RF systems for the KEK B-Factory

Akai, K.; Akasaka, N.; Ebihara, K.; Ezura, E.; Furuya, T.; Hara, K.; Hosoyama, K.; Isagawa, S.; Kabe, A.; Kageyama, T.; Kojima, Yuuji; Mitsunobu, S.; Mizuno, Hajime; Morita, Y.; Nakai, H.; Nakanishi, Hiroshi; Ono, Masaaki; Sakai, Hiroshi; Suetake, M.; Tajima, T.; Takeuchi, Y.; Yamazaki, Yoichi; Yoshimoto, S.

doi:10.1016/s0168-9002(02)01773-4

Cited by 28 publications

(10 citation statements)

References 4 publications

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“…This is nevertheless insufficient for the levels expected in Z-pole operation. Moreover, the warm beam line sections between cryostats increase the overall cryogenic heat load and take up significant amounts of space; taking as an example the KEKB 509 MHz single-cell cavity module with ferrite absorbers [10], the overall length is 3.7 m, which for 1468 cavities in each of the two beam pipes would lead to extremely long RF sections of over 10 km total length. An extensive research and development program will be required to refine the cavity and HOM damping system design.…”

Section: Pos(eps-hep2015)525mentioning

confidence: 99%

The RF system for FCC-ee

Butterworth¹,

Calaga²,

Brunner³

et al. 2016

Proceedings of the European Physical Society Conference on High Energy Physics — PoS(EPS-HEP2015)

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The FCC-ee is a high-luminosity, high-precision e + e − circular collider, envisioned in a new 80-100 km tunnel in the Geneva area. It is envisaged to operate the collider with centre of mass energies ranging from 90 GeV for Z production to 350 GeV at the tt threshold. With a constant power budget for synchrotron radiation, the FCC-ee RF system must meet the requirements for both the highest possible accelerating voltage and very high beam currents with the same machine, albeit possibly at different stages. Beam-induced higher order mode power will be a major issue for running at the Z pole, and will have a strong impact on the RF system design. Iterations are ongoing on RF scenarios and staging, choice of cavities and cryomodule layout, RF frequency and cryogenic temperature.

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Section: Pos(eps-hep2015)525mentioning

confidence: 99%

The RF system for FCC-ee

Butterworth¹,

Calaga²,

Brunner³

et al. 2016

Proceedings of the European Physical Society Conference on High Energy Physics — PoS(EPS-HEP2015)

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“…Radio-frequency (rf) input couplers (couplers) are one of the most important components in high-power rf systems. In the normal-conducting accelerating cavity system ARES 1 [1][2][3] for the KEK B-factory (KEKB) [3][4][5][6][7][8][9][10][11][12], coaxial-line couplers are used to feed high power from klystrons into accelerating cavities with heavy beam loading. Figure 1 shows a schematic diagram of the coupler for the ARES, where the coaxial line, which is made of oxygen-free copper and has an outer (inner) radius of the inner (outer) conductor of 16.7 mm (38.5 mm), has a loop at its end for coupling to the magnetic field of the TE 013 mode in the energy-storage cavity of the three-cavity system of the ARES [13].…”

Section: Introductionmentioning

confidence: 99%

Multipactoring suppression by fine grooving of conductor surfaces of coaxial-line input couplers for high beam current storage rings

Abe

Kageyama

Sakai

et al. 2010

Phys. Rev. ST Accel. Beams

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Input couplers for radio-frequency accelerating cavities with heavy beam loading undergo many multipactoring zones due to the wide range of input powers. Furthermore, regular coaxial lines have more multipactoring than rectangular waveguides because of more uniformity of the electromagnetic field. Grooving conductor surfaces of coaxial lines is expected to be a promising method for suppressing multipactoring under any conditions with heavy beam loading. In this paper, we present a method for designing practical fine grooves on conductor surfaces of coaxial lines to suppress multipactoring, based on multipactoring zone maps, and demonstrate the suppressive power both in high-power tests and accelerator operations.

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“…Two approaches to reducing the instability growth rates induced by the fundamental impedance include impedance minimization [3] and active feedback [4]. Impedance minimization techniques are very similar to the methods of reducing the synchronous phase transient that were described earlier.…”

Section: Longitudinal Coupled-bunch Instabilitiesmentioning

confidence: 99%

“…Significant attention to the beam loading was already paid in the design of the existing B-factories with the two machines selecting radically different solutions [3,4]. Projected beam current increases for the super B-factories amplify the significance of the beam loading making it the defining element in the design of the RF system.…”

Section: Introductionmentioning

confidence: 99%

Beam-Loading Compensation for Super B-Factories

Teytelman

Proceedings of the 2005 Particle Accelerator Conference

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Super B-factory designs under consideration expect to reach luminosities in the ½¼ ¿ -½¼ ¿ range. The dramatic luminosity increase relative to the existing B-factories is achieved, in part, by raising the beam currents stored in the electron and positron rings. For such machines to succeed it is necessary to consider in the RF system design not only the gap voltage and beam power, but also the beam loading effects. The main effects are the synchronous phase transients due to the uneven ring filling patterns and the longitudinal coupled-bunch instabilities driven by the fundamental impedance of the RF cavities. A systematic approach to predicting such effects and for optimizing the RF system design will be presented. Existing as well as promising new techniques for reducing the effects of heavy beam loading will be described and illustrated with examples from the PEP-II and the KEKB.

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RF systems for the KEK B-Factory

Cited by 28 publications

References 4 publications

The RF system for FCC-ee

The RF system for FCC-ee

Multipactoring suppression by fine grooving of conductor surfaces of coaxial-line input couplers for high beam current storage rings

Beam-Loading Compensation for Super B-Factories

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