IPAC2018 - List of Authors (Lederer, S.)

Paper	Title	Page
TUPMF086	Status of the ARES RF Gun at SINBAD: From its Characterization and Installation towards Commissioning	1474
	B. Marchetti, R.W. Aßmann, S. Baark, F. Burkart, U. Dorda, K. Flöttmann, I. Hartl, J. Hauser, J. Herrmann, M. Hüning, K. Knebel, O. Krebs, G. Kube, W. Kuropka, S. Lederer, F. Lemery, F. Ludwig, D. Marx, F. Mayet, M. Pelzer, I. Peperkorn, F. Poblotzki, S. Pumpe, J. Rothenburg, H. Schlarb, M. Titberidze, G. Vashchenko, T. Vinatier, P.A. Walker, L. Winkelmann, K. Wittenburg, S. Yamin, J. Zhu DESY, Hamburg, Germany
	The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) is foreseen to host multiple experiments relating to the production of ultra-short electron bunches and novel high gradient acceleration techniques. The SINBAD-ARES linac will be a conventional S-band linear RF accelerator allowing the production of low charge (0.5 pC - tens pC) ultra-short electron bunches (FWHM length =< 1 fs - few fs) with 100 MeV energy. The installation of the linac will proceed in stages. In this paper we report on the status of the characterization of the ARES RF gun and the installations of the related infrastructure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF086
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WEPMF055	The REGAE Accelerator Vacuum System	2493
	S. Lederer, K. Flöttmann, L. Lilje, N. Plambeck DESY, Hamburg, Germany
	Since 2011 the Relativistic Electron Gun for Atomic Exploration (REGAE) is operated at DESY in Hamburg. The accelerator consists mainly of a high gradient S-band RF-gun, which generates ultra-low emittance electron bunches, and an S-band RF-buncher cavity for bunch compression. In this contribution we describe the vacuum system of the REGAE accelerator. We will cover design aspects, applied cleaning and installation procedures as well as operation experience over the last years.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF055
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WEPMF056	Cs2Te Photocathode Lifetime at Flash and European XFEL	2496
	S. Lederer, S. Schreiber DESY, Hamburg, Germany
	The photo-injectors of FLASH and the European XFEL at DESY (Hamburg, Germany) use Cs2Te photocathodes. In this contribution we give an update on the lifetime and quantum efficiency of the cathodes operated in both facilities. Cathode #680.1 was operated at the European XFEL from the injector commissioning to the first user run for over 700 days. At FLASH cathode #73.3 has been operated with a record of more than 1000 days.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF056
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THPAL068	Status of the Polarix-TDS Project	3808
	P. Craievich, M. Bopp, H.-H. Braun, R. Ganter, T. Kleeb, M. Pedrozzi, E. Prat, S. Reiche, R. Zennaro PSI, Villigen PSI, Switzerland R.W. Aßmann, F. Christie, R.T.P. D'Arcy, U. Dorda, M. Foese, P. González Caminal, M. Hoffmann, M. Hüning, R. Jonas, O. Krebs, S. Lederer, V. Libov, B. Marchetti, D. Marx, J. Osterhoff, F. Poblotzki, M. Reukauff, H. Schlarb, S. Schreiber, G. Tews, M. Vogt, A. Wagner DESY, Hamburg, Germany N. Catalán Lasheras, A. Grudiev, G. McMonagle, W. Wuensch CERN, Geneva, Switzerland
	A collaboration between DESY, PSI and CERN has been established to develop and build an advanced modular X-band transverse deflection structure (TDS) system with the new feature of providing variable polarization of the deflecting force. This innovative CERN design requires very high manufacturing precision to guarantee highest azimuthal symmetry of the structure to avoid the deterioration of the polarization of the streaking field. Therefore, the high-precision tuning-free production process developed at PSI for the C-band and X-band accelerating structures will be used for the manufacturing. We summarize in this paper the status of the production of the prototype and the waveguide networks foreseen in the different facilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL068
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THPAL095	Metal Photocathodes Preparation for Compact Linear Accelerator at Daresbury Laboratory	3865
	A.N. Hannah, J.A. Conlon, L.B. Jones, B.L. Militsyn, T.C.Q. Noakes, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom V. R. Dhanak The University of Liverpool, Liverpool, United Kingdom L.B. Jones, B.L. Militsyn Cockcroft Institute, Warrington, Cheshire, United Kingdom S. Lederer DESY Zeuthen, Zeuthen, Germany S. Lederer DESY, Hamburg, Germany
	The photoinjector of the CLARA FEL test facility Front End at Daresbury Laboratory is based on a S-band 10 Hz photocathode RF-gun operating with a copper photocath-ode which is driven by the third harmonic of a Ti:Sapphire laser (266 nm). The main aim of this study was to establish a procedure to prepare the Cu surface prior to installation so a Quantum Efficiency (QE) of 10^-5 or higher can be achieved at laser power density below the ablation threshold of copper. The best results have been obtained by ex-situ chemical cleaning. This removed the surface oxide layer whilst at the same time producing a surface buffer layer. This inhibited the regrowth of native oxide for up to a week when exposed to normal ambient atmospheric conditions. With either chemical cleaning or Ar plasma cleaning after heating the sample in-situ to 150 °C for 90 minutes or 250 °C for 40 hours, almost all of the surface oxide was removed. For these surfaces a QE of 4.10-5 or better was measured. Oxygen plasma cleaning at 100% and 20% power produced CuO layer with surface carbon contaminant to 3 atomic %, however in-situ thermal cycling resulted in at best a QE of 3·10-6.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL095
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Paper

Title

Page

Status of the ARES RF Gun at SINBAD: From its Characterization and Installation towards Commissioning

1474

B. Marchetti, R.W. Aßmann, S. Baark, F. Burkart, U. Dorda, K. Flöttmann, I. Hartl, J. Hauser, J. Herrmann, M. Hüning, K. Knebel, O. Krebs, G. Kube, W. Kuropka, S. Lederer, F. Lemery, F. Ludwig, D. Marx, F. Mayet, M. Pelzer, I. Peperkorn, F. Poblotzki, S. Pumpe, J. Rothenburg, H. Schlarb, M. Titberidze, G. Vashchenko, T. Vinatier, P.A. Walker, L. Winkelmann, K. Wittenburg, S. Yamin, J. Zhu
DESY, Hamburg, Germany

The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) is foreseen to host multiple experiments relating to the production of ultra-short electron bunches and novel high gradient acceleration techniques. The SINBAD-ARES linac will be a conventional S-band linear RF accelerator allowing the production of low charge (0.5 pC - tens pC) ultra-short electron bunches (FWHM length =< 1 fs - few fs) with 100 MeV energy. The installation of the linac will proceed in stages. In this paper we report on the status of the characterization of the ARES RF gun and the installations of the related infrastructure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF086

Export •

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

WEPMF055

The REGAE Accelerator Vacuum System

2493

S. Lederer, K. Flöttmann, L. Lilje, N. Plambeck
DESY, Hamburg, Germany

Since 2011 the Relativistic Electron Gun for Atomic Exploration (REGAE) is operated at DESY in Hamburg. The accelerator consists mainly of a high gradient S-band RF-gun, which generates ultra-low emittance electron bunches, and an S-band RF-buncher cavity for bunch compression. In this contribution we describe the vacuum system of the REGAE accelerator. We will cover design aspects, applied cleaning and installation procedures as well as operation experience over the last years.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF055

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

WEPMF056

Cs2Te Photocathode Lifetime at Flash and European XFEL

2496

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

The photo-injectors of FLASH and the European XFEL at DESY (Hamburg, Germany) use Cs2Te photocathodes. In this contribution we give an update on the lifetime and quantum efficiency of the cathodes operated in both facilities. Cathode #680.1 was operated at the European XFEL from the injector commissioning to the first user run for over 700 days. At FLASH cathode #73.3 has been operated with a record of more than 1000 days.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF056

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THPAL068

Status of the Polarix-TDS Project

3808

P. Craievich, M. Bopp, H.-H. Braun, R. Ganter, T. Kleeb, M. Pedrozzi, E. Prat, S. Reiche, R. Zennaro
PSI, Villigen PSI, Switzerland
R.W. Aßmann, F. Christie, R.T.P. D'Arcy, U. Dorda, M. Foese, P. González Caminal, M. Hoffmann, M. Hüning, R. Jonas, O. Krebs, S. Lederer, V. Libov, B. Marchetti, D. Marx, J. Osterhoff, F. Poblotzki, M. Reukauff, H. Schlarb, S. Schreiber, G. Tews, M. Vogt, A. Wagner
DESY, Hamburg, Germany
N. Catalán Lasheras, A. Grudiev, G. McMonagle, W. Wuensch
CERN, Geneva, Switzerland

A collaboration between DESY, PSI and CERN has been established to develop and build an advanced modular X-band transverse deflection structure (TDS) system with the new feature of providing variable polarization of the deflecting force. This innovative CERN design requires very high manufacturing precision to guarantee highest azimuthal symmetry of the structure to avoid the deterioration of the polarization of the streaking field. Therefore, the high-precision tuning-free production process developed at PSI for the C-band and X-band accelerating structures will be used for the manufacturing. We summarize in this paper the status of the production of the prototype and the waveguide networks foreseen in the different facilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL068

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THPAL095

Metal Photocathodes Preparation for Compact Linear Accelerator at Daresbury Laboratory

3865

A.N. Hannah, J.A. Conlon, L.B. Jones, B.L. Militsyn, T.C.Q. Noakes, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
V. R. Dhanak
The University of Liverpool, Liverpool, United Kingdom
L.B. Jones, B.L. Militsyn
Cockcroft Institute, Warrington, Cheshire, United Kingdom
S. Lederer
DESY Zeuthen, Zeuthen, Germany
S. Lederer
DESY, Hamburg, Germany

The photoinjector of the CLARA FEL test facility Front End at Daresbury Laboratory is based on a S-band 10 Hz photocathode RF-gun operating with a copper photocath-ode which is driven by the third harmonic of a Ti:Sapphire laser (266 nm). The main aim of this study was to establish a procedure to prepare the Cu surface prior to installation so a Quantum Efficiency (QE) of 10^-5 or higher can be achieved at laser power density below the ablation threshold of copper. The best results have been obtained by ex-situ chemical cleaning. This removed the surface oxide layer whilst at the same time producing a surface buffer layer. This inhibited the regrowth of native oxide for up to a week when exposed to normal ambient atmospheric conditions. With either chemical cleaning or Ar plasma cleaning after heating the sample in-situ to 150 °C for 90 minutes or 250 °C for 40 hours, almost all of the surface oxide was removed. For these surfaces a QE of 4.10-5 or better was measured. Oxygen plasma cleaning at 100% and 20% power produced CuO layer with surface carbon contaminant to 3 atomic %, however in-situ thermal cycling resulted in at best a QE of 3·10-6.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL095

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