Author: Bratton, R.E.
Paper Title Page
TUPA59 RF System Upgrade for Low Energy DTL Cavity at LANSCE 478
  • J.T.M. Lyles, R.E. Bratton, T.W. Hall, M. Sanchez Barrueta
    LANL, Los Alamos, New Mexico, USA
  Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract 89233218CNA000001.
The Los Alamos Neutron Science Center (LANSCE) 100-MeV Drift Tube Linac (DTL) uses four accelerating cavities. In May of 2021, a new RF amplifier system was commissioned to drive the first 4-MeV cavity. It had been powered for 30 years with a triode vacuum tube RF amplifier driven by a tetrode, along with four more vacuum tubes for anode high-voltage modulation. The new amplifier system uses one tetrode amplifier driven by a 20-kW solid state amplifier (SSA) to generate 400 kWp at 201.25 MHz. The tetrode amplifier is protected for reflected power from the DTL by a coaxial circulator. The new installation includes cRio controls and a fast protection and monitoring system capable of reacting to faults within 10 µs. A new digital low-level RF (LLRF) system has been installed that integrates I/Q signal processing, PI feedback, and feedforward controls for beam loading compensation. Issues with LLRF stability were initially encountered due to interaction from thermal-related RF phase changes. After these issues were solved, the final outcome has been a reliable new RF system to complete the overall upgrade of the LANSCE DTL RF power plant.
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA59  
About • Received ※ 03 August 2022 — Revised ※ 04 August 2022 — Accepted ※ 06 August 2022 — Issue date ※ 12 August 2022
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