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Ratti, A.

Paper Title Page
TUP005 Design of an RFQ-Based Neutron Source for Cargo Container Interrogation 253
 
  • J. W. Staples, M. D. Hoff, J. W. Kwan, D. Li, B. A. Ludewigt, A. Ratti, S. P. Virostek, R. Wells
    LBNL, Berkeley, California
 
  An RFQ-based neutron generator system is described that generates pulsed neutrons for the active screening of sea-land cargo containers for the detection of shielded special nuclear materials (SNM). A microwave-driven deuteron source is coupled to an electrostatic LEBT that injects a 40 mA D+-beam into a 6 MeV, 5.1 meter-long 200 MHz RFQ. The RFQ has a unique beam dynamics design and is capable of operating at duty factors of 5 to10% accelerating a D+ time-averaged current of up to 1.5 mA at 5% duty factor, including species and transmission loss. The beam is transported through a specially-designed thin-window into a 2-atmosphere deuterium gas target. A high-frequency dipole magnet is used to scan the beam over the long dimension of the 5 by 40 cm target window. The source will be capable of delivering a neutron flux of 2·107 n/(cm2·s) to the center of a cargo container. Details of the ion source, LEBT, RFQ beam dynamics and gas target design are presented.  
MOP015 Linac Design for the FERMI Project 61
 
  • G. D'Auria, P. Craievich, P. Delgiusto, S. Di Mitri, M. Ferianis, E. Menotti, M. M. Milloch, G. C. Pappas, G. Penco, M. Trovo
    ELETTRA, Basovizza, Trieste
  • L. R. Doolittle, A. Ratti
    LBNL, Berkeley, California
 
  FERMI is a fourth generation light source under construction at Sincrotrone Trieste. This is based upon the conversion of the existing injector linac to a 1.2 GeV machine suitable to drive a seeded FEL. The linac will require significant improvements and the addition of several new accelerating modules. Important parameters are pulse to pulse energy stability and the jitter of the e-bunch time of arrival. This paper will cover the baseline design of the machine, as well as experimental results and the proposed technical solutions for the more critical sub-systems.  
THP005 Digital Control of Cavity Fields in the Spallation Neutron Source Superconducting Linac 571
 
  • H. Ma, M. S. Champion, M. T. Crofford, K.-U. Kasemir, M. F. Piller
    ORNL, Oak Ridge, Tennessee
  • A. Brandt
    DESY, Hamburg
  • L. R. Doolittle, A. Ratti
    LBNL, Berkeley, California
 
  Control of the pulsed RF cavity fields in the Spallation Neutron Source (SNS) superconducting Linac uses both the real-time feedback regulation and the pulse-to-pulse adaptive feed-forward compensation. This control combination is required to deal with the typical issues associated with superconducting cavities, such as the Lorentz force detuning, mechanical resonance modes, and cavity filling. The all-digital implementation of this system provides the capabilities and flexibility necessary for achieving the required performance, and to accommodate the needs of various control schemes. The low-latency design of the digital hardware has successfully produced a wide control bandwidth, and the developed adaptive feed forward algorithms have proved to be essential for the controlled cavity filling, the suppression of the cavity mechanical resonances, and the beam loading compensation. As of this time, all 96 LLRF systems throughout the Linac have been commissioned and are in operation.  
THP007 Timing Distribution in Accelerators via Stabilized Optical Fiber Links 577
 
  • J. M. Byrd, L. R. Doolittle, A. Ratti, J. W. Staples, R. B. Wilcox
    LBNL, Berkeley, California
 
  We present progress on fiber-optic based systems for highly stable distribution of timing signals for accelerators. This system has application for linac-based sources of ultrafast radiation which require sub-100 fsec synchronization or for very large accelerators such as the linear collider. The system is based on optical fiber links that are stabilized with an optical interferometer with RF and timing signals distributed as modulations on the optical carrier. We present measurements of the stability of this link over distances of several hundred meters and discuss issues for testing the link over 10 km.