Author: Cancelo, G.I.
Paper Title Page
MOPB077 Lorentz Force Detuning Compensation Studies for Long Pulses in ILC type SRF Cavities 354
  • N. Solyak, G.I. Cancelo, B. Chase, D.J. Crawford, D.R. Edstrom, Jr, E.R. Harms, Y.M. Pischalnikov, W. Schappert
    Fermilab, Batavia, USA
  Project-X 3-8 GeV pulsed linac is based on ILC type 1.3 GHz elliptical cavities. The cavity will operate at 25 MV/m accelerating gradient, but in contrast with XFEL and ILC projects the required loaded Q is much higher (Q=107) and RF pulse is much longer (~8ms). For these parameters Lorence force detuning (LFD) and microphonics should be controlled at the level <30 Hz. A new algorithm of LFD compensation, developed at Fermilab for ILC cavities was applied for Lorentz force compensation studies for 8ms pulses. In these studies two cavities inside TESLA-type cryomodule at Fermilab NML facility have been powered by one klystron. Studies done for different cavity gradients and different values of loaded Q demonstrated that required compensation are achievable. Detuning measurements and compensation results are presented.  
TUPB062 Longitudinal Dynamic Analysis for the Project X 3-8 GeV Pulsed Linac 618
  • G.I. Cancelo, B. Chase, Y.I. Eidelman, S. Nagaitsev, N. Solyak
    Fermilab, Batavia, USA
  The Pulsed Linac is a will require over 200 9-cell, 1300 MHz cavities packed in 26 ILC type cryomodules to accelerate 1 mA average beam current from 3GeV to 8 GeV. The architecture of the RF must optimize RF power, beam emittance, and energy gain amid a large number of requirement and constraints. The pulse length is a critical issue. Ideally, a 26 ms pulse would allow direct injection into the Fermilab’s Main Injector, bypassing the need of the Fermilab’s Recicler. High loaded quality factors (QL) are also desirable to minimize RF power. These requirements demand an accurate control of the cavity resonant frequency disturbed by Lorentz Force Detuning and microphonics. Also the LLRF control system must regulate the RF amplitude and phase within tight bounds amid a long list of dynamic disturbances. The present work describes the simulation efforts and measurements at Fermilab facilities.  
THPB085 LLRF Automation for the 9mA ILC Tests at FLASH 1023
  • J. Branlard, V. Ayvazyan, O. Hensler, H. Schlarb, Ch. Schmidt, N.J. Walker, M. Walla
    DESY, Hamburg, Germany
  • G.I. Cancelo, B. Chase
    Fermilab, Batavia, USA
  • J. Carwardine
    ANL, Argonne, USA
  • W. Cichalewski, W. Jałmużna
    TUL-DMCS, Łódź, Poland
  • S. Michizono
    KEK, Ibaraki, Japan
  Since 2009 and under the scope of the International Linear Collider (ILC) R&D, a series of studies takes place twice a year at the Free electron Laser accelerator in Hamburg, (FLASH) DESY, in order to investigate technical challenges related to the high-gradient, high-beam-current design of the ILC. Such issues as operating cavities near their quench limit with high beam loading or in klystron saturation regime are investigated, always pushing the limits of FLASH nominal operational conditions. To support these studies, a series of automation algorithms have been developed and implemented at DESY. These include automatic detection of cavity quenches, automatic adjustment of the superconducting cavity quality factor, and automatic compensation of detuning due to Lorentz forces. This paper explains the functionality of these automation tools, details about their implementation, and shows the experience acquired during the last 9mA ILC test which took place at DESY in February 2012. The benefit of these algorithms and the R&D results these automation tools have permitted will be clearly explained.