Author: Quast, T.
Paper Title Page
TUPPD050 Investigation of Laser-cleaning Process on Lead Photocathodes 1515
 
  • S.G. Schubert, R. Barday, T. Kamps, T. Quast, A. Varykhalov
    HZB, Berlin, Germany
  • R. Nietubyć
    The Andrzej Soltan Institute for Nuclear Studies, Centre Świerk, Świerk/Otwock, Poland
  • F. Siewert
    BESSY GmbH, Berlin, Germany
  • J. Smedley
    BNL, Upton, Long Island, New York, USA
  • G. Weinberg
    FHI, Berlin, Germany
 
  Funding: Work supported by Bundesministerium für Bildung und Forschung and Land Berlin.
Metal photocathodes are widely used in electron injectors due to their stability and long life time; unfortunately they exhibit low quantum efficiency. Due to adsorption of contaminants the work function increases and thus the quantum efficiency is further reduced. In order to increase the quantum efficiency of our Pb cathode we performed a cleaning procedure by means of a high power excimer laser as suggested by Smedley*. The process was studied on witness samples in a combined photo emission, SEM and quantum efficiency measurement study. Thin Lead films were arc-deposited on optical polished Mo-substrates**. Before and after irradiation the sample was analyzed at 140 eV photon energy at a XPS/ARPES end station at the synchrotron radiation source Bessy II. We followed the change of the Pb 5d signals. In the initial situation we observed signals originating from metallic Pb and Pb in the oxidized state, respectively. Since the surface roughness is of concern for the injector performance it was examined before and after the irradiation procedure with white-light-interferometry and the surface morphology by means of SEM.
*J. Smedley et al, PRST-AB 11, 013502 (2008).
** Rao, T. et al., IPAC 2010, THPEC020 (2010).
 
 
MOPPP015 Status of the BERLinPro Energy Recovery Linac Project 601
 
  • J. Knobloch, M. Abo-Bakr, W. Anders, R. Barday, K. Bürkmann-Gehrlein, V. Dürr, S.C. Heßler, A. Jankowiak, T. Kamps, O. Kugeler, B.C. Kuske, P. Kuske, A.N. Matveenko, G. Meyer, R. Müller, A. Neumann, K. Ott, Y. Petenev, D. Pflückhahn, T. Quast, J. Rahn, S.G. Schubert
    HZB, Berlin, Germany
 
  Funding: Funding provided by the BMBF and the State of Berlin
In October 2010 Helmholtz Zentrum Berlin received funding to design and build the Berlin Energy Recovery Linac Project BERLinPro. The goal of this compact ERL is to develop the accelerator physics and technology required to generate and accelerate a 100-mA, 1 mm·mrad emittance beam. Given the flexibility of ERLs, other operation modes such as short-bunch operation will also be investigated. The BERLinPro technology and know-how can then be transferred to a variety of ERL-based applications. Presently, BERLinPro is in the design phase and the optics has been settled. Furthermore, first beam has been achieved with a superconducting RF photoinjector, which represents an important step towards realizing a CW injector for BERLinPro. An overview of the present status and the conceptual design report is presented.
 
 
TUPPD051 Operational Experience with the Nb/Pb SRF Photoelectron Gun 1518
 
  • T. Kamps, W. Anders, R. Barday, A. Jankowiak, J. Knobloch, O. Kugeler, A.N. Matveenko, A. Neumann, T. Quast, J. Rudolph, S.G. Schubert, J. Völker
    HZB, Berlin, Germany
  • P. Kneisel
    JLAB, Newport News, Virginia, USA
  • R. Nietubyć
    The Andrzej Soltan Institute for Nuclear Studies, Centre Świerk, Świerk/Otwock, Poland
  • J.K. Sekutowicz
    DESY, Hamburg, Germany
  • J. Smedley
    BNL, Upton, Long Island, New York, USA
  • J. Teichert
    HZDR, Dresden, Germany
  • V. Volkov
    BINP SB RAS, Novosibirsk, Russia
  • I. Will
    MBI, Berlin, Germany
 
  SRF photoelectron guns offer the promise of high brightness, high average current beam production for the next generation of accelerator driven light sources such as free electron lasers, THz radiation sources or energy-recovery linac driven synchrotron radiation sources. In a first step a fully superconducting RF (SRF) photoelectron gun is under development by a collaboration between HZB, DESY, JLAB, BNL and NCBJ. The aim of the experiment is to understand and improve the performance of a Nb SRF gun cavity coated with a small metallic Pb cathode film on the cavity backplane. This paper describes the highlights from the commissioning and beam parameter measurements. The main focus is on lessons learned from operation of the SRF gun.