Keyword: power-supply
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MOPA22 Study on Electropolishing Conditions for 650 MHz Niobium SRF Cavity cavity, cathode, SRF, niobium 97
  • V. Chouhan, D.J. Bice, F. Furuta, M. Martinello, M.K. Ng, H. Park, T.J. Ring, G. Wu
    Fermilab, Batavia, Illinois, USA
  • B.M. Guilfoyle, M.P. Kelly, T. Reid
    ANL, Lemont, Illinois, USA
  The PIP II linear accelerator includes different types of niobium SRF cavities including 650 MHz elliptical low (0.61) and high (0.92) beta cavities. The elliptical cavity surface is processed with the electropolishing method. The elliptical cavities especially the low-beta 650 MHz cavities showed a rough equator surface after the EP was performed with the standard EP conditions. This work was focused to study the effect of different EP parameters, including cathode surface area, temperature and voltage, and optimize them to improve the cavity surface.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA22  
About • Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 03 September 2022
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MOPA43 Dee Voltage Regulator for the 88-Inch Cyclotron cyclotron, feedback, detector, controls 147
  • M. Kireeff, P. Bloemhard, T. Hassan, L. Phair
    LBNL, Berkeley, California, USA
  Funding: This work was supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC02-05CH11231
A new broadband Dee voltage regulator was designed and built for the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The previous regulator was obsolete, consequently, it was difficult to troubleshoot and repair. Additionally, during operation, it displayed problems of distortion and stability at certain frequencies. The new regulator uses off-the-shelf components that can detect and disable the RF during sparking events, protecting the RF driver system. Furthermore, it improves the tuning of the cyclotron and allows consistency in operation.
poster icon Poster MOPA43 [1.032 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA43  
About • Received ※ 02 August 2022 — Revised ※ 04 August 2022 — Accepted ※ 16 August 2022 — Issue date ※ 09 September 2022
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MOPA61 Modular Solid-State Switching and Arc Suppression for Vacuum Tube Bias Circuits high-voltage, vacuum, pulsed-power, operation 179
  • E.L. Atkinson, T.J. Houlahan, B.E. Jurczyk, R.A. Stubbers
    Starfire Industries LLC, Champaign, USA
  In this work, we present operational and performance data for a solid-state switching circuit that delivers pulsed power at up to 12 kV and 100 A. This circuit, which is comprised of a series configuration of IGBT-based subcircuits, is suitable for driving the high-power vacuum-tube amplifiers that are typically used in RF accelerator systems. Each subcircuit can switch up to 3 kV, and the subcircuits can be stacked in series to extend the overall voltage capabilities of the switch. The circuit is designed to prevent overvoltaging any single transistor during switching transients or faults, regardless of the number of series subcircuits. Further, the circuit also includes the capability for rapid arc detection and suppression. Testing has shown effective switching at up to 100 A at 12 kV and for pulse repetition frequencies and durations in the range of 1-200 Hz and 10-50 µs, respectively. Additionally, the arc suppression circuitry has been shown to reliably limit arcs at 8-12 kV with a quench time of <1 µs and with a total energy of <0.2 J, minimizing the grid erosion in the vacuum-tube during an arc.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA61  
About • Received ※ 01 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 20 August 2022 — Issue date ※ 10 September 2022
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TUPA29 Machine Learning for Predicting Power Supply Trips in Storage Rings storage-ring, network, quadrupole, sextupole 413
  • I. Lobach, M. Borland, G.I. Fystro, A. Sannibale, Y. Sun
    ANL, Lemont, Illinois, USA
  • A. Diaw, J.P. Edelen
    RadiaSoft LLC, Boulder, Colorado, USA
  Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
In the Advanced Photon Source (APS) storage ring at Argonne National Lab, trips in the magnet power supplies (PSs) lead to a complete electron beam loss a few times a year. This results in unexpected interruptions of the users’ experiments. In this contribution, we investigate the historical data for the last two decades to find precursors for the PS trips that could provide an advance notice for future trips and allow some preventive action by the ring operator or by the PS maintenance team. Various unsupervised anomaly detection models can be trained on the vast amounts of available reference data from the beamtime periods that ended with an intentional beam dump. We find that such models can sometimes detect trip precursors in PS currents, voltages, and in the temperatures of magnets, capacitors and transistors (components of PSs).
poster icon Poster TUPA29 [2.116 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA29  
About • Received ※ 03 August 2022 — Revised ※ 07 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 18 August 2022
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TUPA30 Development of a Compact 2D Carbon Beam Scanner for Cancer Therapy proton, simulation, magnet-design, radiation 417
  • B. Mustapha, A. Barcikowski, J.A. Nolen
    ANL, Lemont, Illinois, USA
  • V.P. Derenchuk, P. Osucha
    ProNova Solutions, Knoxville, USA
  • N. Tsoupas
    BNL, Upton, New York, USA
  Funding: This work was supported by the U.S. Department of Energy, under Contract No. DE-AC02-06CH11357. This research was support through the DOE’s Accelerator Stewardship program.
A novel trapezoidal coil 2D carbon beam scanner has been designed, and a prototype has been successfully developed and tested. The field performance of the magnet has been characterized and it is in excellent agreement with the simulations. A better than 1% field uniformity in both planes has been achieved within the useful aperture of the magnet. This represents a significant improvement over the prior art of the elephant-ear scanner design. A comparison of the two designs and the results from the new trapezoidal-coil design will be presented and discussed. Higher power and online beam testing are planned in the near future.
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA30  
About • Received ※ 25 July 2022 — Revised ※ 14 August 2022 — Accepted ※ 15 August 2022 — Issue date ※ 25 August 2022
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WEZD3 Magnetron R&D Progress for High Efficiency CW RF Sources of Industrial Accelerators injection, controls, feedback, experiment 597
  • H. Wang, K. Jordan, R.M. Nelson, S.A. Overstreet, R.A. Rimmer
    JLab, Newport News, Virginia, USA
  • J.N. Blum
    VCU, Richmond, Virginia, USA
  • B.R.L. Coriton, C.P. Moeller, K.A. Thackston
    GA, San Diego, California, USA
  • J.L. Vega
    The College of William and Mary, Williamsburg, Virginia, USA
  • G. Ziemyte
    UKY, Kentucky, USA
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177, and DOE OS/HEP Accelerator Stewardship award 2019-2022.
After the demonstration of using high efficiency magnetron power to combine and aim to drive a radio frequency accelerator at 2450MHz in CW mode [1], we have used trim coils adding to a water-cooled magnetron and three amplitude modulation methods in an open-loop control to further suppress the 120Hz side-band noise to -46.7dBc level. We have also successfully demonstrated the phase-locking to an industrial grade cooking magnetron transmitter at 915MHz with a 75kW CW power delivered to a water load by using a -26.6dBc injection signal. The sideband noise at 360Hz from the 3-Phase SCRs DC power supply can be reduced to -16.2dBc level. Their power combing scheme and higher power application to industrial accelerators are foreseeing.
[1] H. Wang, et al, Magnetron R&D for High Efficiency CW RF Sources for Industrial Accelerators, TUPAB348, 12th Int. Particle Acc. Conf. IPAC2021, Campinas, SP, Brazil.
slides icon Slides WEZD3 [3.074 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEZD3  
About • Received ※ 18 July 2022 — Revised ※ 25 July 2022 — Accepted ※ 08 August 2022 — Issue date ※ 11 August 2022
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WEPA16 A 500 kV Inverted Geometry Feedthrough for a High Voltage DC Electron Gun gun, high-voltage, electron, cathode 651
  • C. Hernandez-Garcia, D.B. Bullard, J.M. Grames, G.G. Palacios Serrano, M. Poelker
    JLab, Newport News, Virginia, USA
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177 and Office of Science Funding Opportunity LAB 20-2310 award PAMS-254442.
The Continuous Electron Beam Accelerator Facility injector at Jefferson Lab (JLab) utilizes an inverted-geometry ceramic insulator photogun operating at 130 kV direct current to generate spin-polarized electron beams for high-energy nuclear physics experiments. A second photogun delivers 180 keV beam for commissioning a SRF booster in a testbed accelerator, and a larger version delivers 300 keV magnetized beam in a test stand beam line. This contribution reports on the development of an unprecedented inverted-insulator with cable connector for reliably applying 500 kV DC to a future polarized beam photogun, to be designed for operating at 350 kV without field emission. Such a photogun design could then be used for generating a polarized electron beam to drive a spin-polarized positron source as a demonstrator for high energy nuclear physics at JLab. There are no commercial cable connectors that fit the large inverted insulators required for that voltage range. Our proposed concept is based on a modified epoxy receptacle with intervening SF6 layer and a test electrode in a vacuum vessel.
poster icon Poster WEPA16 [6.217 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA16  
About • Received ※ 03 August 2022 — Revised ※ 05 August 2022 — Accepted ※ 07 August 2022 — Issue date ※ 09 October 2022
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