FEL2015 - List of Keywords (cathode)

Paper	Title	Other Keywords	Page
MOP021	LCLS-II Injector Beamline Design and RF Coupler Correction	emittance, cavity, solenoid, quadrupole	77
	F. Zhou, D. Dowell, R.K. Li, T.O. Raubenheimer, J.F. Schmerge SLAC, Menlo Park, California, USA C.E. Mitchell, C. F. Papadopoulos, F. Sannibale LBNL, Berkeley, California, USA A. Vivoli Fermilab, Batavia, Illinois, USA
	Funding: U.S. DOE contract #DE-AC02-76SF00515. LCLS-II CW injector beamline consists of a 186 MHz normal conducting (NC) RF gun for beam generation and acceleration to 750 keV, two solenoids for the beam focusing, two BPMs, 1.3 GHz NC RF buncher for bunch compression down to 3-4 ps rms, 1.3 GHz superconducting standard 8-cavity cryomodule to boost beam energy to about 98 MeV. The beamline is being optimized to accommodate all essential components and maximize beam quality. The beamline layouts and beam dynamics are presented and compared. The 3D RF field perturbation due to cavity couplers where the beam energy is very low (<1 MeV) causes significant emittance growth especially for a large-size beam. A theory of rotated fields predicted and simulations verified using a weak skew quadrupole located even a significant distance from the perturbation can completely eliminate the emittance growth. A layout for future upgrade is developed. The results are presented and analysed.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOP024	Status, Plans and Recent Results from the APEX Project at LBNL	gun, linac, cavity, electron	81
	F. Sannibale, K.M. Baptiste, C.W. Cork, S. De Santis, M.R. Dickinson, L.R. Doolittle, J.A. Doyle, J. Feng, D. Filippetto, G.L. Harris, G. Huang, R. Huang, M.J. Johnson, M.S. Jones, T.D. Kramasz, S. Kwiatkowski, D. Leitner, R.E. Lellinger, C.E. Mitchell, V. Moroz, W.E. Norum, H.A. Padmore, G.J. Portmann, H.J. Qian, J.W. Staples, D. L. Syversrud, M. Vinco, S.P. Virostek, R.P. Wells, M.S. Zolotorev LBNL, Berkeley, California, USA R. Huang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 The Advanced Photo-injector EXperiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is dedicated to the demonstration of the capability of an electron injector based on the VHF-gun, the new concept RF gun developed at LBNL, of delivering the beam quality required by MHz-class repetition rate X-Ray free electron lasers. Project status, plans, and recent results are presented.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOD01	Review of Experimental Results from High Brightness DC Guns: Highlights in FEL Applications	gun, emittance, FEL, brightness	269
	N. Nishimori JAEA, Ibaraki-ken, Japan
	Funding: This work is partially supported by a JSPS Grant-in-Aid for Scientific Research in Japan (15H03594). Future ERL light sources and high repetition rate X-ray FELs require high-brightness and high-current electron guns. A DC photoemission gun is one of the most promising candidates for such guns, because a record high current of 65 mA and generation of high brightness beam with 90% normalized emittances of 0.3 mm-mrad with bunch charge of 77 pC were recently demonstrated at the Cornell photoinjector with a 350 kV photoemission gun [1,2]. Further increase of the gun high voltage is desirable to reduce space charge induced emittance growth especially for high bunch charge application such as X-ray FEL. Employment of a segmented insulator is a key to reach higher voltage [3]. This technique led to generation of 500 keV beam from the JAEA gun with 160mm acceleration gap [4], conditioning voltage more than 500 kV at the Cornell gun with gap < 50 mm [5], and demonstration of 500 kV holding for 10 hours at the KEK gun with 70 mm gap [6]. In this talk, we present recent experimental results of high brightness DC guns and discuss highlights and limitations in FEL applications. [1] Dunham, APL 102, 034105. [2] Gulliford, PRSTAB 16, 073401. [3] Nagai, RSI 81, 033304. [4] Nishimori, APL 102, 234103. [5] Maxson, RSI 85, 093306. [6] Yamamoto, private communication.
	Slides MOD01 [3.051 MB]
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOD03	Alkali Cathode Testing for LCLS-II at APEX	gun, electron, operation, laser	280
	H.J. Qian, J. Feng, D. Filippetto, J.R. Nasiatka, H.A. Padmore, F. Sannibale LBNL, Berkeley, California, USA R.K. Li, J.F. Schmerge, F. Zhou SLAC, Menlo Park, California, USA
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 Electron sources of high brightness and high bunch charge (~300 pC) with MHz repetition rate are one of the key technologies for next generation X-FEL facilities such as the LCLS-II at SLAC and the Euro XFEL at DESY. The Advanced Photoinjector EXperiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is developing such an electron source based on high quantum efficiency (QE) alkali photocathodes and the VHF-Gun, a new scheme normal conducting RF gun developed at LBNL. The VHF-Gun already demonstrated stable CW operation with high gradient (~ 20 MV/m), high gun voltage (~ 750 kV) and low vacuum pressure (~ 3 E-10 torr) laying the foundation for the generation of high brightness electron beams. In this paper, we report the test and characterization of several different alkali cathodes in high average current (several hundreds of pC/bunch with MHz repetition rate) operation at APEX. Measurements include cathode life time, QE map evolution and thermal emittance characterization, to investigate the compatibility of such cathodes with the challenging requirements of LCLS-II.
	Slides MOD03 [6.030 MB]
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP034	New Ellipsoidal Photocathode Laser Pulses at the Upgraded PITZ Facility	gun, laser, simulation, electron	439
	J.D. Good, P. Boonpornprasert, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, G. Kourkafas, M. Krasilnikov, D. Melkumyan, A. Oppelt, M. Otevřel, Y. Renier, T. Rublack, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany A.V. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky IAP/RAS, Nizhny Novgorod, Russia G. Asova INRNE, Sofia, Bulgaria M. A. Bakr Assiut University, Assiut, Egypt I. Hartl, S. Schreiber DESY, Hamburg, Germany C. Hernandez-Garcia JLab, Newport News, Virginia, USA M. Khojoyan SOLEIL, Gif-sur-Yvette, France O. Lishilin, G. Pathak Uni HH, Hamburg, Germany D. Malyutin HZB, Berlin, Germany E. Syresin JINR, Dubna, Moscow Region, Russia Q.T. Zhao IMP/CAS, Lanzhou, People's Republic of China
	High brightness electron sources for free electron lasers like FLASH and the European XFEL are developed, optimized and characterized at the Photo Injector Test facility at DESY in Zeuthen (PITZ). Last year the facility was significantly upgraded with a new prototype photocathode laser capable of producing homogeneous ellipsoidal pulses. Previous simulations have shown that the corresponding pulses produce high brightness electron bunches with minimized emittance. Furthermore, a new normal conducting RF gun cavity was installed with a modified two-window waveguide RF feed layout for stability and reliability tests, as required for the European XFEL. Other relevant additions to the facility include beamline modifications for improved electron beam transport through the PITZ accelerator, refinement of both the cooling and RF systems for improved parameter stability, and preparations for the installation of a plasma cell. This paper describes the facility upgrades and reports on the operational experience with the new components.
	Poster TUP034 [1.211 MB]
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP035	Operation of a Slit Emittance Meter in the MAX IV Gun Test Stand	emittance, gun, laser, background	444
	J. Andersson, F. Curbis, M. Isinger, F. Lindau, S. Werin MAX-lab, Lund, Sweden
	The MAX IV facility in Lund, Sweden is currently under commissioning. There are two guns in the current MAX IV injector, one thermionic gun for storage ring injection and one photocathode gun for the Short Pulse Facility. There is a possibility of extending the facility to include a Free Electron Laser. To investigate how the beam from the injector can be improved and how to match it to the future requirements for a FEL, the emittance meter from SPARC has been recommissioned at the MAX IV gun test stand. In this paper we report on the progress of this work and results from the first measurements.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP036	Initial Commissioning Results of the MAX IV Injector	gun, linac, laser, emittance	448
	J. Andersson, F. Curbis, M. Eriksson, D. Kumbaro, F. Lindau, E. Mansten, D.F. Olsson, S. Thorin, S. Werin MAX-lab, Lund, Sweden
	The MAX IV facility in Lund, Sweden is currently under commissioning. In the MAX IV injector there are two guns, one thermionic gun for storage ring injection and one photocathode gun for the Short Pulse Facility. The commissioning of the injector and the LINAC has been ongoing for the last year and ring commissioning is due to start shortly. In this paper we will present the results from beam performance experiments for the injector at the current stage of commissioning.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP041	Simultaneous Operation of Three Laser Systems at the FLASH Photoinjector	laser, electron, operation, free-electron-laser	459
	S. Schreiber, C. Grün, K. Klose, J. Rönsch-Schulenburg, B. Steffen DESY, Hamburg, Germany
	The free-electron laser facility FLASH at DESY (Hamburg, Germany) operates two undulator beamlines simultaneously. Both undulator beamlines are driven by a common linear superconducting accelerator with a beam energy of up to 1.25 GeV. The superconducting technology allows the acceleration of trains of several hundred microsecond spaced bunches with a repetition rate of 10 Hz. A fast kickers-septum system is installed to distribute one part of the electron bunch train to FLASH1 and the other part to FLASH2 keeping the full 10 Hz repetition rate for both beamlines. In order to deliver different beam properties to each beamline, the FLASH photoinjector uses two independent laser systems to generate different bunch pattern and bunch charges. One laser serves the FLASH1 beamline, the other the FLASH2 beamline. A third laser with adjus ö laser pulse duration is used to generate ultra-short bunches for single spike lasing.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP042	Lifetime of Cs2Te Cathodes Operated at the FLASH Facility	laser, gun, operation, electron	464
	S. Schreiber, S. Lederer DESY, Hamburg, Germany
	The injector of the free-electron laser facility FLASH at DESY (Hamburg, Germany) uses Cs2Te photocathodes. We report on the lifetime, quantum efficiency (QE), and darkcurrent of photocathodes operated at FLASH during the last year. Cathode 618.3 has been operated for a record of 439 days with a stable QE in the order of 3%. The fresh cathode 73.3 shows an enhancement of emitted electrons for a few microseconds of a 1 MHz pulse train.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP065	Beam Dynamics Simulation for the Upgraded PITZ Photo Injector Applying Various Photocathode Laser Pulses	emittance, laser, electron, flattop	501
	M. A. Bakr, M. Khojoyan, M. Krasilnikov, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany M. A. Bakr Assiut University, Assiut, Egypt
	The Photo Injector Test facility PITZ at DESY, Zeuthen site, characterizes and optimizes high brightness electron sources for linac-based Free Electron Laser (FELs) with a specific focus on the requirements of FLASH and the European XFEL. X-ray FELs require high brightness electron beam in terms of high peak current, small transverse emittance and energy spread. Such high quality beams are mandatory for efficient SASE generation in a single pass through long undulators with narrow gaps. Photocathode laser pulse shaping is a powerful tool to optimize the photo injector performance. Recently, a new photocathode laser system capable of producing 3D quasi-ellipsoidal pulses has been installed at PITZ. It is foreseen to operate this new system in parallel to the nominal one that generates cylindrical pulses with various temporal profiles. A set of numerical simulations was performed to study and compare the beam dynamics of electron beams produced with 3D ellipsoidal laser profile with the typical cylindrically shaped (flat-top) profile. Different bunch charges from 20 pC up to several nC are considered, in order to find an optimum PITZ machine setup which will yield the lowest transverse emittance. we present and discuss the results of this comparison in the submission.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP072	Cathode Ion Bombardment in LCLS and LCLS-II RF Gun	ion, gun, cavity, solenoid	534
	L. Wang, A. Brachmann, F.-J. Decker, Z. Li, T.O. Raubenheimer, J.F. Schmerge, F. Zhou SLAC, Menlo Park, California, USA
	This paper studies the ions bombardment on the cathode in the LCLS and LCLS-II gun. APEX gun is used here for LCLS-II, which will be operate at 1 MHz repetition rate. Therefore, It is important to estimate the ion bombardment. One specific PIC code is used track arbitrary particles (ions and electron here) in arbitrary 2D/3D electromagnetic field and solenoid field to estimate the possibility of ion bombardment. The LCLS gun has 1.6 cells while the LCLS-II gun (APEX gun) is a half-cell gun. The frequencies of the two guns are also quite different. These characters make the ion dynamics quite differently. We estimated the bombardment for various ion species and studied the effects RF pulse shape and RF phase
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUD03	First Results of the SRF Gun Test for CeC PoP Experiment	gun, laser, electron, cavity	564
	I. Pinayev, Z. Altinbas, S.A. Belomestnykh, K.A. Brown, J.C. Brutus, A.J. Curcio, A. Di Lieto, C. Folz, D.M. Gassner, M. Harvey, J.P. Jamilkowski, Y.C. Jing, D. Kayran, R. Kellermann, R.F. Lambiase, V. Litvinenko, G.J. Mahler, M. Mapes, W. Meng, T.A. Miller, M.G. Minty, G. Narayan, P. Orfin, T. Rao, J. Reich, B. Sheehy, J. Skaritka, L. Smart, K.S. Smith, L. Snydstrup, V. Soria, R. Than, C. Theisen, J.E. Tuozzolo, E. Wang, G. Wang, B. P. Xiao, T. Xin, W. Xu, A. Zaltsman BNL, Upton, Long Island, New York, USA
	We have started the first tests of the equipment for the coherent electron cooling proof-of-principle experiment. After tests of the 500 MHz normal conducting cavities we proceeded with the low power beam tests of a CW SRF gun. The results of the tests with record beam parameters are presented.
	Slides TUD03 [1.201 MB]
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

WEP003	Recent Understanding and Improvements of the LCLS Injector	laser, emittance, FEL, electron	592
	F. Zhou, D.K. Bohler, Y. Ding, S. Gilevich, Z. Huang, H. Loos, D.F. Ratner SLAC, Menlo Park, California, USA
	Funding: U.S. DOE contract No. DE-AC02-76SF00515. Ultraviolet drive laser and copper photocathode are the key systems for reliably delivering <0.4 micron of emittance and high brightness free electron laser (FEL) at the linac coherent light source (LCLS). Characterizing, optimizing and controlling laser distributions in both spatial and temporal directions are important for ultra-low emittance generation. Spatial truncated Gaussian laser profile has been demonstrated to produce better emittance than a spatial uniform beam. Sensitivity of the spatial laser distribution for the emittance is measured and analysed. Stacking two 2-ps Gaussian laser beams significantly improves emittance and eventually FEL performance at the LCLS in comparison to a single 2-ps Gaussian laser pulse. In addition, recent observations at the LCLS show that the micro-bunching effect depends strongly on the cathode spot locations. The dependence of the micro-bunching and FEL performance on the cathode spot location is mapped and discussed.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOP021

LCLS-II Injector Beamline Design and RF Coupler Correction

emittance, cavity, solenoid, quadrupole

77

F. Zhou, D. Dowell, R.K. Li, T.O. Raubenheimer, J.F. Schmerge
SLAC, Menlo Park, California, USA
C.E. Mitchell, C. F. Papadopoulos, F. Sannibale
LBNL, Berkeley, California, USA
A. Vivoli
Fermilab, Batavia, Illinois, USA

Funding: U.S. DOE contract #DE-AC02-76SF00515.
LCLS-II CW injector beamline consists of a 186 MHz normal conducting (NC) RF gun for beam generation and acceleration to 750 keV, two solenoids for the beam focusing, two BPMs, 1.3 GHz NC RF buncher for bunch compression down to 3-4 ps rms, 1.3 GHz superconducting standard 8-cavity cryomodule to boost beam energy to about 98 MeV. The beamline is being optimized to accommodate all essential components and maximize beam quality. The beamline layouts and beam dynamics are presented and compared. The 3D RF field perturbation due to cavity couplers where the beam energy is very low (<1 MeV) causes significant emittance growth especially for a large-size beam. A theory of rotated fields predicted and simulations verified using a weak skew quadrupole located even a significant distance from the perturbation can completely eliminate the emittance growth. A layout for future upgrade is developed. The results are presented and analysed.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOP024

Status, Plans and Recent Results from the APEX Project at LBNL

gun, linac, cavity, electron

81

F. Sannibale, K.M. Baptiste, C.W. Cork, S. De Santis, M.R. Dickinson, L.R. Doolittle, J.A. Doyle, J. Feng, D. Filippetto, G.L. Harris, G. Huang, R. Huang, M.J. Johnson, M.S. Jones, T.D. Kramasz, S. Kwiatkowski, D. Leitner, R.E. Lellinger, C.E. Mitchell, V. Moroz, W.E. Norum, H.A. Padmore, G.J. Portmann, H.J. Qian, J.W. Staples, D. L. Syversrud, M. Vinco, S.P. Virostek, R.P. Wells, M.S. Zolotorev
LBNL, Berkeley, California, USA
R. Huang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
The Advanced Photo-injector EXperiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is dedicated to the demonstration of the capability of an electron injector based on the VHF-gun, the new concept RF gun developed at LBNL, of delivering the beam quality required by MHz-class repetition rate X-Ray free electron lasers. Project status, plans, and recent results are presented.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOD01

Review of Experimental Results from High Brightness DC Guns: Highlights in FEL Applications

gun, emittance, FEL, brightness

269

N. Nishimori
JAEA, Ibaraki-ken, Japan

Funding: This work is partially supported by a JSPS Grant-in-Aid for Scientific Research in Japan (15H03594).
Future ERL light sources and high repetition rate X-ray FELs require high-brightness and high-current electron guns. A DC photoemission gun is one of the most promising candidates for such guns, because a record high current of 65 mA and generation of high brightness beam with 90% normalized emittances of 0.3 mm-mrad with bunch charge of 77 pC were recently demonstrated at the Cornell photoinjector with a 350 kV photoemission gun [1,2]. Further increase of the gun high voltage is desirable to reduce space charge induced emittance growth especially for high bunch charge application such as X-ray FEL. Employment of a segmented insulator is a key to reach higher voltage [3]. This technique led to generation of 500 keV beam from the JAEA gun with 160mm acceleration gap [4], conditioning voltage more than 500 kV at the Cornell gun with gap < 50 mm [5], and demonstration of 500 kV holding for 10 hours at the KEK gun with 70 mm gap [6]. In this talk, we present recent experimental results of high brightness DC guns and discuss highlights and limitations in FEL applications.
[1] Dunham, APL 102, 034105.
[2] Gulliford, PRSTAB 16, 073401.
[3] Nagai, RSI 81, 033304.
[4] Nishimori, APL 102, 234103.
[5] Maxson, RSI 85, 093306.
[6] Yamamoto, private communication.

Slides MOD01 [3.051 MB]

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOD03

Alkali Cathode Testing for LCLS-II at APEX

gun, electron, operation, laser

280

H.J. Qian, J. Feng, D. Filippetto, J.R. Nasiatka, H.A. Padmore, F. Sannibale
LBNL, Berkeley, California, USA
R.K. Li, J.F. Schmerge, F. Zhou
SLAC, Menlo Park, California, USA

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
Electron sources of high brightness and high bunch charge (~300 pC) with MHz repetition rate are one of the key technologies for next generation X-FEL facilities such as the LCLS-II at SLAC and the Euro XFEL at DESY. The Advanced Photoinjector EXperiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is developing such an electron source based on high quantum efficiency (QE) alkali photocathodes and the VHF-Gun, a new scheme normal conducting RF gun developed at LBNL. The VHF-Gun already demonstrated stable CW operation with high gradient (~ 20 MV/m), high gun voltage (~ 750 kV) and low vacuum pressure (~ 3 E-10 torr) laying the foundation for the generation of high brightness electron beams. In this paper, we report the test and characterization of several different alkali cathodes in high average current (several hundreds of pC/bunch with MHz repetition rate) operation at APEX. Measurements include cathode life time, QE map evolution and thermal emittance characterization, to investigate the compatibility of such cathodes with the challenging requirements of LCLS-II.

Slides MOD03 [6.030 MB]

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP034

New Ellipsoidal Photocathode Laser Pulses at the Upgraded PITZ Facility

gun, laser, simulation, electron

439

J.D. Good, P. Boonpornprasert, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, G. Kourkafas, M. Krasilnikov, D. Melkumyan, A. Oppelt, M. Otevřel, Y. Renier, T. Rublack, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
A.V. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia
G. Asova
INRNE, Sofia, Bulgaria
M. A. Bakr
Assiut University, Assiut, Egypt
I. Hartl, S. Schreiber
DESY, Hamburg, Germany
C. Hernandez-Garcia
JLab, Newport News, Virginia, USA
M. Khojoyan
SOLEIL, Gif-sur-Yvette, France
O. Lishilin, G. Pathak
Uni HH, Hamburg, Germany
D. Malyutin
HZB, Berlin, Germany
E. Syresin
JINR, Dubna, Moscow Region, Russia
Q.T. Zhao
IMP/CAS, Lanzhou, People's Republic of China

High brightness electron sources for free electron lasers like FLASH and the European XFEL are developed, optimized and characterized at the Photo Injector Test facility at DESY in Zeuthen (PITZ). Last year the facility was significantly upgraded with a new prototype photocathode laser capable of producing homogeneous ellipsoidal pulses. Previous simulations have shown that the corresponding pulses produce high brightness electron bunches with minimized emittance. Furthermore, a new normal conducting RF gun cavity was installed with a modified two-window waveguide RF feed layout for stability and reliability tests, as required for the European XFEL. Other relevant additions to the facility include beamline modifications for improved electron beam transport through the PITZ accelerator, refinement of both the cooling and RF systems for improved parameter stability, and preparations for the installation of a plasma cell. This paper describes the facility upgrades and reports on the operational experience with the new components.

Poster TUP034 [1.211 MB]

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP035

Operation of a Slit Emittance Meter in the MAX IV Gun Test Stand

emittance, gun, laser, background

444

J. Andersson, F. Curbis, M. Isinger, F. Lindau, S. Werin
MAX-lab, Lund, Sweden

The MAX IV facility in Lund, Sweden is currently under commissioning. There are two guns in the current MAX IV injector, one thermionic gun for storage ring injection and one photocathode gun for the Short Pulse Facility. There is a possibility of extending the facility to include a Free Electron Laser. To investigate how the beam from the injector can be improved and how to match it to the future requirements for a FEL, the emittance meter from SPARC has been recommissioned at the MAX IV gun test stand. In this paper we report on the progress of this work and results from the first measurements.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP036

Initial Commissioning Results of the MAX IV Injector

gun, linac, laser, emittance

448

J. Andersson, F. Curbis, M. Eriksson, D. Kumbaro, F. Lindau, E. Mansten, D.F. Olsson, S. Thorin, S. Werin
MAX-lab, Lund, Sweden

The MAX IV facility in Lund, Sweden is currently under commissioning. In the MAX IV injector there are two guns, one thermionic gun for storage ring injection and one photocathode gun for the Short Pulse Facility. The commissioning of the injector and the LINAC has been ongoing for the last year and ring commissioning is due to start shortly. In this paper we will present the results from beam performance experiments for the injector at the current stage of commissioning.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP041

Simultaneous Operation of Three Laser Systems at the FLASH Photoinjector

laser, electron, operation, free-electron-laser

459

S. Schreiber, C. Grün, K. Klose, J. Rönsch-Schulenburg, B. Steffen
DESY, Hamburg, Germany

The free-electron laser facility FLASH at DESY (Hamburg, Germany) operates two undulator beamlines simultaneously. Both undulator beamlines are driven by a common linear superconducting accelerator with a beam energy of up to 1.25 GeV. The superconducting technology allows the acceleration of trains of several hundred microsecond spaced bunches with a repetition rate of 10 Hz. A fast kickers-septum system is installed to distribute one part of the electron bunch train to FLASH1 and the other part to FLASH2 keeping the full 10 Hz repetition rate for both beamlines. In order to deliver different beam properties to each beamline, the FLASH photoinjector uses two independent laser systems to generate different bunch pattern and bunch charges. One laser serves the FLASH1 beamline, the other the FLASH2 beamline. A third laser with adjus ö laser pulse duration is used to generate ultra-short bunches for single spike lasing.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP042

Lifetime of Cs2Te Cathodes Operated at the FLASH Facility

laser, gun, operation, electron

464

S. Schreiber, S. Lederer
DESY, Hamburg, Germany

The injector of the free-electron laser facility FLASH at DESY (Hamburg, Germany) uses Cs2Te photocathodes. We report on the lifetime, quantum efficiency (QE), and darkcurrent of photocathodes operated at FLASH during the last year. Cathode 618.3 has been operated for a record of 439 days with a stable QE in the order of 3%. The fresh cathode 73.3 shows an enhancement of emitted electrons for a few microseconds of a 1 MHz pulse train.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP065

Beam Dynamics Simulation for the Upgraded PITZ Photo Injector Applying Various Photocathode Laser Pulses

emittance, laser, electron, flattop

501

M. A. Bakr, M. Khojoyan, M. Krasilnikov, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
M. A. Bakr
Assiut University, Assiut, Egypt

The Photo Injector Test facility PITZ at DESY, Zeuthen site, characterizes and optimizes high brightness electron sources for linac-based Free Electron Laser (FELs) with a specific focus on the requirements of FLASH and the European XFEL. X-ray FELs require high brightness electron beam in terms of high peak current, small transverse emittance and energy spread. Such high quality beams are mandatory for efficient SASE generation in a single pass through long undulators with narrow gaps. Photocathode laser pulse shaping is a powerful tool to optimize the photo injector performance. Recently, a new photocathode laser system capable of producing 3D quasi-ellipsoidal pulses has been installed at PITZ. It is foreseen to operate this new system in parallel to the nominal one that generates cylindrical pulses with various temporal profiles. A set of numerical simulations was performed to study and compare the beam dynamics of electron beams produced with 3D ellipsoidal laser profile with the typical cylindrically shaped (flat-top) profile. Different bunch charges from 20 pC up to several nC are considered, in order to find an optimum PITZ machine setup which will yield the lowest transverse emittance. we present and discuss the results of this comparison in the submission.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP072

Cathode Ion Bombardment in LCLS and LCLS-II RF Gun

ion, gun, cavity, solenoid

534

L. Wang, A. Brachmann, F.-J. Decker, Z. Li, T.O. Raubenheimer, J.F. Schmerge, F. Zhou
SLAC, Menlo Park, California, USA

This paper studies the ions bombardment on the cathode in the LCLS and LCLS-II gun. APEX gun is used here for LCLS-II, which will be operate at 1 MHz repetition rate. Therefore, It is important to estimate the ion bombardment. One specific PIC code is used track arbitrary particles (ions and electron here) in arbitrary 2D/3D electromagnetic field and solenoid field to estimate the possibility of ion bombardment. The LCLS gun has 1.6 cells while the LCLS-II gun (APEX gun) is a half-cell gun. The frequencies of the two guns are also quite different. These characters make the ion dynamics quite differently. We estimated the bombardment for various ion species and studied the effects RF pulse shape and RF phase

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUD03

First Results of the SRF Gun Test for CeC PoP Experiment

gun, laser, electron, cavity

564

I. Pinayev, Z. Altinbas, S.A. Belomestnykh, K.A. Brown, J.C. Brutus, A.J. Curcio, A. Di Lieto, C. Folz, D.M. Gassner, M. Harvey, J.P. Jamilkowski, Y.C. Jing, D. Kayran, R. Kellermann, R.F. Lambiase, V. Litvinenko, G.J. Mahler, M. Mapes, W. Meng, T.A. Miller, M.G. Minty, G. Narayan, P. Orfin, T. Rao, J. Reich, B. Sheehy, J. Skaritka, L. Smart, K.S. Smith, L. Snydstrup, V. Soria, R. Than, C. Theisen, J.E. Tuozzolo, E. Wang, G. Wang, B. P. Xiao, T. Xin, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA

We have started the first tests of the equipment for the coherent electron cooling proof-of-principle experiment. After tests of the 500 MHz normal conducting cavities we proceeded with the low power beam tests of a CW SRF gun. The results of the tests with record beam parameters are presented.

Slides TUD03 [1.201 MB]

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

WEP003

Recent Understanding and Improvements of the LCLS Injector

laser, emittance, FEL, electron

592

F. Zhou, D.K. Bohler, Y. Ding, S. Gilevich, Z. Huang, H. Loos, D.F. Ratner
SLAC, Menlo Park, California, USA

Funding: U.S. DOE contract No. DE-AC02-76SF00515.
Ultraviolet drive laser and copper photocathode are the key systems for reliably delivering <0.4 micron of emittance and high brightness free electron laser (FEL) at the linac coherent light source (LCLS). Characterizing, optimizing and controlling laser distributions in both spatial and temporal directions are important for ultra-low emittance generation. Spatial truncated Gaussian laser profile has been demonstrated to produce better emittance than a spatial uniform beam. Sensitivity of the spatial laser distribution for the emittance is measured and analysed. Stacking two 2-ps Gaussian laser beams significantly improves emittance and eventually FEL performance at the LCLS in comparison to a single 2-ps Gaussian laser pulse. In addition, recent observations at the LCLS show that the micro-bunching effect depends strongly on the cathode spot locations. The dependence of the micro-bunching and FEL performance on the cathode spot location is mapped and discussed.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)