IPAC2017 - List of Authors (Qian, H.J.)

Paper	Title	Page
TUPIK051	Statistics on High Average Power Operation and Results from the Electron Beam Characterization at PITZ	1806
	Y. Renier, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, T. Rublack, C. Saisa-ard, F. Stephan, Q.T. Zhao DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria M. Bousonville, S. Choroba, S. Lederer DESY, Hamburg, Germany
	The Photo Injector Test Facility at DESY in Zeuthen (PITZ) develops, tests and characterizes high brightness electron sources for FLASH and European XFEL. Since these FELs work with superconducting accelerators in pulsed mode, also the corresponding normal-conducting RF gun has to operate with long RF pulses. Generating high beam quality from the photo-cathode RF gun in addition requires a high accelerating gradient at the cathode. Therefore, the RF gun has to ensure stable and reliable operation at high average RF power, e.g. 6.5 MW peak power in the gun for 650 μs RF pulse length and 10 Hz repetition rate for the European XFEL. Several RF gun setups have been operated towards these goals over the last years. The latest gun setup is in operation since March 2016 and includes RF Gun 4.6 with an improved contact spring design. The RF input distribution consists of a coaxial coupler, a T-combiner and 2 RF windows from DESY production. In this contribution we will present statistics on the high average power operation and results from the characterization of the produced electron beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK051
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WEPAB033	Experimental Optimization and Characterization of Electron Beams for Generating IR/THz SASE FEL Radiation with PITZ	2650
	P. Boonpornprasert, Y. Chen, J.D. Good, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, T. Rublack, F. Stephan DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria C. Saisa-ard Chiang Mai University, Chiang Mai, Thailand Q.T. Zhao IMP/CAS, Lanzhou, People's Republic of China
	The Photo Injector Test facility at DESY, Zeuthen site (PITZ), develops high brightness electron sources for modern linac-based Free Electron Lasers (FELs). The PITZ accelerator can also be considered as a suitable machine for the development of an IR/THz source prototype for pump-probe experiments at the European XFEL. One of the interesting options for the IR/THz generation with PITZ is to generate the radiation by means of a SASE FEL using an uncompressed electron beam with bunch length of a few 10 ps and a peak current of ~200 A. In this paper, results of experimental optimizations and characterizations, including transverse phase space, slice transverse emittance and longitudinal phase space, of electron beams with bunch charges of 4 nC are presented and discussed. The measurements were done with beam momenta of 15 MeV/c and 22 MeV/c. Results of IR/THz SASE FEL calculations by using the GENESIS1.3 code based on the measured beam parameters are also presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB033
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WEPAB122	Experimental Demonstration of Ballistic Bunching with Dielectric-Lined Waveguides at Pitz	2857
	F. Lemery University of Hamburg, Hamburg, Germany G.A. Amatuni, B. Grigoryan CANDLE, Yerevan, Armenia P. Boonpornprasert, Y. Chen, J.D. Good, M. Krasilnikov, O. Lishilin, G. Loisch, S. Philipp, H.J. Qian, Y. Renier, F. Stephan DESY Zeuthen, Zeuthen, Germany P. Piot Fermilab, Batavia, Illinois, USA P. Piot Northern Illinois University, DeKalb, Illinois, USA
	We report on the experimental demonstration of ballistic bunching of photoinjected, nC-scale electron bunches at the PITZ facility. In the experiment, electron bunches emanating from the photocathode were directly focused into a mm-scale dielectric-lined waveguide. The wakefield excited by the bunch acts back onto itself, leading to an energy modulation, which at a relatively low energy of 6~MeV, is converted into a density modulation before entering the linac ∼ 1~m downstream. We discuss the basic theory, experimental layout and results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB122
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THPAB017	Investigation of High Repetition Rate Femtosecond Electron Diffraction at PITZ	3727
	H.J. Qian, M. Groß, M. Krasilnikov, A. Oppelt, F. Stephan DESY Zeuthen, Zeuthen, Germany
	PITZ is a photoinjector test facility for FLASH and European XFEL, and it has been proposed to be a prototype machine to develop an accelerator based THz/IR source for European XFEL pump-probe experiment. In addition, the machine can also support femtosecond electron diffraction at the same beam repetition rate as European XFEL, which brings XFEL users more flexibility for different experiments. In this paper, a femtosecond electron diffraction scheme based on the PITZ accelerator setup is investigated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB017
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THPIK120	The RF and Mechanical Design of a Compact, 2.5 kW, 1.3 GHz Resonant Loop Coupler for the APEX Buncher Cavity	4380
	S.P. Virostek, F. Sannibale, J.W. Staples LBNL, Berkeley, California, USA H.J. Qian DESY Zeuthen, Zeuthen, Germany
	Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231. The Advanced Photo-injector Experiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is an injector system designed to demonstrate the capability of a normal conducting 186 MHz RF gun operating in CW mode to deliver the brightness required by X-ray FEL applications operating at MHz repetition rate, such as LCLS-II. A 240 kV, 1.3 GHz CW buncher cavity design was developed as part of the APEX experiment. The two-cell cavity profile has been optimized to minimize the RF power requirements and to remove multipacting resonances over the full range of operation. In order to excite the cavity stably at pi-mode and remove the dipole-like coupler kick, the two cells are to be independently driven by four, 2.5 kW, coaxial resonant loop couplers with integrated ceramic windows and a matching section in the body of the coupler. The coupler's inner conductor has a single diameter change at a specified distance from the ceramic insulator in order to cancel the wave reflected from the ceramic window, thus comprising the matching section. The details of the RF analysis, mechanical design, fabrication and testing of the coupler are presented here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK120
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Paper

Title

Page

Statistics on High Average Power Operation and Results from the Electron Beam Characterization at PITZ

1806

Y. Renier, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, T. Rublack, C. Saisa-ard, F. Stephan, Q.T. Zhao
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
M. Bousonville, S. Choroba, S. Lederer
DESY, Hamburg, Germany

The Photo Injector Test Facility at DESY in Zeuthen (PITZ) develops, tests and characterizes high brightness electron sources for FLASH and European XFEL. Since these FELs work with superconducting accelerators in pulsed mode, also the corresponding normal-conducting RF gun has to operate with long RF pulses. Generating high beam quality from the photo-cathode RF gun in addition requires a high accelerating gradient at the cathode. Therefore, the RF gun has to ensure stable and reliable operation at high average RF power, e.g. 6.5 MW peak power in the gun for 650 μs RF pulse length and 10 Hz repetition rate for the European XFEL. Several RF gun setups have been operated towards these goals over the last years. The latest gun setup is in operation since March 2016 and includes RF Gun 4.6 with an improved contact spring design. The RF input distribution consists of a coaxial coupler, a T-combiner and 2 RF windows from DESY production. In this contribution we will present statistics on the high average power operation and results from the characterization of the produced electron beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK051

Export •

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

WEPAB033

Experimental Optimization and Characterization of Electron Beams for Generating IR/THz SASE FEL Radiation with PITZ

2650

P. Boonpornprasert, Y. Chen, J.D. Good, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, T. Rublack, F. Stephan
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
C. Saisa-ard
Chiang Mai University, Chiang Mai, Thailand
Q.T. Zhao
IMP/CAS, Lanzhou, People's Republic of China

The Photo Injector Test facility at DESY, Zeuthen site (PITZ), develops high brightness electron sources for modern linac-based Free Electron Lasers (FELs). The PITZ accelerator can also be considered as a suitable machine for the development of an IR/THz source prototype for pump-probe experiments at the European XFEL. One of the interesting options for the IR/THz generation with PITZ is to generate the radiation by means of a SASE FEL using an uncompressed electron beam with bunch length of a few 10 ps and a peak current of ~200 A. In this paper, results of experimental optimizations and characterizations, including transverse phase space, slice transverse emittance and longitudinal phase space, of electron beams with bunch charges of 4 nC are presented and discussed. The measurements were done with beam momenta of 15 MeV/c and 22 MeV/c. Results of IR/THz SASE FEL calculations by using the GENESIS1.3 code based on the measured beam parameters are also presented and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB033

Export •

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

WEPAB122

Experimental Demonstration of Ballistic Bunching with Dielectric-Lined Waveguides at Pitz

2857

F. Lemery
University of Hamburg, Hamburg, Germany
G.A. Amatuni, B. Grigoryan
CANDLE, Yerevan, Armenia
P. Boonpornprasert, Y. Chen, J.D. Good, M. Krasilnikov, O. Lishilin, G. Loisch, S. Philipp, H.J. Qian, Y. Renier, F. Stephan
DESY Zeuthen, Zeuthen, Germany
P. Piot
Fermilab, Batavia, Illinois, USA
P. Piot
Northern Illinois University, DeKalb, Illinois, USA

We report on the experimental demonstration of ballistic bunching of photoinjected, nC-scale electron bunches at the PITZ facility. In the experiment, electron bunches emanating from the photocathode were directly focused into a mm-scale dielectric-lined waveguide. The wakefield excited by the bunch acts back onto itself, leading to an energy modulation, which at a relatively low energy of 6~MeV, is converted into a density modulation before entering the linac ∼ 1~m downstream. We discuss the basic theory, experimental layout and results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB122

Export •

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

THPAB017

Investigation of High Repetition Rate Femtosecond Electron Diffraction at PITZ

3727

H.J. Qian, M. Groß, M. Krasilnikov, A. Oppelt, F. Stephan
DESY Zeuthen, Zeuthen, Germany

PITZ is a photoinjector test facility for FLASH and European XFEL, and it has been proposed to be a prototype machine to develop an accelerator based THz/IR source for European XFEL pump-probe experiment. In addition, the machine can also support femtosecond electron diffraction at the same beam repetition rate as European XFEL, which brings XFEL users more flexibility for different experiments. In this paper, a femtosecond electron diffraction scheme based on the PITZ accelerator setup is investigated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB017

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

THPIK120

The RF and Mechanical Design of a Compact, 2.5 kW, 1.3 GHz Resonant Loop Coupler for the APEX Buncher Cavity

4380

S.P. Virostek, F. Sannibale, J.W. Staples
LBNL, Berkeley, California, USA
H.J. Qian
DESY Zeuthen, Zeuthen, Germany

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The Advanced Photo-injector Experiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is an injector system designed to demonstrate the capability of a normal conducting 186 MHz RF gun operating in CW mode to deliver the brightness required by X-ray FEL applications operating at MHz repetition rate, such as LCLS-II. A 240 kV, 1.3 GHz CW buncher cavity design was developed as part of the APEX experiment. The two-cell cavity profile has been optimized to minimize the RF power requirements and to remove multipacting resonances over the full range of operation. In order to excite the cavity stably at pi-mode and remove the dipole-like coupler kick, the two cells are to be independently driven by four, 2.5 kW, coaxial resonant loop couplers with integrated ceramic windows and a matching section in the body of the coupler. The coupler's inner conductor has a single diameter change at a specified distance from the ceramic insulator in order to cancel the wave reflected from the ceramic window, thus comprising the matching section. The details of the RF analysis, mechanical design, fabrication and testing of the coupler are presented here.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK120

Export •

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