Keyword: DTL
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MOPA41 Diagnostics for LINAC Optimization with Machine Learning linac, network, controls, diagnostics 139
  • R.V. Sharankova, M.W. Mwaniki, K. Seiya, M.E. Wesley
    Fermilab, Batavia, Illinois, USA
  The Fermilab Linac delivers 400 MeV H beam to the rest of the accelerator chain. Providing stable intensity, energy, and emittance is key since it directly affects downstream machines. To operate high current beam, accelerators must minimize uncontrolled particle loss; this is generally accomplished by minimizing beam emittance. Ambient temperature and humidity variations are known to affect resonance frequency of the accelerating cavities which induces emittance growth. In addition, the energy and phase space distribution of particles emerging from the ion source are subject to fluctuations. To counter these effects we are working on implementing dynamic longitudinal parameter optimization based on Machine Learning (ML). As an input for the ML model, signals from beam diagnostic have to be well understand and reliable. We have been revisiting diagnostics in the linac. In this presentation we discuss the status of the diagnostics and beam studies as well as the status and plans for ML-based optimization.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA41  
About • Received ※ 05 August 2022 — Accepted ※ 06 August 2022 — Issue date ※ 07 September 2022  
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TUPA44 A Personal History of the Development of the LAMPF/LANSCE Accelerator coupling, linac, operation, drift-tube-linac 449
  • J.M. Potter
    JP Accelerator Works, Los Alamos, New Mexico, USA
  The LAMPF/LANSCE accelerator has now been operational for 50 years. I arrived as a LASL employee in Group P11 in April 1964 at the beginning stages of its development. I participated in the development of the resonant coupling principle [1] and went on to develop tuning procedures for the 805-MHz coupled cavity linac (CCL) structures and the post-stabilized drift tube linac (DTL) [2]. The resonant coupling principle is now well established as the basis for rf linear accelerators worldwide. I will discuss the development and building of the accelerator from my viewpoint as a member of a large, dedicated team of physicists, engineers, technicians, and support personnel.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA44  
About • Received ※ 02 August 2022 — Revised ※ 04 August 2022 — Accepted ※ 05 August 2022 — Issue date ※ 05 September 2022
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TUPA52 Initial Results of the 201.25 MHz Coaxial Window Test Stand multipactoring, Windows, vacuum, electron 458
  • T.W. Hall, J.T.M. Lyles, A. Poudel, A.S. Waghmare
    LANL, Los Alamos, New Mexico, USA
  We have recently commissioned an RF window test stand for the Drift Tube Linear Accelerator (DTL) portion of the Los Alamos Neutron Science Center (LANSCE). The window test stand consists of two RF windows that create a vacuum chamber which allows the windows to be tested to the peak power levels used in the DTL. Initial results clearly indicated multipactoring due to the increase of pressure at specific regions of peak forward power levels. Temperature measured at various azimuthal locations on both windows showed increased multipactor heating on the downstream window versus the upstream window. We present the effect of the titanium nitride coating that is presently applied to windows on both multipactor and window temperature. These results are discussed with respect to their impact on the LANSCE DTL performance.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA52  
About • Received ※ 25 July 2022 — Revised ※ 04 August 2022 — Accepted ※ 05 August 2022 — Issue date ※ 07 September 2022
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TUPA59 RF System Upgrade for Low Energy DTL Cavity at LANSCE controls, LLRF, cavity, MMI 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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WEPA42 A Modular X-Ray Detector for Beamline Diagnostics at LANL detector, diagnostics, shielding, electron 725
  • P.M. Freeman, B. Odegard, R. Schmitz, D. Stuart, J. Yang
    UCSB, Santa Barbara, California, USA
  • J. Bohon, M.S. Gulley, E.-C. Huang, J. Smedley
    LANL, Los Alamos, New Mexico, USA
  • L. Malavasi
    WPI, Worcester, MA, USA
  An X-ray detector is being developed for diagnostic measurement and monitoring of the Drift Tube LINAC (DTL) at the Los Alamos Neutron Science Center (LANSCE) at Los Alamos National Lab. The detector will consist of a row of x-ray spectrometers adjacent to the DTL that will measure the spectrum of X-rays resulting from bremsstrahlung of electrons created in vacuum by the RF. Each spectrometer will monitor a specific gap between drift tubes, and will consist of an array of scintillating crystals coupled to SiPMs read out with custom-built electronics. The spectrometer is designed with one LYSO and three NaI crystals. The LYSO provides a tagged gamma source with three peaks that are used for calibration of the NaI. A prototype of the spectrometer was tested at the LANSCE DTL to validate the feasibility of measuring gamma spectra and performing self-calibration in situ. A summary of test results with the LANSCE prototype will be presented, along with a detector system design that aims to be modular and inexpensive across all modules in the DTL. Plans for future development will be presented as well.  
poster icon Poster WEPA42 [1.308 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA42  
About • Received ※ 04 August 2022 — Revised ※ 06 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 11 August 2022
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