Experimental Safe Extremum Seeking for Accelerators

Williams, Alan Brian; Scheinker, Alexander; Huang, En-Chuan; Taylor, Charles Edward; Krstic, Miroslav

doi:10.1109/tcst.2024.3377828

This content will become publicly available on Sat Mar 22 00:00:00 EDT 2025

Title: Experimental Safe Extremum Seeking for Accelerators

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Abstract

Here, we demonstrate the recent designs of safe extremum seeking (Safe ES) on the 1-km-long charged particle accelerator at the Los Alamos Neutron Science Center (LANSCE). Safe ES is a modification of extremum seeking (ES) which, in addition to minimizing an analytically unknown cost, also employs a safety filter based on an analytically unknown control barrier function (CBF) safety metric. Tuning is necessitated by accelerators being large complex systems, with many drifting parameters due to thermal effects and degradation. At the same time, safe operation (the maintenance of state constraints) is crucial, as damage brings astronomical costs, both financially and in operation downtime. Our measured (but analytically unknown) safety metric is the beam current. We perform multivariable Safe ES on three accelerator applications, in which we adapt 4, 6, and 3 magnet strength parameters, respectively. Two of the three applications are for validated simulation models of beamlines at LANSCE: the first for the proton radiography (pRad) beamline of 800-MeV protons for spot size tuning; the second on a high-performance code, HPSim, for tuning the low-energy beam transport (LEBT) region that contains a beam of 750-keV protons. The third is an experimental tuning of the steering magnets in the LEBT atmore » LANSCE.« less

Authors:

^[1];

^[2];

^[3]

Univ. of San Diego, San Diego, CA (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Univ. of San Diego, San Diego, CA (United States)

Publication Date:: Fri Mar 22 00:00:00 EDT 2024

Research Org.:: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:: USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:: 2332792

Report Number(s):: LA-UR-23-29586
Journal ID: ISSN 1063-6536

Grant/Contract Number:: 89233218CNA000001

Resource Type:: Accepted Manuscript

Journal Name:: IEEE Transactions on Control Systems Technology

Additional Journal Information:: Journal Name: IEEE Transactions on Control Systems Technology; Journal ID: ISSN 1063-6536

Publisher:: IEEE

Country of Publication:: United States

Language:: English

Subject:: Particle beams; Tuning; Safety; Particle accelerators; Optimization; Heuristic algorithms; Linear particle accelerator; Particle beam handling; Robust control; Time-varying systems

Citation Formats


                    Williams, Alan Brian, Scheinker, Alexander, Huang, En-Chuan, Taylor, Charles Edward, and Krstic, Miroslav. Experimental Safe Extremum Seeking for Accelerators.  United States: N. p., 2024. 
Web.  doi:10.1109/tcst.2024.3377828.

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                    Williams, Alan Brian, Scheinker, Alexander, Huang, En-Chuan, Taylor, Charles Edward, & Krstic, Miroslav. Experimental Safe Extremum Seeking for Accelerators.  United States.  https://doi.org/10.1109/tcst.2024.3377828

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                    Williams, Alan Brian, Scheinker, Alexander, Huang, En-Chuan, Taylor, Charles Edward, and Krstic, Miroslav. Fri .  
"Experimental Safe Extremum Seeking for Accelerators".  United States.  https://doi.org/10.1109/tcst.2024.3377828.

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@article{osti_2332792,

  title        = {Experimental Safe Extremum Seeking for Accelerators},

  author       = {Williams, Alan Brian and Scheinker, Alexander and Huang, En-Chuan and Taylor, Charles Edward and Krstic, Miroslav},

  abstractNote = {Here, we demonstrate the recent designs of safe extremum seeking (Safe ES) on the 1-km-long charged particle accelerator at the Los Alamos Neutron Science Center (LANSCE). Safe ES is a modification of extremum seeking (ES) which, in addition to minimizing an analytically unknown cost, also employs a safety filter based on an analytically unknown control barrier function (CBF) safety metric. Tuning is necessitated by accelerators being large complex systems, with many drifting parameters due to thermal effects and degradation. At the same time, safe operation (the maintenance of state constraints) is crucial, as damage brings astronomical costs, both financially and in operation downtime. Our measured (but analytically unknown) safety metric is the beam current. We perform multivariable Safe ES on three accelerator applications, in which we adapt 4, 6, and 3 magnet strength parameters, respectively. Two of the three applications are for validated simulation models of beamlines at LANSCE: the first for the proton radiography (pRad) beamline of 800-MeV protons for spot size tuning; the second on a high-performance code, HPSim, for tuning the low-energy beam transport (LEBT) region that contains a beam of 750-keV protons. The third is an experimental tuning of the steering magnets in the LEBT at LANSCE.},

  doi          = {10.1109/tcst.2024.3377828},

  journal      = {IEEE Transactions on Control Systems Technology},

  number       = ,

  volume       = ,

  place        = {United States},

  year         = {Fri Mar 22 00:00:00 EDT 2024},

  month        = {Fri Mar 22 00:00:00 EDT 2024}

}

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