H− ion source research and development at the Oak Ridge National Laboratory

Welton, R. F.; Stöckli, M. P.; Han, Binghong; Murray, S. N.; Pennisi, Terry R; Stinson, Chris; Aleksandrov, A.; Piller, C.; Kang, Y.; Tarvainen, O.

doi:10.1063/5.0057549

Cited by 10 publications

(16 citation statements)

References 15 publications

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“…Over the years, many improvements have been made to both the SNS internal [3] and external [7] antenna ion sources and are too extensive to discuss here. Looking forward, we are trying to minimize minor physical differences between the production ion source and spare sources.…”

Section: The Sns Cs-enhanced Rf-driven Multicusp Hion Sourcementioning

confidence: 99%

“…We also plan to explore incremental improvements in beam intensity by testing slightly larger outlet apertures as well as improving electron management by implementing filter circuits and improved power supplies. Development of the external-antenna ion source also continues as a contingency source for the SNS should any issues with the internal antennas reemerge [7]. Development of this source now focuses on standardizing build quality of the source and improving the reliability of plasma ignition [4].…”

Section: The Sns Cs-enhanced Rf-driven Multicusp Hion Sourcementioning

confidence: 99%

“…In the past several years and under high duty-factors of 5% and 10% (60/120 Hz x 840 μs), several issues with the converter ion source were observed and attempts made to resolve them. The issues included: (1) modest Hcurrent in range 12 -14 mA (no electrons), (2) limited source lifetimes, i.e., 4 weeks or shorter with filaments failures, (3) long rise-time of the arc discharge (<180 μs) that reduces the usable Hpulse length, (3) beam instability associated with frequent 80 kV arc downs (every few minutes), (4) larger-than-expected transverse, normalized, RMS emittances, > 0.2 π mm mrad, (5) 4 days of beam downtime for a source exchange, full Cs transfer to achieve production beam-intensity levels, (6) excessive high energy (voltage) droops over the beam pulse (~1-2 keV), (7) significant equipment failures due to numerous HV arc breakdowns, (8) low beam stability and low charge per pulse to all Huser facilities. In recent beam production cycles, however, incremental performance improvements were achieved for the negative ion injector, linear accelerator, and proton storage ring including: (1) average production currents now range from 15 -16.7 mA, (2) Extracted peak beam currents in the range 17 -18.5 mA during beam development times, (3) demonstrated W-filament lifetimes of 5 weeks (DF=10%) and 6 weeks (DF=5%), ( 4) Improved Hbeam stability with 3-5 hours between 80 kV arc downs, (5) reduced high voltage droops now < 500V over the full macro pulse, (6) average current injected into PSR over <120 μA, (7) no major equipment failures due to reduced HV breakdowns.…”

Section: The Lanl Surface Converter Hion Sourcementioning

confidence: 99%

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Negative hydrogen ion sources for particle accelerators: Sustainability issues and recent improvements in long-term operations

Welton

Bollinger

Dehnel

et al. 2022

J. Phys.: Conf. Ser.

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High brightness, negative hydrogen ion sources are used extensively in scientific facilities operating worldwide. Negative hydrogen beams have become the preferred means of filling circular accelerators and storage rings as well as enabling efficient extraction from cyclotrons. Several well-known facilities now have considerable experience with operating a variety of sources such as RF-, filament-, magnetron- and Penning-type H- ion sources. These facilities include the US Spallation Neutron Source (SNS), Japan Proton Accelerator Research Complex (J-PARC), Rutherford Appleton Laboratory (RAL-ISIS), Los Alamos Neutron Science Center (LANSCE), Fermi National Accelerator Laboratory (FNAL), Brookhaven National Laboratory (BNL), numerous installations of D-Pace (licenced by TRIUMF) ion sources used mainly on cyclotrons and, most recently, the CERN-LINAC-1 injector. This report first summarizes the current performance of these ion sources in routine, daily operations with attention toward source service-periods and availability metrics. Sustainability issues encountered at each facility are also reported and categorized to identify areas of common concern and key issues. Recent ion source improvements to address these issues are also discussed as well as plans for meeting future facility upgrade requirements.

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Section: The Sns Cs-enhanced Rf-driven Multicusp Hion Sourcementioning

confidence: 99%

Section: The Sns Cs-enhanced Rf-driven Multicusp Hion Sourcementioning

confidence: 99%

Section: The Lanl Surface Converter Hion Sourcementioning

confidence: 99%

See 1 more Smart Citation

Negative hydrogen ion sources for particle accelerators: Sustainability issues and recent improvements in long-term operations

Welton

Bollinger

Dehnel

et al. 2022

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

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“…A DC, 800 V electron gun had limited lifetime of ~2 weeks due to cathode sputtering or surface degradation. An RF assisted DC gun allowed lower voltage to start with, but the voltage had to be increased over time still beyond the cathode sputter threshold [5]. Recently, a pulsed DC gun (60Hz, 500 Ps) was successfully tested with ~2 kV for ~90 days on a test bench.…”

Section: Continued Development Of External Antenna Rf Hion Sourcementioning

confidence: 99%

“…The beam output from the RFQ is continuously monitored with a beam current monitor toroid (BCM). Besides the Hinjector on the SNS accelerator system, we also operate two similar Hinjectors on test facilities for ion source and LEBT development, and for new RFQ commissioning and various beam studies [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

H^- ion source operational performance and latest development at the Spallation Neutron Source

Han

Stöckli

Welton

et al. 2022

J. Phys.: Conf. Ser.

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The U.S. Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is the world’s most powerful accelerator-driven pulsed neutron source. An H- injector feeds the accelerator with high current (>50 mA), time structured (1ms, 60 Hz) H- beam. The injector consists of an RF-driven, Cs-enhanced H- ion source and an electrostatic low energy beam transport section. In the recent three run cycles, an H- ion source operated ∼4 months for each run with excellent availability near 99.9%. The presently ongoing run is also on track to finish another ∼4 months run with similar high availability. Lately, we have tested a solid-state RF system for the ion source to replace the existing vacuum-tube type RF amplifier for the sake of improving the ease of operation and maintenance. Progress has also been made on the continued development of an external antenna RF H- ion source with a focus on improvement to its plasma ignition scheme.

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Diagnostics of RF coupling in H− ion sources as a tool for optimizing source design and operational parameters

Briefi

Zielke

Rauner

et al. 2022

Review of Scientific Instruments

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Radio frequency (RF) driven H− ion sources are operated at very high power levels of up 100 kW in order to achieve the desired performance. For the experimental setup, these are demanding conditions possibly limiting the source reliability. Therefore, assessing the optimization potential in terms of RF power losses and the RF power transfer efficiency η to the plasma has moved to the focus of both experimental and numerical modeling investigations at particle accelerator and neutral beam heating sources for fusion plasmas. It has been demonstrated that, e.g., at typical neutral beam injection ion source setups, about half of the RF power provided by the generator is lost in the RF coil and the Faraday shield due to Joule heating or via eddy currents. In a best practice approach, it is exemplarily demonstrated at the ITER RF prototype ion source how experimental evaluation accompanied by numerical modeling of the ion source can be used to improve η. Individual optimization measures regarding the Faraday shield, the RF coil, the discharge geometry, the RF driving frequency, and the application of ferrites are discussed, which could reduce the losses by a factor of two. The provided examples are intended as exemplary guidelines, which can be applied at other setups in order to achieve with low-risk effort an optimized ion source design in terms of reduced losses and hence increased reliability.

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H− ion source research and development at the Oak Ridge National Laboratory

Cited by 10 publications

References 15 publications

Negative hydrogen ion sources for particle accelerators: Sustainability issues and recent improvements in long-term operations

Negative hydrogen ion sources for particle accelerators: Sustainability issues and recent improvements in long-term operations

H^- ion source operational performance and latest development at the Spallation Neutron Source

Diagnostics of RF coupling in H− ion sources as a tool for optimizing source design and operational parameters

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H− ion source research and development at the Oak Ridge National Laboratory

Cited by 10 publications

References 15 publications

Negative hydrogen ion sources for particle accelerators: Sustainability issues and recent improvements in long-term operations

Negative hydrogen ion sources for particle accelerators: Sustainability issues and recent improvements in long-term operations

H- ion source operational performance and latest development at the Spallation Neutron Source

Diagnostics of RF coupling in H− ion sources as a tool for optimizing source design and operational parameters

Contact Info

Product

Resources

About

H^- ion source operational performance and latest development at the Spallation Neutron Source