Author: Lyles, J.T.M.
Paper Title Page
WEPAL046 A New Digital Feedback and Feedforward Controller for Cavity Field Control of the LANSCE Accelerator 2277
 
  • S. Kwon, L.J. Castellano, D.J. Knapp, J.T.M. Lyles, M.S. Prokop, A. Scheinker, P.A. Torrez
    LANL, Los Alamos, New Mexico, USA
 
  Funding: Work Supported by DOE
A new digital low-level RF system was designed and has been deployed on the drift-tube-linac section of the Los Alamos Neutron Science Center(LANSCE) proton accelerator. This new system is part of a modernization of the existing analog cavity-field controls that were originally developed and put into service forty-five years ago. For stabilization of the cavity field amplitude and phase during beam loading, a proportional-integral feedback controller, a static beam feedforward controller, and an iterative learning controller working in parallel have been implemented. In this paper, the controller architecture is described, and the performances of the three controllers when beam is being actively accelerated is presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL046  
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THPAL025 New Drift-Tube Linac RF Systems at LANSCE 3680
 
  • J.T.M. Lyles, R.E. Bratton, M.S. Prokop, D. Rees
    LANL, Los Alamos, New Mexico, USA
 
  Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396.
LANSCE has restored the proton drift-tube linac (DTL) to high-power capability after the original RF-power tube manufacturer could no longer supply devices that consistently met our high-average power requirement. Thales TH628L Diacrodes® now supply RF power to three of the four DTL tanks. These tetrodes reused the existing infrastructure including water-cooling systems, coaxial transmission lines, high-voltage power supplies and capacitor banks. Each transmitter uses a combined pair of power amplifiers to produce up to 3- MW peak and 360- kW of mean power. A new intermediate power amplifier was simultaneously developed using a TH781 tetrode. Design and prototype testing of the high-power stages was completed in 2012, with commercialization following in 2013. Each installation was accomplished during a 4 to 5 month beam outage each year from 2014-2016. A new digital low-level RF control system was designed, built and placed into operation in 2016. The interaction of the dual power amplifiers, the I/Q LLRF, and the DTL cavities provided many challenges that were overcome. The replacement RF systems have completely met our accelerator requirements.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL025  
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