A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z    

Doolittle, L.R.

Paper Title Page
WPAT057 Overview of the Spallation Neutron Source Linac Low-Level RF Control System 3396
 
  • M. Champion, M.T. Crofford, K.-U. Kasemir, H. Ma, M.F. Piller
    ORNL, Oak Ridge, Tennessee
  • L.R. Doolittle, A. Ratti
    LBNL, Berkeley, California
 
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.

The design and production of the Spallation Neutron Source Linac Low-Level RF control system is complete, and installation will be finished in Spring 2005. The warm linac beam commissioning run in Fall 2004 was the most extensive test to date of the LLRF control system, with fourteen (of an eventual 96) systems operating simultaneously. In this paper we present an overview of the LLRF control system, the experience in designing, building and installing the system, and operational results.

 
WPAT060 SNS Low-Level RF Control System: Design and Performance 3479
 
  • H. Ma, M. Champion, M.T. Crofford, K.-U. Kasemir, M.F. Piller
    ORNL, Oak Ridge, Tennessee
  • L.R. Doolittle, A. Ratti
    LBNL, Berkeley, California
 
  Funding: ORNL managed by UT-Battelle for US DOE.

A full digital Low-Level RF controller has been developed for SNS LINAC. Its design is a good example of a modern digital implementation of the classic control theory. The digital hardware for all the control and DSP functionalities, including the final vector modulation, is implemented on a single high-density FPGA. Two models for the digital hardware have been written in VHDL and Verilog respectively, based on a very low latency control algorithm, and both have been being used for supporting the testing and commissioning the LINAC to the date. During the commissioning, the flexibility and ability for precise controls that only digital design on a larger FPGA can offer has proved to be a necessity for meeting the great challenge of a high-power pulsed SCL.

 
WPAT062 The Spallation Neutron Source RF Reference System 3573
 
  • M.F. Piller, M. Champion, M.T. Crofford, H. Ma
    ORNL, Oak Ridge, Tennessee
  • L.R. Doolittle
    LBNL, Berkeley, California
 
  The Spallation Neutron Source (SNS) RF Reference System includes the master oscillator (MO), local oscillator(LO) distribution, and Reference RF distribution systems. Coherent low noise Reference RF signals provide the ability to control the phase relationships between the fields in the front-end and linear accelerator (linac) RF cavity structures. The SNS RF Reference System requirements, implementation details, and performance are discussed.  
RPAT074 PEP-II Transverse Feedback Electronics Upgrade 3928
 
  • J.M. Weber, M.J. Chin, L.R. Doolittle
    LBNL, Berkeley, California
  • R. Akre
    SLAC, Menlo Park, California
 
  Funding: Supported by the U.S. Department of Energy under contract No. DE-AC03-76SF00098 (LBNL) and DE-AC03-76SF00515 (SLAC).

The PEP-II B Factory at the Stanford Linear Accelerator Center (SLAC) requires an upgrade of the transverse feedback system electronics. The new electronics require 12-bit resolution and a minimum sampling rate of 238 Msps. A Field Programmable Gate Array (FPGA) is used to implement the feedback algorithm. The FPGA also contains an embedded PowerPC 405 (PPC-405) processor to run control system interface software for data retrieval, diagnostics, and system monitoring. The design of this system is based on the Xilinx® ML300 Development Platform, a circuit board set containing an FPGA with an embedded processor, a large memory bank, and other peripherals. This paper discusses the design of a digital feedback system based on an FPGA with an embedded processor. Discussion will include specifications, component selection, and integration with the ML300 design.