Author: Garnett, R.W.
Paper Title Page
TUPTS009 Operating the SNS RF H Ion Source with a 10% Duty Factor 1951
  • M.P. Stockli, M.E. Clemmer, S.M. Cousineau, B. Han, T.A. Justice, Y.W. Kang, S.N. Murray, T.R. Pennisi, C. Piller, R.F. Welton
    ORNL, Oak Ridge, Tennessee, USA
  • I.N. Draganic, R.W. Garnett, D. Kleinjan, G. Rouleau
    LANL, Los Alamos, New Mexico, USA
  • V.G. Dudnikov
    Muons, Inc, Illinois, USA
  • C. Stinson
    ORNL RAD, Oak Ridge, Tennessee, USA
  Funding: This work was performed at Oak Ridge National Laboratory under contract DE-AC05-00OR22725 and at Los Alamos National Laboratory under contract DE-AC52-06NA25396 for the U.S. Department of Energy.
The SNS (Spallation Neutron Source) (radio-frequency) RF-driven, H ion source injects ~50 mA of H beam into the SNS accelerator at 60 Hz with a 6% duty factor. It injects up to 7 A·hrs of H ions during its ~14-week service cycles, which is an unprecedented lifetime for small-emittance, high-current pulsed H ion sources. The SNS source also features unprecedented low cesium consumption and can be installed and started up in <10 h. Presently, the LANSCE (Los Alamos Neutron Science CEnter) accelerator complex in Los Alamos is fed by a filament-driven, biased converter-type H source that operates with a high plasma duty factor of 10%. It needs to be replaced every 4 weeks with a ~4 day startup phase. The measured negative beam current of 16-18 mA falls below the desired 21 mA acceptance of LANSCE’s accelerator especially since the beam contains several mA of electrons. LANSCE and SNS are exploring the possibility of using the SNS RF H source at LANSCE to increase the H beam current and the ion source lifetime while decreasing the startup time. For this purpose, the SNS H source has been tested at a 10% duty factor by operating it at 120 Hz with 840 µs plasma pulses generated with ~30 kW of 2 MHz RF power, and extracting ~25 mA around-the-clock for 28 days. This, and additional tests and other considerations are discussed in this paper.
DOI • reference for this paper ※  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPTS103 First Results of the Analytical Method Used to Reduce Downtime Risk at an Accelerator Facility 4349
  • W.C. Barkley, M.J. Borden, R.W. Garnett, M.S. Gulley, E.L. Kerstiens, M. Pieck, D. Rees, F.E. Shelley, B.G. Smith
    LANL, Los Alamos, New Mexico, USA
  Funding: DOE
The Los Alamos Neutron Science Center (LANSCE), like many other accelerator facilities, was built decades ago and has been repurposed when new missions were adopted. With an ongoing beam availability expectation of at least 80% delivered to the Experimental Areas (EAs), a balance between cost of spare equipment and budget has always been a challenge. Beam availability data has been meticulously captured and binned over the years to completely characterize the Structures, Systems and Components (SSCs) and other factors that have caused or contributed to accelerator downtime. Over these years, a critical spares list prioritized the spare equipment purchases that were deemed most critical by the management team. In the span of the years 2013 ’ 2015, significant accelerator upgrades and equipment replacements were performed in a set of activities known as LANSCE-RM. Last year, a new risk-based approach was developed by the management team that included an analytical assessment and a quantitative evaluation of probability and consequence. The resulting risk register (risk-based equipment list) is being used to guide decisions on funding requests and provide justification to mitigate operational risks. A paper by the same authors was published at LINAC 2018 describing this risk-based approach that serves to reformulate the critical spares list. This paper, in the sections that follow, expands on the approach by detailing the specific results of the analyses that led to the first risk register. Additionally, it evaluates the historical beam downtime at LANSCE compared to the current funding allocation choices made to increase the reliability.
DOI • reference for this paper ※  
About • paper received ※ 10 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)