IPAC2016 - List of Authors (Kang, H.-S.)

Paper	Title	Page
MOPMR001	Micro-mover Development and Test in the PAL-XFEL	229
	B.G. Oh, J.H. Han, H. Heo, J.H. Hong, H.-S. Kang, C. Kim, D.E. Kim, K.-H. Park, Y.J. Suh PAL, Pohang, Republic of Korea
	Two micro-movers, which are able to control the horizontal, vertical and longitudinal positions as well as the yaw and pitch angles remotely, were developed and installed in the PAL-XFEL linac. The solenoid micro-mover in the gun section allows beam-based alignment of an electron beam to the solenoid field and the gun RF field. The X-band cavity micro-mover minimizes the transverse wake field effect caused by transverse misalignment between the beam and X-band cavity. Two micro-movers has similar specifications and the same mechanism, but the sizes are different from each other. In this paper, we present the design, manufacture and test results of the micro-movers.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR001
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MOPMR003	Electron Bunch Length Measurement Using Coherent Radiation Source of fs-THz accelerator at Pohang Accelerator Laboratory	235
SUPSS071	use link to see paper's listing under its alternate paper code
	J.H. Ko, I.S. Ko POSTECH, Pohang, Kyungbuk, Republic of Korea S.H. Jung, H.-S. Kang, I.S. Ko, J. Park PAL, Pohang, Kyungbuk, Republic of Korea
	A Michelson interferometer was installed at the femtosecond (fs) terahertz (THz) Accelerator of Pohang Accelerator Laboratory(PAL) to measure a subpicosecond order electron bunch length. To measure an ultra-short electron bunch length, we use reconstruction process and fast fourier transform. Currently, we are generating THz radiation with the pulse energy of 7μJ by means of coherent transition radiation (CTR) from a 65-MeV electron beam of the fs-THz accelerator. In this paper, we show the how to make a longitudinal distribution of electron bunch and the radiation intensity difference between CTR and Coherent edge radiation (CER) for nondestructive electron bunch length measurement. And we report the measurement methods to get the fine electron bunch length information.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR003
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MOPMY026	Development of an X-Band Linearizer System for PAL-XFEL	554
	H. Heo, J. Hu, H.-S. Kang, K.H. Kim, S.H. Kim, H.-S. Lee, B.G. Oh, S.S. Park, Y.J. Park, Y.J. Suh PAL, Pohang, Republic of Korea
	We developed an X-band RF system for the linear bunch compression in the PAL-XFEL. We installed a SLAC X-band accelerating structure on a precise mover stage and applied RF power by using a SLAC XL-4 11.424 GHz klystron driven by an inverter charging type modulator. We are developing a solid state amplifier controlled by an X-band LLRF system instead of using a TWTA as a driving RF source for the klystron. We present and discuss the recent test results of the system.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY026
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TUOAB01	Optimization of the Dechirper for Electron Bunches of Arbitrary Longitudinal Shapes	1054
SUPSS049	use link to see paper's listing under its alternate paper code
	J.M. Seok, M. Chung UNIST, Ulsan, Republic of Korea J.H. Han, J.H. Hong, H.-S. Kang PAL, Pohang, Kyungbuk, Republic of Korea
	Dechirper is a passive device composed of a vacuum chamber of two corrugated, metallic plates with an adjustable gap. By introducing a small offset in the dechirper with respect to the reference axis, one might generate transverse wakefields and use the dechirper as a deflector. Understanding the interactions between electron beams of various longitudinal shapes with the wakefields generated by the dechirper is important to assess the feasibility of the dechirper for use as a deflector. Recently, using a set of alpha-BBO crystals, shaping of laser pulses and electron bunches on the order of ps is tested at the Injector Test Facility (ITF) of Pohang Accelerator Laboratory (PAL). Furthermore, we have investigated propagation of electron bunches of arbitrary longitudinal shapes through the dechirper. In the numerical simulations, we observed that the arbitrary electron beams were successful deflected except for lethal beam shape problems. Hence, in this work, we study optimization of the dechirper for electron bunches of arbitrary longitudinal shapes, using analytical theory and numerical simulations with the ASTRA and ELEGANT codes.
	Slides TUOAB01 [1.631 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOAB01
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TUPMB013	PAL-XFEL Magnet Design and Magnetic Measurement	1136
	H.S. Suh, S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park PAL, Pohang, Kyungbuk, Republic of Korea
	We have designed and tested magnets for PAL-XFEL of 10GeV in Pohang, Korea. These magnets consist of 6 families of 52 dipole magnets, 11 families of 236 quadrupole magnets, and 4 families of 10⁸ corrector magnets. Two hall probe benches are used to measure the magnetic field. This paper reviews the main parameters of these magnets and the results of magnetic field measurements.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB013
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WEYB01	Diagnostic Systems of the PAL-XFEL	2091
	C. Kim, S.Y. Baek, H. J. Choi, J.H. Hong, H.-S. Kang, G. Kim, J.H. Kim, I.S. Ko, S.J. Lee, G. Mun, B.G. Oh, B.R. Park, D.C. Shin, H. Yang PAL, Pohang, Kyungbuk, Republic of Korea
	The Pohang Accelerator Laboratory (PAL) started an x-ray free electron laser project (PAL-XFEL) in 2011. The construction was finished at the end of 2015 and the commissioning is planned from the beginning of 2016. In the PAL-XFEL, an electron beam with 200 pC will be generated from a photocathode RF gun and will be accelerated to 10 GeV by using a linear accelerator. The electron beam will pass through undulator section to produce hard X-ray radiation. For the successful commissioning and beam operation, various kinds of instruments were prepared.
	Slides WEYB01 [11.770 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEYB01
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WEPMR053	Technical Overview of Cavity BPM Mover for PAL XFEL	2395
	H.-G. Lee, S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, K.W. Kim, S.B. Lee, D.H. Na, B.G. Oh, K.-H. Park, H.S. Suh, Y.J. Suh PAL, Pohang, Republic of Korea
	Pohang Accelerator Laboratory(PAL) has been developing a SASE X-ray Free Electron Laser based on 10 GeV linear accelerator. The cavity BPM mover was developed to be used in the intersections of the Undulator Systems. The main specifications include submicron repeatability for a 50 kg cavity BPM adjusting system within compact dimensions and a ±1.5 mm stroke in the vertical and horizontal direction. Compact linear motion guide based on 5-phase stepping motors have been chosen. A closed-loop control system has been developed to achieve this repeatability. For the feedback, one digital probe sensor for each axis was used. Mechanical switches are used to limit movement. In addition, hard-stops are included for emergency. In this report, we describe the design of the stages used for precise movement and results of mechanical measurements including reproducibility will be reported.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR053
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WEPOR015	Introduction to WPS System Designed to Measure the Change of Location for PAL-XFEL Girder	2693
	H. J. Choi, K.H. Gil, H.-S. Kang, H.-G. Lee, S.B. Lee, K.W. Seo PAL, Pohang, Kyungbuk, Republic of Korea
	To maintain stable electron beam parameters (Energy 10GeV, Charge 200pC, Bunch Length 60fs, Emittance X/Y 0.481um/0.256um), PAL-XFEL equipment should keep the alignment of accelerator (±100um) and undulator (±50um) constant. To ensure the precise measurement and alignment of PAL-XFEL, GPS-based surface geodetic network and the installation of a tunnel measurement network inside buildings was prepared and the fiducialization of major equipment was completed. After PAL-XFEL equipment is aligned, if the ground and buildings go through vertical changes during operation, tilt and misalignment of equipments (correct magnet, BPM, accelerator) will cause errors in the electron beam trajectory, which will lead to changes in the beam parameter. Hydrostatic Levelling System (HLS) was installed to measure vertical changes in buildings and the ground (sinking and uplifting) continuously and systematically, and Wire Position System (WPS) installed to measure changes in Girder. This paper introduces the operation principle, design concept, installation status, and operation status of WPS.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR015
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WEPOR040	LLRF Development for PAL-XFEL	2761
	J. Hu, W.H. Hwang, H.-S. Kang, H.-S. Lee, C.-K. Min, G. Mun PAL, Pohang, Kyungbuk, Republic of Korea J.H. Chang, J.S. Han, Y.S. Kim RFPT, Gyeonggi-do, Republic of Korea O.J. Kim, H.S. Lee Mobiis Co., Ltd., Seoul, Republic of Korea
	PAL-XFEL construction is completed. Now, beam commissioning is ongoing after RF conditioning. The LLRF and SSA systems installed and in normal operation are presented. Those structures, features, characteristics, and performances are described.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR040
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THOBB01	PAL-XFEL Linac RF System	3192
	H.-S. Lee, H. Heo, J. Hu, H.-S. Kang, K.W. Kim, K.H. Kim, S.H. Kim, I.S. Ko, S.S. Park, Y.J. Park PAL, Pohang, Kyungbuk, Republic of Korea H. Matsumoto KEK, Tokai, Ibaraki, Japan
	The PAL-XFEL hard X-ray linac has a 716 m long gallery and tunnel for 10 GeV. Forty nine modulators are necessary in the hard X-ray gallery for an X-band linearizer, an S-band RF gun, two S-band deflectors and 45 S-band klystrons for accelerating structures. They have been installed completely from March 15, 2015 to December 30, 2015 after completing the building construction. There are 51 modulators, 178 accelerators structures, 42 SLEDs in the hard X-ray linac and the soft X-ray linac. The RF conditioning of the klystrons, SLEDs and accelerating structures were stated from November 24, 2015. We describe the PAL-XFEL system and the current status of the linac RF system.
	Slides THOBB01 [22.023 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THOBB01
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THPMW010	PAL-XFEL Dipole Magnet Power Supplies	3555
	S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, D.H. Na, B.G. Oh, K.-H. Park, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea
	Total 632 magnet power supplies (MPSs) are under operating in PAL-XFEL. These magnet power supplies can be categorized as three types - corrector, quadrupole and dipole. The dipole MPSs are ranging from 110A/80V bipolar PS to 310A/200V unipolar PS. The long term stability of bipolar power supply is 10 ppm with 250 A 40V output for gun solenoid. The three types of dipole MPSs are developed for PAL-XFEL. Precise measurement results show that all power supplies meet the required specifications. The long term operation stability of the MPSs are appeared to be sufficient for a stable operation of the PAL-XFEL.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW010
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THPMW012	The Fast Interlock Controller for High Power Pulse Modulator at PAL-XFEL	3561
	S.H. Kim, H.-S. Kang, K.H. Kim, S.J. Kwon, H.-S. Lee, S.S. Park, Y.J. Park PAL, Pohang, Kyungbuk, Republic of Korea I.S. Ko POSTECH, Pohang, Kyungbuk, Republic of Korea
	Funding: This work is supported by Ministry of Science, ICT(Information/Communication Technology) and Future Planning. The modulator control system for PAL-XFEL consists of a PLC unit (Programmable Logic Controller) and FPSCM (Fast Pulse Signal Conditioning Module). There are two kinds of interlock, which are dynamic and static interlocks categorized as analogue monitor and control signals, digital monitor and control signals. In case of dynamic interlocks, the internal interface of the PLC unit had to be modified due to operating within 10 ms time response from the interlock event. The fast pulse signal conditioning module is adopted for preconditioning the fast pulse and DC signals that inherently have high noise levels generated from a beam voltage, a beam current and EOLC current. Those EM (Electro-Magnetic) noises are generated by thyratron switching. The amplitude of the thyratron noise is large which causes the problem at the control devices, frequently. In this paper, the test results of the interlock control system will be described.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW012
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THPOW045	Development of PAL-XFEL Undulator System	4044
	D.E. Kim, Y.-G. Jung, H.-S. Kang, I.S. Ko, H.-G. Lee, S.B. Lee, W.W. Lee, B.G. Oh, K.-H. Park, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea J. Pflüger XFEL. EU, Hamburg, Germany
	Pohang Accelerator Laboratory (PAL) is developing a 0.1 nm SASE based FEL based on 10 GeV S-band linear accelerator named PAL-XFEL. At the first stage, PAL-XFEL needs two undulator lines for photon source. The hard X-ray undulator line requires 20 units of 5 m long hybrid-type conventional planar undulator and soft X-ray line requires 7 units of 5 m long hybrid type planar undulators. PAL is developing undulator magnetic structure based on EU-XFEL concepts. In this report, the results of final pole height tuning results, and magnetic measurement results will be presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW045
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THPOY057	RF Timing Distribution and Laser Synchronization Commissioning of PAL-XFEL	4234
	C.-K. Min, S.H. Jung, H.-S. Kang, C. Kim, I.S. Ko, S.J. Park PAL, Pohang, Kyungbuk, Republic of Korea
	PAL-XFEL requires <100 fs synchronization of LLRF systems and optical lasers for stable operation and even lower jitter is favorable in higher performance and pump-probe experiments. The RF timing distribution system is based on a 476 MHz reference line, which is converted to 2.856 GHz at 16 locations over 1.5 km distance using phase-locked DRO. The 2.856 GHz signals are amplified and split to 10 outputs, which is connected to LLRFs, BAMs, and DCMs through low timing drift cables. The jitter between two different PLDRO units is estimated to ~1 fs from 1 Hz to 1 MHz. The synchronization jitter between a Ti:sapphire laser and the 2.856 GHz signal is measured less than 20 fs.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY057
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Paper

Title

Page

Micro-mover Development and Test in the PAL-XFEL

229

B.G. Oh, J.H. Han, H. Heo, J.H. Hong, H.-S. Kang, C. Kim, D.E. Kim, K.-H. Park, Y.J. Suh
PAL, Pohang, Republic of Korea

Two micro-movers, which are able to control the horizontal, vertical and longitudinal positions as well as the yaw and pitch angles remotely, were developed and installed in the PAL-XFEL linac. The solenoid micro-mover in the gun section allows beam-based alignment of an electron beam to the solenoid field and the gun RF field. The X-band cavity micro-mover minimizes the transverse wake field effect caused by transverse misalignment between the beam and X-band cavity. Two micro-movers has similar specifications and the same mechanism, but the sizes are different from each other. In this paper, we present the design, manufacture and test results of the micro-movers.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR001

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MOPMR003

Electron Bunch Length Measurement Using Coherent Radiation Source of fs-THz accelerator at Pohang Accelerator Laboratory

235

SUPSS071

use link to see paper's listing under its alternate paper code

J.H. Ko, I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea
S.H. Jung, H.-S. Kang, I.S. Ko, J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

A Michelson interferometer was installed at the femtosecond (fs) terahertz (THz) Accelerator of Pohang Accelerator Laboratory(PAL) to measure a subpicosecond order electron bunch length. To measure an ultra-short electron bunch length, we use reconstruction process and fast fourier transform. Currently, we are generating THz radiation with the pulse energy of 7μJ by means of coherent transition radiation (CTR) from a 65-MeV electron beam of the fs-THz accelerator. In this paper, we show the how to make a longitudinal distribution of electron bunch and the radiation intensity difference between CTR and Coherent edge radiation (CER) for nondestructive electron bunch length measurement. And we report the measurement methods to get the fine electron bunch length information.

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MOPMY026

Development of an X-Band Linearizer System for PAL-XFEL

554

H. Heo, J. Hu, H.-S. Kang, K.H. Kim, S.H. Kim, H.-S. Lee, B.G. Oh, S.S. Park, Y.J. Park, Y.J. Suh
PAL, Pohang, Republic of Korea

We developed an X-band RF system for the linear bunch compression in the PAL-XFEL. We installed a SLAC X-band accelerating structure on a precise mover stage and applied RF power by using a SLAC XL-4 11.424 GHz klystron driven by an inverter charging type modulator. We are developing a solid state amplifier controlled by an X-band LLRF system instead of using a TWTA as a driving RF source for the klystron. We present and discuss the recent test results of the system.

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TUOAB01

Optimization of the Dechirper for Electron Bunches of Arbitrary Longitudinal Shapes

1054

SUPSS049

use link to see paper's listing under its alternate paper code

J.M. Seok, M. Chung
UNIST, Ulsan, Republic of Korea
J.H. Han, J.H. Hong, H.-S. Kang
PAL, Pohang, Kyungbuk, Republic of Korea

Dechirper is a passive device composed of a vacuum chamber of two corrugated, metallic plates with an adjustable gap. By introducing a small offset in the dechirper with respect to the reference axis, one might generate transverse wakefields and use the dechirper as a deflector. Understanding the interactions between electron beams of various longitudinal shapes with the wakefields generated by the dechirper is important to assess the feasibility of the dechirper for use as a deflector. Recently, using a set of alpha-BBO crystals, shaping of laser pulses and electron bunches on the order of ps is tested at the Injector Test Facility (ITF) of Pohang Accelerator Laboratory (PAL). Furthermore, we have investigated propagation of electron bunches of arbitrary longitudinal shapes through the dechirper. In the numerical simulations, we observed that the arbitrary electron beams were successful deflected except for lethal beam shape problems. Hence, in this work, we study optimization of the dechirper for electron bunches of arbitrary longitudinal shapes, using analytical theory and numerical simulations with the ASTRA and ELEGANT codes.

Slides TUOAB01 [1.631 MB]

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TUPMB013

PAL-XFEL Magnet Design and Magnetic Measurement

1136

H.S. Suh, S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park
PAL, Pohang, Kyungbuk, Republic of Korea

We have designed and tested magnets for PAL-XFEL of 10GeV in Pohang, Korea. These magnets consist of 6 families of 52 dipole magnets, 11 families of 236 quadrupole magnets, and 4 families of 10⁸ corrector magnets. Two hall probe benches are used to measure the magnetic field. This paper reviews the main parameters of these magnets and the results of magnetic field measurements.

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WEYB01

Diagnostic Systems of the PAL-XFEL

2091

C. Kim, S.Y. Baek, H. J. Choi, J.H. Hong, H.-S. Kang, G. Kim, J.H. Kim, I.S. Ko, S.J. Lee, G. Mun, B.G. Oh, B.R. Park, D.C. Shin, H. Yang
PAL, Pohang, Kyungbuk, Republic of Korea

The Pohang Accelerator Laboratory (PAL) started an x-ray free electron laser project (PAL-XFEL) in 2011. The construction was finished at the end of 2015 and the commissioning is planned from the beginning of 2016. In the PAL-XFEL, an electron beam with 200 pC will be generated from a photocathode RF gun and will be accelerated to 10 GeV by using a linear accelerator. The electron beam will pass through undulator section to produce hard X-ray radiation. For the successful commissioning and beam operation, various kinds of instruments were prepared.

Slides WEYB01 [11.770 MB]

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WEPMR053

Technical Overview of Cavity BPM Mover for PAL XFEL

2395

H.-G. Lee, S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, K.W. Kim, S.B. Lee, D.H. Na, B.G. Oh, K.-H. Park, H.S. Suh, Y.J. Suh
PAL, Pohang, Republic of Korea

Pohang Accelerator Laboratory(PAL) has been developing a SASE X-ray Free Electron Laser based on 10 GeV linear accelerator. The cavity BPM mover was developed to be used in the intersections of the Undulator Systems. The main specifications include submicron repeatability for a 50 kg cavity BPM adjusting system within compact dimensions and a ±1.5 mm stroke in the vertical and horizontal direction. Compact linear motion guide based on 5-phase stepping motors have been chosen. A closed-loop control system has been developed to achieve this repeatability. For the feedback, one digital probe sensor for each axis was used. Mechanical switches are used to limit movement. In addition, hard-stops are included for emergency. In this report, we describe the design of the stages used for precise movement and results of mechanical measurements including reproducibility will be reported.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR053

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WEPOR015

Introduction to WPS System Designed to Measure the Change of Location for PAL-XFEL Girder

2693

H. J. Choi, K.H. Gil, H.-S. Kang, H.-G. Lee, S.B. Lee, K.W. Seo
PAL, Pohang, Kyungbuk, Republic of Korea

To maintain stable electron beam parameters (Energy 10GeV, Charge 200pC, Bunch Length 60fs, Emittance X/Y 0.481um/0.256um), PAL-XFEL equipment should keep the alignment of accelerator (±100um) and undulator (±50um) constant. To ensure the precise measurement and alignment of PAL-XFEL, GPS-based surface geodetic network and the installation of a tunnel measurement network inside buildings was prepared and the fiducialization of major equipment was completed. After PAL-XFEL equipment is aligned, if the ground and buildings go through vertical changes during operation, tilt and misalignment of equipments (correct magnet, BPM, accelerator) will cause errors in the electron beam trajectory, which will lead to changes in the beam parameter. Hydrostatic Levelling System (HLS) was installed to measure vertical changes in buildings and the ground (sinking and uplifting) continuously and systematically, and Wire Position System (WPS) installed to measure changes in Girder. This paper introduces the operation principle, design concept, installation status, and operation status of WPS.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR015

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WEPOR040

LLRF Development for PAL-XFEL

2761

J. Hu, W.H. Hwang, H.-S. Kang, H.-S. Lee, C.-K. Min, G. Mun
PAL, Pohang, Kyungbuk, Republic of Korea
J.H. Chang, J.S. Han, Y.S. Kim
RFPT, Gyeonggi-do, Republic of Korea
O.J. Kim, H.S. Lee
Mobiis Co., Ltd., Seoul, Republic of Korea

PAL-XFEL construction is completed. Now, beam commissioning is ongoing after RF conditioning. The LLRF and SSA systems installed and in normal operation are presented. Those structures, features, characteristics, and performances are described.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR040

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THOBB01

PAL-XFEL Linac RF System

3192

H.-S. Lee, H. Heo, J. Hu, H.-S. Kang, K.W. Kim, K.H. Kim, S.H. Kim, I.S. Ko, S.S. Park, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
H. Matsumoto
KEK, Tokai, Ibaraki, Japan

The PAL-XFEL hard X-ray linac has a 716 m long gallery and tunnel for 10 GeV. Forty nine modulators are necessary in the hard X-ray gallery for an X-band linearizer, an S-band RF gun, two S-band deflectors and 45 S-band klystrons for accelerating structures. They have been installed completely from March 15, 2015 to December 30, 2015 after completing the building construction. There are 51 modulators, 178 accelerators structures, 42 SLEDs in the hard X-ray linac and the soft X-ray linac. The RF conditioning of the klystrons, SLEDs and accelerating structures were stated from November 24, 2015. We describe the PAL-XFEL system and the current status of the linac RF system.

Slides THOBB01 [22.023 MB]

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THPMW010

PAL-XFEL Dipole Magnet Power Supplies

3555

S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, D.H. Na, B.G. Oh, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea

Total 632 magnet power supplies (MPSs) are under operating in PAL-XFEL. These magnet power supplies can be categorized as three types - corrector, quadrupole and dipole. The dipole MPSs are ranging from 110A/80V bipolar PS to 310A/200V unipolar PS. The long term stability of bipolar power supply is 10 ppm with 250 A 40V output for gun solenoid. The three types of dipole MPSs are developed for PAL-XFEL. Precise measurement results show that all power supplies meet the required specifications. The long term operation stability of the MPSs are appeared to be sufficient for a stable operation of the PAL-XFEL.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW010

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THPMW012

The Fast Interlock Controller for High Power Pulse Modulator at PAL-XFEL

3561

S.H. Kim, H.-S. Kang, K.H. Kim, S.J. Kwon, H.-S. Lee, S.S. Park, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: This work is supported by Ministry of Science, ICT(Information/Communication Technology) and Future Planning.
The modulator control system for PAL-XFEL consists of a PLC unit (Programmable Logic Controller) and FPSCM (Fast Pulse Signal Conditioning Module). There are two kinds of interlock, which are dynamic and static interlocks categorized as analogue monitor and control signals, digital monitor and control signals. In case of dynamic interlocks, the internal interface of the PLC unit had to be modified due to operating within 10 ms time response from the interlock event. The fast pulse signal conditioning module is adopted for preconditioning the fast pulse and DC signals that inherently have high noise levels generated from a beam voltage, a beam current and EOLC current. Those EM (Electro-Magnetic) noises are generated by thyratron switching. The amplitude of the thyratron noise is large which causes the problem at the control devices, frequently. In this paper, the test results of the interlock control system will be described.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW012

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THPOW045

Development of PAL-XFEL Undulator System

4044

D.E. Kim, Y.-G. Jung, H.-S. Kang, I.S. Ko, H.-G. Lee, S.B. Lee, W.W. Lee, B.G. Oh, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea
J. Pflüger
XFEL. EU, Hamburg, Germany

Pohang Accelerator Laboratory (PAL) is developing a 0.1 nm SASE based FEL based on 10 GeV S-band linear accelerator named PAL-XFEL. At the first stage, PAL-XFEL needs two undulator lines for photon source. The hard X-ray undulator line requires 20 units of 5 m long hybrid-type conventional planar undulator and soft X-ray line requires 7 units of 5 m long hybrid type planar undulators. PAL is developing undulator magnetic structure based on EU-XFEL concepts. In this report, the results of final pole height tuning results, and magnetic measurement results will be presented.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW045

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THPOY057

RF Timing Distribution and Laser Synchronization Commissioning of PAL-XFEL

4234

C.-K. Min, S.H. Jung, H.-S. Kang, C. Kim, I.S. Ko, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

PAL-XFEL requires <100 fs synchronization of LLRF systems and optical lasers for stable operation and even lower jitter is favorable in higher performance and pump-probe experiments. The RF timing distribution system is based on a 476 MHz reference line, which is converted to 2.856 GHz at 16 locations over 1.5 km distance using phase-locked DRO. The 2.856 GHz signals are amplified and split to 10 outputs, which is connected to LLRFs, BAMs, and DCMs through low timing drift cables. The jitter between two different PLDRO units is estimated to ~1 fs from 1 Hz to 1 MHz. The synchronization jitter between a Ti:sapphire laser and the 2.856 GHz signal is measured less than 20 fs.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY057

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