Performance experience with the CEBAF SRF cavities

Reece, Charles; Benesch, J.; Drury, M.; Hovater, C.; Mammosser, J.; Powers, T.; Preble, J.

doi:10.1109/pac.1995.505269

Cited by 12 publications

(6 citation statements)

References 7 publications

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“…Because of the very high priority for the new laboratory to not disappoint the nuclear physics users, the baseline project performance specifications were set deliberately quite conservative: accelerating gradient of 5 MV/m and Q 0 of only 2.4×10 9 . Just what the actual installed performance capacity turned out to be was of keen interest and was reported to the Particle Accelerator Conference in 1995 [51], summarized here.…”

Section: Cryomodule Commissioningmentioning

confidence: 96%

Continuous wave superconducting radio frequency electron linac for nuclear physics research

Reece

2016

Phys. Rev. Accel. Beams

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CEBAF, the Continuous Electron Beam Accelerator Facility, has been actively serving the nuclear physics research community as a unique forefront international resource since 1995. This CW electron linear accelerator (linac) at the U.S. Department of Energy's Thomas Jefferson National AcceleratorFacility (Jefferson Lab) has continued to evolve as a precision tool for discerning the structure and dynamics within nuclei. Superconducting RF (SRF) technology has been the essential foundation for CEBAF, first as a 4 GeV machine, then 6 GeV, and currently capable of 12 GeV. We review the development, implementation, and performance of SRF systems for CEBAF from its early beginnings to the commissioning of the 12 GeV era.

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Section: Cryomodule Commissioningmentioning

confidence: 96%

Continuous wave superconducting radio frequency electron linac for nuclear physics research

Reece

2016

Phys. Rev. Accel. Beams

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“…This is usually done by means of commercially available carbon brushes rotating over a copper ring. If an external water cooling shower is used [54], then the recirculating acid need not be the primary means of removing heat from the system, and the flow of recirculating electrolyte can be relatively slow, such as 1 l min -1 per square meter of cavity surface area. If the acid is cooled in an external container, then flow rates are roughly one order higher.…”

Section: Horizontal Electropolishing For Elliptical Cell Cavitiesmentioning

confidence: 99%

Surface processing for bulk niobium superconducting radio frequency cavities

Kelly

Reid

2017

Supercond. Sci. Technol.

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The majority of niobium cavities for superconducting particle accelerators continue to be fabricated from thin-walled (2–4 mm) polycrystalline niobium sheet and, as a final step, require material removal from the radio frequency (RF) surface in order to achieve performance needed for use as practical accelerator devices. More recently bulk niobium in the form of, single- or large-grain slices cut from an ingot has become a viable alternative for some cavity types. In both cases the so-called damaged layer must be chemically etched or electrochemically polished away. The methods for doing this date back at least four decades, however, vigorous empirical studies on real cavities and more fundamental studies on niobium samples at laboratories worldwide have led to seemingly modest improvements that, when taken together, constitute a substantial advance in the reproducibility for surface processing techniques and overall cavity performance. This article reviews the development of niobium cavity surface processing, and summarizes results of recent studies. We place some emphasis on practical details for real cavity processing systems which are difficult to find in the literature but are, nonetheless, crucial for achieving the good and reproducible cavity performance. New approaches for bulk niobium surface treatment which aim to reduce cost or increase performance, including alternate chemical recipes, barrel polishing and ‘nitrogen doping’ of the RF surface, continue to be pursued and are closely linked to the requirements for surface processing.

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“…Having individual controls allows each to be run at its optimal level with precise control over the phase and gradient. The cavity performance has considerably exceeded the design goal of 5 MeVlm [7]. The entire RF system can be controlled and monitored from a single control system screen [SI that provides the operators with the ability to quickly locate problems.…”

Section: Portions Of This Document May Be Illegiblementioning

confidence: 99%

Jefferson Lab, a status report

Dunham¹

1996

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Thomas Jefferson National Accelerator Facility (Jefferson Lab; formerly known as CEBAF), operates a 4 GeV, 200 pA continuous wave (CW) electron accelerator that re-circulates the beam five times through two superconducting 400 MeV linacs. Electrons can be extracted from any of the five recirculation passes and beam can be simultaneously delivered to the three experimental halls.As the commissioning stage nears completion, the accelerator is becoming a hlly operational machine. Experiments in Hall C have been underway since November 1995 with beam powers of over 300 kW at various energies. Hall A has received beam for spectrometer commissioning, while Hall B is expected to receive ik first beam in the fall of 1996. Accelerator availability of greater than 70% during physics runs and excellent beam quality have contributed to making Jefferson Lab a world class laboratory for accelerator-based electromagnetic nuclear physics. With the high performance of the superconducting RY cavities, machine upgrades to 6 GeV, and eventually 8 to 10 GeV are now in the planning stages. Operational and commissioning details concerning all aspects of the machine will be discussed.

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Performance experience with the CEBAF SRF cavities

Cited by 12 publications

References 7 publications

Continuous wave superconducting radio frequency electron linac for nuclear physics research

Continuous wave superconducting radio frequency electron linac for nuclear physics research

Surface processing for bulk niobium superconducting radio frequency cavities

Jefferson Lab, a status report

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