FEL2014 - List of Authors (Min, C.-K.)

Paper

Title

Page

Beam Operation of the PAL-XFEL Injector Test Facility

615

J.H. Han, S.Y. Baek, M.S. Chae, H. J. Choi, T. Ha, J.H. Hong, J. Hu, W.H. Hwang, S.H. Jung, H.-S. Kang, C. Kim, C.H. Kim, I.Y. Kim, J.M. Kim, S.H. Kim, I.S. Ko, H.-S. Lee, J. Lee, S.J. Lee, W.W. Lee, C.-K. Min, G. Mun, D.H. Na, S.S. Park, S.J. Park, Y.J. Park, Y.G. Son, H. Yang
PAL, Pohang, Kyungbuk, Republic of Korea

The Pohang Accelerator Laboratory X-ray Free electron Laser (PAL-XFEL) project was launched in 2011. This project aims at the generation of X-ray FEL radiation in a range of 0.1 to 10 nm for photon users with a bunch repetition rate of 60 Hz. The machine consists of a 10 GeV normal conducting S-band linear accelerator and five undulator beamlines. The linac and two undulator beamlines will be constructed by the end of 2015 and first FEL radiation is expected in 2016. As a part of preparation for the project, an Injector Test Facility was constructed in 2012. Since December 2012, beam commissioning is being carried out to find optimum operating conditions and to test accelerator components including RF, laser, diagnostics, magnet, vacuum and control. We present the status of beam commissioning and components tests at the test facility.

Slides WEB02 [10.249 MB]

THB03

Femtosecond-Stability Delivery of Synchronized RF-Signals to the Klystron Gallery over 1-km Optical Fibers

663

J. Kim, K. Jung, J. Lim, J. Shin, H. Yang
KAIST, Daejeon, Republic of Korea
H.-S. Kang, C.-K. Min
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This work was supported by the PAL-XFEL Project and the National Research Foundation (Grant number 2012R1A2A2A01005544) of South Korea.
We present our recent progress in optical frequency comb-based remote optical and RF distribution system at PAL-XFEL. A 238 MHz mode-locked Er-laser is used as an optical master oscillator (OMO), which is stabilized to a 2.856 GHz RF master oscillator (RMO) using a fiber- loop optical-microwave phase detector (FLOM-PD). We partly installed a pair of 1.15 km long fiber links through a cable duct to connect and OMO room to a klystron gallery in the PAL-XFEL Injector Test Facility (ITF). The fiber links are stabilized using balanced optical cross- correlators (BOC). A voltage controlled RF oscillator (VCO) is locked to the delivered optical pulse train using the second FLOM-PD. Residual timing jitter and drift between the two independently distributed optical pulse train and RF signal is measured at the klystron gallery. The results are 6.6 fs rms and 31 fs rms over 7 hours and 62 hours, respectively. This is the first comb-based optical/RF distribution and phase comparison in the klystron gallery environment.

Slides THB03 [7.478 MB]

THP011

Beam Measurement of Photocathode RF-gun for PAL-XFEL

699

J.H. Hong, M.S. Chae, J.H. Han, H.-S. Kang, C.-K. Min, S.J. Park, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea

The Injector Test Facility (ITF) at Pohang Accelerator Laboratory (PAL) was constructed to develop an injector for the PAL X-ray free-electron laser (PAL-XFEL) project. The PAL-XFEL design requires the injector to produce an electron beam with a slice emittance of 0.4 mm-mrad at the charge of 200 pC. A 4-hole type RF-gun has been successfully fabricated and tested at ITF. In this paper we report the recent beam-measurement results using the RF-gun at ITF. Emittance measurements have been carried out by changing laser and RF parameters.

Paper	Title	Page
WEB02	Beam Operation of the PAL-XFEL Injector Test Facility	615
	J.H. Han, S.Y. Baek, M.S. Chae, H. J. Choi, T. Ha, J.H. Hong, J. Hu, W.H. Hwang, S.H. Jung, H.-S. Kang, C. Kim, C.H. Kim, I.Y. Kim, J.M. Kim, S.H. Kim, I.S. Ko, H.-S. Lee, J. Lee, S.J. Lee, W.W. Lee, C.-K. Min, G. Mun, D.H. Na, S.S. Park, S.J. Park, Y.J. Park, Y.G. Son, H. Yang PAL, Pohang, Kyungbuk, Republic of Korea
	The Pohang Accelerator Laboratory X-ray Free electron Laser (PAL-XFEL) project was launched in 2011. This project aims at the generation of X-ray FEL radiation in a range of 0.1 to 10 nm for photon users with a bunch repetition rate of 60 Hz. The machine consists of a 10 GeV normal conducting S-band linear accelerator and five undulator beamlines. The linac and two undulator beamlines will be constructed by the end of 2015 and first FEL radiation is expected in 2016. As a part of preparation for the project, an Injector Test Facility was constructed in 2012. Since December 2012, beam commissioning is being carried out to find optimum operating conditions and to test accelerator components including RF, laser, diagnostics, magnet, vacuum and control. We present the status of beam commissioning and components tests at the test facility.
	Slides WEB02 [10.249 MB]

THB03	Femtosecond-Stability Delivery of Synchronized RF-Signals to the Klystron Gallery over 1-km Optical Fibers	663
	J. Kim, K. Jung, J. Lim, J. Shin, H. Yang KAIST, Daejeon, Republic of Korea H.-S. Kang, C.-K. Min PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: This work was supported by the PAL-XFEL Project and the National Research Foundation (Grant number 2012R1A2A2A01005544) of South Korea. We present our recent progress in optical frequency comb-based remote optical and RF distribution system at PAL-XFEL. A 238 MHz mode-locked Er-laser is used as an optical master oscillator (OMO), which is stabilized to a 2.856 GHz RF master oscillator (RMO) using a fiber- loop optical-microwave phase detector (FLOM-PD). We partly installed a pair of 1.15 km long fiber links through a cable duct to connect and OMO room to a klystron gallery in the PAL-XFEL Injector Test Facility (ITF). The fiber links are stabilized using balanced optical cross- correlators (BOC). A voltage controlled RF oscillator (VCO) is locked to the delivered optical pulse train using the second FLOM-PD. Residual timing jitter and drift between the two independently distributed optical pulse train and RF signal is measured at the klystron gallery. The results are 6.6 fs rms and 31 fs rms over 7 hours and 62 hours, respectively. This is the first comb-based optical/RF distribution and phase comparison in the klystron gallery environment.
	Slides THB03 [7.478 MB]

THP011	Beam Measurement of Photocathode RF-gun for PAL-XFEL	699
	J.H. Hong, M.S. Chae, J.H. Han, H.-S. Kang, C.-K. Min, S.J. Park, Y.J. Park PAL, Pohang, Kyungbuk, Republic of Korea I.S. Ko POSTECH, Pohang, Kyungbuk, Republic of Korea
	The Injector Test Facility (ITF) at Pohang Accelerator Laboratory (PAL) was constructed to develop an injector for the PAL X-ray free-electron laser (PAL-XFEL) project. The PAL-XFEL design requires the injector to produce an electron beam with a slice emittance of 0.4 mm-mrad at the charge of 200 pC. A 4-hole type RF-gun has been successfully fabricated and tested at ITF. In this paper we report the recent beam-measurement results using the RF-gun at ITF. Emittance measurements have been carried out by changing laser and RF parameters.