IPAC2012 - List of Authors (Joo, Y.D.)

Paper

Title

Page

Injection Transient Motion at PLS-II

688

I. Hwang, T. Ha, Y.D. Joo, C. Kim, M. Kim, S.H. Kim, B.-J. Lee, E.H. Lee, S. Shin
PAL, Pohang, Kyungbuk, Republic of Korea

PLS-II is an upgraded third generation synchrotron which includes many insertion devices with improved beam properties. Top-up operation is short time-interval injection to make roughly constant current and is essential to provide high intensity beam. When the electrons are injected to synchrotron, the stored beam is disturbed by small error of the injection system and the beam quality at the beamline can be decreased. We present this injection transient motion at PLS-II.

TUOBB02

Commissioning of the PLS-II

1089

S. Shin, J.Y. Choi, T. Ha, J.Y. Huang, I. Hwang, W.H. Hwang, Y.D. Joo, C. Kim, D.T. Kim, D.E. Kim, J.M. Kim, M. Kim, S.H. Kim, S.-C. Kim, S.J. Kwon, B.-J. Lee, E.H. Lee, H.-S. Lee, H.M. Lee, J.W. Lee, S.H. Nam, E.S. Park, I.S. Park, S.S. Park, S.J. Park, Y.G. Son, J.C. Yoon
PAL, Pohang, Kyungbuk, Republic of Korea
J-Y. Kim, B.H. Oh
KAERI, Daejon, Republic of Korea
J. Lee
POSTECH, Pohang, Kyungbuk, Republic of Korea

The Pohang Light Source (PLS) has operated for 14 years successfully. To meet the request of the increasing user community, the PLS-II that is the upgrade project of PLS has been completed. Main goals of the PLS-II are to increase beam energy to 3 GeV, to increase number of insertion devices by the factor of two (20 IDs), to increase beam current to 400 mA and to reduce beam emittance below 10 nm with existing PLS tunnel and injection system. The PLS-II had been commissioned over the six months. During commissioning, we achieved 14 insertion devices operation and top-up operation with 100 mA beam current and 5.8 nm beam emittance. In this presentation, we report the experimental results from the PLS-II commissioning.

Slides TUOBB02 [3.484 MB]

WEPPC023

Status and Progress of RF System for the PLS-II Storage Ring

2254

M.-H. Chun, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, C.D. Park, H.J. Park, I.S. Park, Y.U. Sohn, I.H. Yu
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: Supported by the Korea Ministry of Science and Technology
The RF system for the Pohang Light Source (PLS) storage ring was upgraded for PLS-II project of 3.0GeV/400mA from 2.5GeV/200mA. the RF system is commissioning with five normal conducting(NC) RF cavities at total maximum RF power of 280kW to the cavities with two 300kW klystron and two 75kW klystron amplifiers in 2011. The super conducting(SC) cavities will be installed on August 2012 because of long delivery. Therefore three NC RF cavities will be replaced with two SC cavities with cryomodules, and operated with cryogenics, digital low level, and 300kW klystron high power system. Also we are preparing the third SC cavity stand to increase the storage ring current up to 400mA with all insertion devices operation. This paper describes the present installation, commissioning, operation status, upgrade progress, and future plan of the RF system for the upgraded project of PLS-II storage ring.

WEPPC024

Preliminary Test of Superconducting RF Cavities for PLS-II

2257

Y.U. Sohn, M.-H. Chun, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, S.H. Nam, C.D. Park, H.J. Park, I.S. Park, I.H. Yu
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This project is supported by the Korea Ministry of Science and Technology.
The main part of the Installation for the PLS-II upgrade was finished in June and is on the way to user operation through elaborate commissioning. Up to now, the achievement is 150 mA beam current at 3 GeV with multi-bunch mode with 5 normal conducting cavities which served in the PLS before. After installation of 2 SRF cavities in the summer of 2012, the PLS-II will have 300 mA beam current with 20 IDs by 2 superconducting RF cavities until July, 2014. Finally, one more superconducting cavity will be added in August, 2014, and beam current will rise to 400 mA. The two SRF cavities are under test and conditioning. The two main subsystems, SRF cavities and ceramic windows were tested independently to confirm their performance. Each cavity recorded its accelerating voltage as 3.27 MV and 3.24 MV at 4.2K, respectively. Two RF windows also passed their specification, 300 kW CW traveling wave and 150 kW CW standing wave. The preliminary tests of SRF cryomodules are reported in the presentation.

WEPPD069

PLS-II Linac Upgrade

2681

B.-J. Lee, J.Y. Choi, S. Chunjarean, T. Ha, J.Y. Huang, I. Hwang, Y.D. Joo, C. Kim, M. Kim, S.H. Kim, S.J. Kwon, S.H. Nam, S.S. Park, S.J. Park, S. Shin, Y.G. Son
PAL, Pohang, Kyungbuk, Republic of Korea

This paper reports on the recent status of the Pohang Light Source (PLS)-II linac at Pohang Accelerator Laboratory (PAL). From 2009, the linac upgrade has been started increasing its energy from 2.5 GeV to 3 GeV aiming stable top-up mode operation. First, we show that the stability status of the two different types of modulators to meet the top-up condition which requires very stable modulator system in linac. Next, we introduce upgrade status those differ from their PLS (2.5 GeV) such as installation of the dual vacuum systems for the electron gun to replace it immediately, adding important diagnostic tools, and reutilization of the beam analysis system just after pre-injector. Finally we present the electron beam parameters measured by those diagnostic system.

THPPC057

S-band High Power RF System for 10 GeV PAL-XFEL

3419

W.H. Hwang, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, S.H. Kim, H.-S. Lee, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

In PAL, We are constructing a 10GeV PxFEL project. The output power of the klystron is 80 MW at the pulse width of 4 ㎲ and the repetition rate of 120 Hz. In high power operation, it is important to decrease the rf electric field to protect rf break-down in high power rf components. To obtain the maximum beam, we must reduce the phase difference between waveguide branches including accelerating structure and minimize the environment influences. This paper describes the waveguide system and high power rf components for the PxFEL.

THPPC059

Design of SLED System with Dual Side-wall Coupling Irises and Biplanar Power Splitter for PAL XFEL

3425

Y.D. Joo, I. Hwang, C. Kim, B.-J. Lee
PAL, Pohang, Kyungbuk, Republic of Korea

The SLED system of the PAL XFEL is required to be operated with the RF input power of 80 MW and the pulse width of 4 us. The high RF dose from the RF breakdown at the coupling holes and power splitter prohibits that the original design of the SLED serve this operation condition. To reduce the gradient at the cavity coupling structure, the concept of dual side-wall coupling irises is introduced. In addition, the 3dB splitter is modified with the concept of biplanar coupler structure.

Paper	Title	Page
MOPPP056	Injection Transient Motion at PLS-II	688
	I. Hwang, T. Ha, Y.D. Joo, C. Kim, M. Kim, S.H. Kim, B.-J. Lee, E.H. Lee, S. Shin PAL, Pohang, Kyungbuk, Republic of Korea
	PLS-II is an upgraded third generation synchrotron which includes many insertion devices with improved beam properties. Top-up operation is short time-interval injection to make roughly constant current and is essential to provide high intensity beam. When the electrons are injected to synchrotron, the stored beam is disturbed by small error of the injection system and the beam quality at the beamline can be decreased. We present this injection transient motion at PLS-II.

TUOBB02	Commissioning of the PLS-II	1089
	S. Shin, J.Y. Choi, T. Ha, J.Y. Huang, I. Hwang, W.H. Hwang, Y.D. Joo, C. Kim, D.T. Kim, D.E. Kim, J.M. Kim, M. Kim, S.H. Kim, S.-C. Kim, S.J. Kwon, B.-J. Lee, E.H. Lee, H.-S. Lee, H.M. Lee, J.W. Lee, S.H. Nam, E.S. Park, I.S. Park, S.S. Park, S.J. Park, Y.G. Son, J.C. Yoon PAL, Pohang, Kyungbuk, Republic of Korea J-Y. Kim, B.H. Oh KAERI, Daejon, Republic of Korea J. Lee POSTECH, Pohang, Kyungbuk, Republic of Korea
	The Pohang Light Source (PLS) has operated for 14 years successfully. To meet the request of the increasing user community, the PLS-II that is the upgrade project of PLS has been completed. Main goals of the PLS-II are to increase beam energy to 3 GeV, to increase number of insertion devices by the factor of two (20 IDs), to increase beam current to 400 mA and to reduce beam emittance below 10 nm with existing PLS tunnel and injection system. The PLS-II had been commissioned over the six months. During commissioning, we achieved 14 insertion devices operation and top-up operation with 100 mA beam current and 5.8 nm beam emittance. In this presentation, we report the experimental results from the PLS-II commissioning.
	Slides TUOBB02 [3.484 MB]

WEPPC023	Status and Progress of RF System for the PLS-II Storage Ring	2254
	M.-H. Chun, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, C.D. Park, H.J. Park, I.S. Park, Y.U. Sohn, I.H. Yu PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: Supported by the Korea Ministry of Science and Technology The RF system for the Pohang Light Source (PLS) storage ring was upgraded for PLS-II project of 3.0GeV/400mA from 2.5GeV/200mA. the RF system is commissioning with five normal conducting(NC) RF cavities at total maximum RF power of 280kW to the cavities with two 300kW klystron and two 75kW klystron amplifiers in 2011. The super conducting(SC) cavities will be installed on August 2012 because of long delivery. Therefore three NC RF cavities will be replaced with two SC cavities with cryomodules, and operated with cryogenics, digital low level, and 300kW klystron high power system. Also we are preparing the third SC cavity stand to increase the storage ring current up to 400mA with all insertion devices operation. This paper describes the present installation, commissioning, operation status, upgrade progress, and future plan of the RF system for the upgraded project of PLS-II storage ring.

WEPPC024	Preliminary Test of Superconducting RF Cavities for PLS-II	2257
	Y.U. Sohn, M.-H. Chun, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, S.H. Nam, C.D. Park, H.J. Park, I.S. Park, I.H. Yu PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: This project is supported by the Korea Ministry of Science and Technology. The main part of the Installation for the PLS-II upgrade was finished in June and is on the way to user operation through elaborate commissioning. Up to now, the achievement is 150 mA beam current at 3 GeV with multi-bunch mode with 5 normal conducting cavities which served in the PLS before. After installation of 2 SRF cavities in the summer of 2012, the PLS-II will have 300 mA beam current with 20 IDs by 2 superconducting RF cavities until July, 2014. Finally, one more superconducting cavity will be added in August, 2014, and beam current will rise to 400 mA. The two SRF cavities are under test and conditioning. The two main subsystems, SRF cavities and ceramic windows were tested independently to confirm their performance. Each cavity recorded its accelerating voltage as 3.27 MV and 3.24 MV at 4.2K, respectively. Two RF windows also passed their specification, 300 kW CW traveling wave and 150 kW CW standing wave. The preliminary tests of SRF cryomodules are reported in the presentation.

WEPPD069	PLS-II Linac Upgrade	2681
	B.-J. Lee, J.Y. Choi, S. Chunjarean, T. Ha, J.Y. Huang, I. Hwang, Y.D. Joo, C. Kim, M. Kim, S.H. Kim, S.J. Kwon, S.H. Nam, S.S. Park, S.J. Park, S. Shin, Y.G. Son PAL, Pohang, Kyungbuk, Republic of Korea
	This paper reports on the recent status of the Pohang Light Source (PLS)-II linac at Pohang Accelerator Laboratory (PAL). From 2009, the linac upgrade has been started increasing its energy from 2.5 GeV to 3 GeV aiming stable top-up mode operation. First, we show that the stability status of the two different types of modulators to meet the top-up condition which requires very stable modulator system in linac. Next, we introduce upgrade status those differ from their PLS (2.5 GeV) such as installation of the dual vacuum systems for the electron gun to replace it immediately, adding important diagnostic tools, and reutilization of the beam analysis system just after pre-injector. Finally we present the electron beam parameters measured by those diagnostic system.

THPPC057	S-band High Power RF System for 10 GeV PAL-XFEL	3419
	W.H. Hwang, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, S.H. Kim, H.-S. Lee, Y.J. Park PAL, Pohang, Kyungbuk, Republic of Korea
	In PAL, We are constructing a 10GeV PxFEL project. The output power of the klystron is 80 MW at the pulse width of 4 ㎲ and the repetition rate of 120 Hz. In high power operation, it is important to decrease the rf electric field to protect rf break-down in high power rf components. To obtain the maximum beam, we must reduce the phase difference between waveguide branches including accelerating structure and minimize the environment influences. This paper describes the waveguide system and high power rf components for the PxFEL.

THPPC059	Design of SLED System with Dual Side-wall Coupling Irises and Biplanar Power Splitter for PAL XFEL	3425
	Y.D. Joo, I. Hwang, C. Kim, B.-J. Lee PAL, Pohang, Kyungbuk, Republic of Korea
	The SLED system of the PAL XFEL is required to be operated with the RF input power of 80 MW and the pulse width of 4 us. The high RF dose from the RF breakdown at the coupling holes and power splitter prohibits that the original design of the SLED serve this operation condition. To reduce the gradient at the cavity coupling structure, the concept of dual side-wall coupling irises is introduced. In addition, the 3dB splitter is modified with the concept of biplanar coupler structure.