Keyword: beam-loading
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TUPA58 Iterative Tuning of the Beam Feedforward Controller for LANSCE LINAC Digital Low Level RF Control System controls, cavity, LLRF, neutron 475
  • S. Kwon, A.T. Archuleta, L.J. Castellano, M.S. Prokop, C. Rose, P.A. Torrez, P. Van Rooy
    LANL, Los Alamos, New Mexico, USA
  Funding: USDOE
This paper addresses an iterative particle beam phase and amplitude feedforward controller tuning method based on the gradient search approach. The method does not need an a priori plant model as it only needs data collected in previous experimental runs. The controller is implemented on a field programmable gate array (FPGA) equipped with a real-time operating system and a network connection. Data from each RF pulse is collected and sent via the network to the FPGA for processing. The controller tuning is performed between the RF pulses. Once the tuning is performed, the controller parameters are downloaded to the controller in the FPGA and new controller parameters are applied at the upcoming RF pulse
poster icon Poster TUPA58 [0.998 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA58  
About • Received ※ 01 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 07 September 2022
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WEPA63 Extensions of the Complex (IQ) Baseband RF Cavity Model Including RF Source and Beam Interactions cavity, controls, simulation, linac 767
  • S.P. Jachim, B.J. Cook, J.R.S. Falconer
    Arizona State University, Tempe, USA
  Funding: This work was supported in part by NSF award #1935994.
This paper extends prior work describing a complex envelope (i.e., baseband) dynamic model of excited accelerator RF cavities, including the effects of frequency detuning, beam loading, reflections, multiple drive ports, and parasitic modes. This model is presented here in closed-form transfer function and state-variable realizations, which may be more appropriate for analytic purposes. Several example simulations illustrate the detailed insight into RF system behavior afforded by this model.
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA63  
About • Received ※ 28 July 2022 — Revised ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 15 August 2022
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WEPA76 Radio Frequency System of the NSLS-II Injector LINAC for Multi-Bunch-Mode Beams controls, linac, klystron, operation 813
  • H. Ma, J. Rose, C. Sorrentino
    BNL, Upton, New York, USA
  Funding: US DOE, Office of BES
The Multi-Bunch Mode (MBM) beam injection opera-tion of NSLS-II LINAC requires a beam-loading compen-sation for its rf field. That requirement has a significant impact on its radio frequency system (RF), in both the low-level rf control and the high-power klystron transmit-ters. Specifically, for the rf control, it requires the output vector modulation have enough bandwidth to be able to respond the transients by the MBM beam of 40~300 nS long. For the high-power rf transmitters, it requires the klystrons to operate in a near-linear region to be able to respond the linear rf control for the beam-loading compensation, which means a need of ~30% extra rf power overhead, compared to the single-bunch mode operations. The digital signal processing and the network configuration for the rf controllers are also the important areas in the implementation. The original system design was driven by the MBM beam operation requirements, and our system upgrade today continues to be guided by the same principles.
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA76  
About • Received ※ 03 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 24 August 2022
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