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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