Wake fields in a mm-wave linac

Zimmermann, Frank; Whittum, D.; Ng, C.; Hill, Marc E

doi:10.1063/1.58904

Cited by 6 publications

(5 citation statements)

References 7 publications

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“…Thus to avoid compounding those features of beam dynamics that are hidden from the instrumentation, the linac should not amplify incoming beam offsets. The scaling for amplification in a W-Band linac is given in (80), where end-to-end quads of equal gradient and thickness l are considered. Quadrupole gradient is limited by achievable pole-tip field and pole aperture.…”

Section: Advanced Structure Conceptsmentioning

confidence: 99%

Ultimate gradient in solid-state accelerators

Whittum

1999

AIP Conference Proceedings

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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

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Section: Advanced Structure Conceptsmentioning

confidence: 99%

Ultimate gradient in solid-state accelerators

Whittum

1999

AIP Conference Proceedings

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“…Also Hill et al [38][39][40][41] tested both a single metallic W-band cavity and a dielectric linear accelerator excited with an electron beam. They studied the longitudinal and transverse wakefields in a 91 GHz dielectric coated accelerating structure [42]. Henke and Bruns [43][44][45][46] and Chou and Kroll at SLAC designed a W-band muffin-tin planar accelerator structure [47][48][49].…”

Section: Introductionmentioning

confidence: 99%

rf breakdown tests of mm-wave metallic accelerating structures

Forno

Dolgashev

Bowden

et al. 2016

Phys. Rev. Accel. Beams

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We are exploring the physics and frequency-scaling of vacuum rf breakdowns at sub-THz frequencies. We present the experimental results of rf tests performed in metallic mm-wave accelerating structures. These experiments were carried out at the facility for advanced accelerator experimental tests (FACET) at the SLAC National Accelerator Laboratory. The rf fields were excited by the FACET ultrarelativistic electron beam. We compared the performances of metal structures made with copper and stainless steel. The rf frequency of the fundamental accelerating mode, propagating in the structures at the speed of light, varies from 115 to 140 GHz. The traveling wave structures are 0.1 m long and composed of 125 coupled cavities each. We determined the peak electric field and pulse length where the structures were not damaged by rf breakdowns. We calculated the electric and magnetic field correlated with the rf breakdowns using the FACET bunch parameters. The wakefields were calculated by a frequency domain method using periodic eigensolutions. Such a method takes into account wall losses and is applicable to a large variety of geometries. The maximum achieved accelerating gradient is 0.3 GV=m with a peak surface electric field of 1.5 GV=m and a pulse length of about 2.4 ns.

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“…Also, Hill et al [45][46][47][48] tested both a single metallic W-band cavity and a dielectric linear accelerator excited with an electron beam. They studied the longitudinal and transverse wakefields in a 91 GHz dielectric-coated accelerating structure [49]. Henke and Bruns [50][51][52][53] and Chou and Kroll at SLAC designed a W-band muffin-tin planar accelerator structure [54][55][56].…”

Section: Introductionmentioning

confidence: 99%

rf breakdown measurements in electron beam driven 200 GHz copper and copper-silver accelerating structures

Forno

Dolgashev

Bowden

et al. 2016

Phys. Rev. Accel. Beams

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This paper explores the physics of vacuum rf breakdowns in subterahertz high-gradient traveling-wave accelerating structures. We present the experimental results of rf tests of 200 GHz metallic accelerating structures, made of copper and copper-silver. These experiments were carried out at the Facility for Advanced Accelerator Experimental Tests (FACET) at the SLAC National Accelerator Laboratory. The rf fields were excited by the FACET ultrarelativistic electron beam. The traveling-wave structure is an open geometry, 10 cm long, composed of two halves separated by a gap. The rf frequency of the fundamental accelerating mode depends on the gap size and can be changed from 160 to 235 GHz. When the beam travels off axis, a deflecting field is induced in addition to the longitudinal field. We measure the deflecting forces by observing the displacement of the electron bunch and use this measurement to verify the expected accelerating gradient. Furthermore, we present the first quantitative measurement of rf breakdown rates in 200 GHz metallic accelerating structures. The breakdown rate of the copper structure is 10 −2 per pulse, with a peak surface electric field of 500 MV=m and a rf pulse length of 0.3 ns, which at a relatively large gap of 1.5 mm, or one wavelength, corresponds to an accelerating gradient of 56 MV=m. For the same breakdown rate, the copper-silver structure has a peak electric field of 320 MV=m at a pulse length of 0.5 ns. For a gap of 1.1 mm, or 0.74 wavelengths, this corresponds to an accelerating gradient of 50 MV=m.

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Wake fields in a mm-wave linac

Cited by 6 publications

References 7 publications

Ultimate gradient in solid-state accelerators

Ultimate gradient in solid-state accelerators

rf breakdown tests of mm-wave metallic accelerating structures

rf breakdown measurements in electron beam driven 200 GHz copper and copper-silver accelerating structures

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