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Pappas, G. C.

Paper Title Page
TUPMN029 Linac Upgrading Program for the Fermi Project : Status and Perspectives 977
  • G. D'Auria, D. Bacescu, L. Badano, C. Bontoiu, F. Cianciosi, P. Craievich, M. B. Danailov, S. Di Mitri, M. Ferianis, G. C. Pappas, G. Penco, A. Rohlev, A. Rubino, L. Rumiz, S. Spampinati, M. Trovo, A. Turchet, D. Wang
    ELETTRA, Basovizza, Trieste
  FERMI@ELETTRA is a soft X-ray forth generation light source under development at the ELETTRA laboratory. It will be based on the existing 1.0 GeV Linac, revised and upgraded to fulfil the stringent requirements expected from the machine. The overall time schedule of the project is very tight and ambitious, foreseeing to supply 10 nm photons to users within 2010. Here the machine upgrading program and the ongoing activities are presented and discussed.  
WEPMS028 Converter-Modulator Design and Operations for the ILC L-band Test Stand 2397
  • W. Reass
    LANL, Los Alamos, New Mexico
  • C. Adolphsen, T. G. Beukers, C. Burkhart, R. L. Cassel, M. N. Nguyen, G. C. Pappas, R. Swent, A. C. de Lira
    SLAC, Menlo Park, California
  • D. E. Anderson
    ORNL, Oak Ridge, Tennessee
  Funding: This work supported by Stanford Linear Accelerator Center, Oak Ridge National Laboratory, and the Department of Energy.

To facilitate a rapid response to the International Linear Collider (ILC) L-Band development program at SLAC, a spare converter-modulator was shipped from Los Alamos. This modulator was to be a spare for the Spallation Neutron Source (SNS) accelerator at ORNL. The ILC application requires a 33% higher peak output power (15 MW) and output current (130 Amp). This presents significant design challenges to modify the existing hardware and yet maintain switching parameters and thermal cycling within the semiconductor component ratings. To minimize IGBT commutation and free-wheeling diode currents, a different set of optimizations, as compared to the SNS design, were used to tune the resonant switching networks. Additional complexities arose as nanocrystalline cores with different performance characteristics (as compared to SNS), were used to fabricate the resonant "boost" transformers. This paper will describe the electrical design, system modifications, modeling efforts, and resulting electrical performance as implemented for the ILC L-band test stand.

WEPMS045 Power Modulators for FERMI Linac's Klystrons. 2448
  • G. C. Pappas
    SLAC, Menlo Park, California
  • G. D'Auria, P. Delgiusto, L. Veljak
    ELETTRA, Basovizza, Trieste
  The conventional line type modulators used for ELETTRA will have to be replaced for FERMI due to the increase in the pulse repetition frequency (PRF) from 10 to 50 Hz. The requirements for the FERMI modulator are as follows. The klystron used is a Thales TH2132 with a microperviance of 1.9-2.1 uA/V**(3/2). The peak voltage from the modulator is 320 kV, and the current is 350 A. The pulse width is 4.5 us, with a PRF of 50 Hz. Flat top should be better than ?0.5 % of the peak voltage. Prototypes for an upgraded line type modulator and a solid state induction type modulator[1] are in fabrication. The solid state design uses eight induction cells, each cell driven by two parallel Insulated Gate Bipolar Transistors (IGBT). Each IGBT will power a METGLAS 2605CO core with 4 kV and 3 kA for up to 5 us. A single turn is passed through the aperture of each of the cells, inductively adding the pulse voltages. The output from the modulator is then fed to a conventional pulse transformer to reach the 320 kV requirement. This paper presents the system design of both modulator types as well as details of the IGBT drivers, control electronics, IGBT and klystron protection and test data.

1. "NLC Hybrdi Solid State Induction Modulator" R. L. Cassel, etal, Lubeck, Germany, Linac 2004.