Session: THBxC - 02 Sep 2004
Gun/Injector Technology

THBOC02 Recent Results and Perspectives of the Low Emittance Photo Injector at PITZ
Frank Stephan, Juergen Baehr, Ulrich Gensch, Hans-Juergen Grabosch, Jang Hui Han, Mikhail Krasilnikov, Dirk Lipka, Velizar Miltchev, Anne Oppelt, Bagrat Petrosyan, Dietrich Pose, Sabine Riemann, Lazar Staykov (DESY Zeuthen, Zeuthen), Michael von Hartrott, Eberhardt Jaeschke, Dieter Krämer, Dieter Richter (BESSY GmbH, Berlin), Galina Asova, Gancho Dimitrov (DESY Zeuthen, Zeuthen; INRNE, Sofia), Karen Abrahamyan (DESY Zeuthen, Zeuthen; YerPhI, Yerevan), Ilja Bohnet, Jean-Paul Carneiro, Klaus Floettmann, Siegfried Schreiber (DESY, Hamburg), Paolo Michelato, Laura Monaco, Carlo Pagani, Daniele Sertore (INFN/LASA, Segrate (MI)), Ivan Tsakov (INRNE, Sofia), Wolfgang Sandner, Ingo Will (MBI, Berlin), Wolfgang Ackermann, Wolfgang F.O. Mueller, S. Schnepp, Stefan Setzer, Thomas Weiland (TU Darmstadt, Darmstadt), Joerg Rossbach (Uni HH, Hamburg)

The Photo Injector Test Facility at DESY Zeuthen (PITZ) was built to study the production of minimum transverse emittance electron beams for Free Electron Lasers. In November 2003 the electron beam from the RF gun was fully characterized at PITZ. For a bunch charge of 1 nC a minimum normalized projected beam emittance of 1.5 π mm mrad in the vertical plane and a minimum geometrical average of both transverse planes of 1.7 π mm mrad have been achieved. This fulfils the requirements of the VUV-FEL at DESY Hamburg. In this contribution an overview on the measured electron beam and high duty cycle RF parameters including transverse emittance, thermal emittance, bunch length, momentum and momentum spread will be given. In addition, planned major upgrades and first results towards fulfilling the even more challenging requirements for the European XFEL will be discussed. This includes the increase of the accelerating gradient on the photo-cathode and the improvement of the transverse and longitudinal laser beam parameters.

THBOC03 Emittance Measurement on the CeB6 Electron Gun for the SPring-8 Compact SASE Source
Kazuaki Togawa, Hitoshi Baba, Takahiro Inagaki, Kazuyuki Onoe, Tsumoru Shintake, Takashi Tanaka (RIKEN Spring-8 Harima, Hyogo), Hiroshi Matsumoto (KEK, Ibaraki)

A high-volatage pulsed electron gun has been constructed for the injector system of the soft X-ray FEL project at SPring-8 (SCSS project). A CeB6 single crystal was chosen as a thermionic cathode, because of its excellent emission properties. The gun voltage of -500 kV was chosen to reduce emittance growth due to space charge. We have succeeded in generating a 500 keV beam with 1 A peak current and 3 micro-sec FWHM. The beam was very stable with low jitter. The beam emittance has been measured by means of double-slits method, and the normalized rms emittance of 1.1 pi-mm-mrad has been obtained. We report on the experimental result on the emittance measurement of the CeB6 electron gun.

THBOC04 Ampere Average Current Photoinjector and Energy Recovery Linac
Ilan Ben-Zvi, A. Burrill, R. Calaga, P. Cameron, X. Chang, D. Gassner, H. Hahn, A. Hershcovitch, H.C. Hseuh, P. Johnson, D. Kayran, J. Kewisch, R. Lambiase, Vladimir N. Litvinenko, G. McIntyre, A. Nicoletti, J. Rank, T. Roser, J. Scaduto, K. Smith, T. Srinivasan-Rao, K.-C. Wu, A. Zaltsman, Y. Zhao (BNL, Upton, Long Island, New York), H. Bluem, A. Burger, Mike Cole, A. Favale, D. Holmes, John Rathke, Tom Schultheiss, A. Todd (AES, Medford, NY), J. Delayen, W. Funk, L. Phillips, Joe Preble (Jefferson Lab, Newport News, Virginia)

High-power Free-Electron Lasers were made possible by advances in superconducting linac operated in an energy-recovery mode, as demonstrated by the spectacular success of the Jefferson Laboratory IR-Demo. In order to get to much higher power levels, say a fraction of a megawatt average power, many technological barriers are yet to be broken. BNL’s Collider-Accelerator Department is pursuing some of these technologies for a different application, that of electron cooling of high-energy hadron beams. I will describe work on CW, high-current and high-brightness electron beams. This will include a description of a superconducting, laser-photocathode RF gun employing a new secondary-emission multiplying cathode and an accelerator cavity, both capable of producing of the order of one ampere average current.

THBOC05 Status of the 3 1/2 Cell Rossendorf Superconducting RF Gun
Dietmar Janssen, Hartmut Buettig, Pavel Evtushenko, Ulf Lehnert, Peter Michel, Christof Schneider, Juergen Stephan, Jochen Teichert (FZR, Dresden), Slava Kruchkov, Oleg Myskin, Vladimir Volkov (BINP, Novosibirsk)

In Rossendorf it was shown for the first time that a RF electron gun where a photo cathode is inside a superconducting cavity, works stable over a period of seven weeks. At 4.2K no change of the quality factor Q = 2.5 108 has been observed [1]. The experimental results were the basis for the design of a new 3.4 cell superconducting RF photo electron gun [2]. The paper presents details of different components of this gun, explains the status of manufacturing and gives results of first test measurements. Furthermore, the idea is discussed to use for emittance compensation instead of a static magnetic field which is inside the cavity of a normal conducting RF gun in the superconducting gun cavity an additional magnetic RF field (TE011 mode) . By computer simulation the attraction of this idea is demonstrated.