RF breakdown studies in X-band klystron cavities

Xu, X.; Callin, R.S.; Fowkes, W.R.; Menegat, A.; Scheitrum, G.; Whittum, D.

doi:10.1109/pac.1997.753103

Cited by 4 publications

(6 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The result looked for in field-emission studies is a process that results in a structure working reliably at highpower. This process would include a recipe for fabrication, assembly, cleaning, processing, and any other steps bearing on the problems of material behavior subject to intense electromagnetic fields (44,45). It is known that cleanliness, bakeout, highpressure water-rinse, coatings, and sundry habits are helpful, but at present there is no generally-acclaimed recipe for normal conducting linacs (16).…”

Section: Problems Of High-gradientmentioning

confidence: 99%

“…One may surmise that this pulse-length dependence also favors higher frequencies, where natural structure fill-times are shorter. It is known that breakdown thresholds are lower in klystron output cavities (45), and this invites speculation about the influence of ionizing radiation. In sum, one is inclined to view field-emission, trapping and breakdown as parts of one problem: an uncontrolled free-electron population.…”

Section: Problems Of High-gradientmentioning

confidence: 99%

“…Fabrication, high-power studies at X-Band, and short-pulse field emission studies are being pursued. Application of composite structures promises other benefits at high-field (44,45).…”

Section: Advanced Structure Conceptsmentioning

confidence: 99%

See 2 more Smart Citations

Ultimate gradient in solid-state accelerators

Whittum

1999

AIP Conference Proceedings

View full text Add to dashboard Cite

We recall the motivation for research in high-gradient acceleration and the problems posed by a compact collider. We summarize the phenomena known to appear in operation of a solid-state structure with large fields, and research relevant to the question of the ultimate gradient. We take note of new concepts, and examine one in detail, a miniature particle accelerator based on an active millimeter-wave circuit and parallel particle beams. Baltimore, Maryland July 5-11, 1998 Work supported by U.S. Abstract. We recall the motivation for research in high-gradient acceleration and the problems posed by a compact collider. We summarize the phenomena known to appear in operation of a solid-state structure with large fields, and research relevant to the question of the ultimate gradient. We take note of new concepts, and examine one in detail, a miniature particle accelerator based on an active millimeter-wave circuit and parallel particle beams. Invited talk presented at the 8th Workshop on Advanced Accelerator Concepts

show abstract

Section: Problems Of High-gradientmentioning

confidence: 99%

Section: Problems Of High-gradientmentioning

confidence: 99%

See 1 more Smart Citation

Ultimate gradient in solid-state accelerators

Whittum

1999

AIP Conference Proceedings

View full text Add to dashboard Cite

show abstract

“…Thus when the cavities are in phase, they should oscillate as they would if there were no iris. This implies the coupling 26) and, from symmetry, sin ;…”

Section: Fmentioning

confidence: 99%

“…Control of field emission is an ongoing research activity at present, concerning itself with surface finish, coatings and cleanliness. 26 At the same time, there is experimental evidence that field emission is inhibited on short, nanosecond time-scales, 27 and this suggests that to reach high gradient, one could consider structures with natural fill times on the nanosecond scale. This implies a short rf wavelength, on the order of millimeters.…”

Section: Epiloguementioning

confidence: 99%

Introduction to Electrodynamics for Microwave Linear Accelerators

Whittum¹

1999

Frontiers of Accelerator Technology

View full text Add to dashboard Cite

This collection of notes and exercises is intended as a workbook to introduce the principles of microwave linear accelerators, starting with the underlying foundation in electrodynamics. We review Maxwell's equations, the Lorentz force law, and the behavior of fields near a conducting boundary. We go on to develop the principles of microwave electronics, including waveguide modes, circuit equivalence, shunt admittance of an iris, and voltage standing-wave ratio. We construct an elementary example of a waveguide coupled to a cavity, and examine its behavior during transient filling of the cavity, and in steady-state. We go on to examine a periodic line. We then turn to examine the problem of acceleration in detail, studying first the properties of a single cavity-waveguide-beam system and developing the notions of wall Q, external Q, [R/Q], shunt impedance, and transformer ratio. We examine the behavior of such a system on and off resonance, on the bench, and under conditions of transient and steady-state beam-loading. This work provides the foundation for the commonly employed circuit equivalents and the basic scalings for such systems. Following this we examine the coupling of two cavities, powered by a single feed, and go on to consider structures constructed from multiple coupled cavities. The basic scalings for constant impedance and constant gradient travelling-wave structures are set down, including features of steady-state beamloading, and the coupled-circuit model. Effects of uniform and random detuning are derived. These notes conclude with a brief outline of some problems of current interest in accelerator research.

show abstract