADC scheme provides more precise control and the stable current within 10 ppm at 200 A. The experiment used a dipole magnet of the PAL-XFEL and its results proved feasibility through precisely measurable DVM3458A (Keysight Co.).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP032
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPGW089	Mechanical Design of a Diamond Crystal Hard X-Ray Self-Seeding Monochromator for PAL-XFEL	3782
	D. Shu, J.W.J. Anton, S.P. Kearney, K. Kim, Yu. Shvyd’ko ANL, Argonne, Illinois, USA H.-S. Kang, C.-K. Min, B.G. Oh, S.Y. Rah PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357 As a part of the Argonne Strategic Partnership Project (SPP) 85H21, a collaboration between Advanced Photon Source (APS), Argonne National Laboratory (ANL) and Pohang Accelerator Laboratory (PAL), we have designed, constructed, and tested a thin-film-diamond monochromator for the PAL X-ray Free-Electron-Laser (PAL-XFEL) hard x-ray self-seeding project. The mechanical design of the PAL-XFEL diamond crystal hard x-ray self-seeding monochromator is based on the APS design of a diamond-crystal monochromator for the LCLS hard x-ray self-seeding project* with enhanced diamond crystal holder for two thin-film-diamond crystals with thicknesses of 30 microns and 100 microns*. The customized high quality thin-film-diamonds and special graphite holder were provided by the Technological Institute for Super-hard and Novel Carbon Materials of Russia (TISNCM), and tested at the APS. An in-vacuum multi-axis precision positioning mechanism is designed to manipulate the duo-thin-film diamonds holder with resolutions and stabilities required by the hard x-ray self-seeding physics. Mechanical specifications, designs, and preliminary test results of the diamond monochromator are presented in this paper. Chang-Ki Min, et al, sub. J. Sync. Rad., 2018 D. Shu, et al, J. Phys.: Conf. Ser. 425 (2013) 052004 Y. Shvyd’ko, et al, FEL2017, Santa Fe ***Polyakov S, et. al, 2011 Diam. Rel. Mat. 20 726
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW089
About •	paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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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
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Paper

Title

Page

XFEL Performance Achieved at PAL-XFEL

1182

H. Heo, M.-H. Cho, J.H. Han, H.-S. Kang, C. Kim, G. Kim, M.J. Kim, J.H. Ko, H.-S. Lee, C.-K. Min, I.H. Nam, K.-H. Park, C.H. Shim, H. Yang
PAL, Pohang, Kyungbuk, Republic of Korea

The hard X-ray free electron laser at Pohang Accelerator Laboratory (PAL-XFEL) successfully completed the commissioning of SASE and started user operation in late 2016. Since then, the facility has demonstrated excellent stability with very small timing jitter of about 20 fs, and commissioned the self-seeding system over a wide range of photon energies, etc. The talk will provide an overview of the last three years at the PAL-XFEL, including some detailed experimental results, as well as future prospects for the laboratory.

Slides TUYPLM1 [7.516 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUYPLM1

About •

paper received ※ 20 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

Export •

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

TUPMP032

Design of Analog to Digital Converter Scheme for High - Precision Electromagnet Power supply

1309

M.J. Kim, Choi. Choi
POSTECH, Pohang, Kyungbuk, Republic of Korea
J.H. Han, S.-H. Jeong, Y.G. Jung, H.-S. Kang, D.E. Kim, H.-G. Lee, S.B. Lee, S.J. Lee, B.G. Oh, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea
M.S. Kim
Dongguk University, Seoul, Republic of Korea

This paper deals with the design of an analogue-to-digital converter (ADC) scheme for a highly precise magnet current supply (MPS). The MPSs are requires with stable and precise current specification in range of the ppm. To meet the requirements, the AD circuit is composed of parallel ADCs of low-medium resolution. Digitally, the oversampling and averaging are performed to increase both the effective resolution and the signal to noise ratio (SNR). The implemented AD circuit was improved about 18 dB (32 times oversampling). The MPS applied by the proposed ADC scheme provides more precise control and the stable current within 10 ppm at 200 A. The experiment used a dipole magnet of the PAL-XFEL and its results proved feasibility through precisely measurable DVM3458A (Keysight Co.).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP032

About •

paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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

THPGW089

Mechanical Design of a Diamond Crystal Hard X-Ray Self-Seeding Monochromator for PAL-XFEL

3782

D. Shu, J.W.J. Anton, S.P. Kearney, K. Kim, Yu. Shvyd’ko
ANL, Argonne, Illinois, USA
H.-S. Kang, C.-K. Min, B.G. Oh, S.Y. Rah
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
As a part of the Argonne Strategic Partnership Project (SPP) 85H21, a collaboration between Advanced Photon Source (APS), Argonne National Laboratory (ANL) and Pohang Accelerator Laboratory (PAL), we have designed, constructed, and tested a thin-film-diamond monochromator for the PAL X-ray Free-Electron-Laser (PAL-XFEL) hard x-ray self-seeding project*. The mechanical design of the PAL-XFEL diamond crystal hard x-ray self-seeding monochromator is based on the APS design of a diamond-crystal monochromator for the LCLS hard x-ray self-seeding project** with enhanced diamond crystal holder for two thin-film-diamond crystals with thicknesses of 30 microns and 100 microns***. The customized high quality thin-film-diamonds and special graphite holder were provided by the Technological Institute for Super-hard and Novel Carbon Materials of Russia (TISNCM)****, and tested at the APS***. An in-vacuum multi-axis precision positioning mechanism is designed to manipulate the duo-thin-film diamonds holder with resolutions and stabilities required by the hard x-ray self-seeding physics. Mechanical specifications, designs, and preliminary test results of the diamond monochromator are presented in this paper.
*Chang-Ki Min, et al, sub. J. Sync. Rad., 2018
**D. Shu, et al, J. Phys.: Conf. Ser. 425 (2013) 052004
***Y. Shvyd’ko, et al, FEL2017, Santa Fe
****Polyakov S, et. al, 2011 Diam. Rel. Mat. 20 726

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW089

About •

paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

Export •

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

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)