Recent studies on photoelectron and secondary electron yields of TiN and NEG coatings using the KEKB positron ring

Suetsugu, Y.; Kanazawa, Kenichi; Shibata, K.; Hisamatsu, Hiromi

doi:10.1016/j.nima.2007.06.015

Cited by 19 publications

(6 citation statements)

References 33 publications

(53 reference statements)

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“…This is consistent with values measured elsewhere [6]. All of the coated chambers (aC, TiN, DLC, and NEG) had much lower values, corresponding in all cases to a peak SEY ≤ 0.9, and also consistent with direct measurements [4,14,15,35]. The fitted values for TiN and DLC in particular are very low, implying a peak SEY on the order of 0.7.…”

Section: Resultssupporting

confidence: 88%

Measurement and modeling of electron cloud in a field free environment using retarding field analyzers

Calvey

Dugan

Hartung

et al. 2014

Phys. Rev. ST Accel. Beams

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As part of the CESRTA program at Cornell, diagnostic devices to measure and quantify the electron cloud effect have been installed throughout the CESR ring. One such device is the retarding field analyzer, which provides information on the local electron cloud density and energy distribution. In a magnetic field free environment, retarding field analyzer measurements can be directly compared with simulation to study the growth and dynamics of the cloud on a quantitative level. In particular, the photoemission and secondary emission characteristics of the instrumented chambers can be determined simultaneously.

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Section: Resultssupporting

confidence: 88%

Measurement and modeling of electron cloud in a field free environment using retarding field analyzers

Calvey

Dugan

Hartung

et al. 2014

Phys. Rev. ST Accel. Beams

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“…This simple reasoning shows how important it is to experimentally determine the photon reflectivity (R) of accelerator walls and its PY. [16][17][18][19][20][21][22][23][24] If SR is not energetic enough to create photoelectrons, as in case of LHC at injection energy, residual gas ionization by beam particles becomes a possible source of primary electrons. The number of electrons produced per unit length by a bunch of N b particles can be expressed as:…”

Section: Primary Electronsmentioning

confidence: 99%

Electron cloud in accelerators

Cimino

Demma

2014

Int. J. Mod. Phys. A

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Low energy electrons in accelerators are known to interact with the circulating beam, giving rise to the formation of a so-called e − cloud. Such e − cloud may induce detrimental effects on the accelerated beam quality and stability. Those effects have been observed in most accelerators of positively charged particles. A longstanding effort has been so far devoted to understand in detail the physical origin of such e − cloud, its build-up and its interaction with the circulating beam. We will first describe the origin and the basic features causing e − cloud formation in accelerators, then we review some of the theoretical work produced to simulate and analyze such phenomenon. In selected cases, theoretical expectations and experimental observations will be compared, to address the importance of benchmarking codes versus observations to reach the required predictive capability. To this scope, codes need realistic input parameters which correctly describe material and surface properties at the basis of such e − cloud formation and build-up. The experimental efforts, performed worldwide in many surface and material science laboratories, to measure such essential parameters will then be presented and critically reviewed. Finally, we will describe some of the e − cloud mitigation strategies adopted so far and draw some conclusions.

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“…24 Circular copper chambers with NEG or TiN coatings were installed in the arc and straight sections of the KEKB LER for tests, and the number of electrons around the positron beams was measured and compared. 31 In the experiment, the electron numbers in the beam pipes with the TiN coating and the NEG coating were approximately 1/3 and 2/3 of that for a copper chamber without any coating in the straight section where little SR was irradiated and the effect of photoelectrons was small. The TiN coating showed a similar result on an aluminum test chamber.…”

Section: Countermeasures For the Electron Cloud Effectmentioning

confidence: 86%

Design and construction of the SuperKEKB vacuum system

Suetsugu

Kanazawa

Shibata

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Development of planar x-ray source using gated carbon nanotube emitter J. Vac. Sci. Technol. B 31, 02B110 (2013) Tungstate formation in a model scandate thermionic cathode J. Vac. Sci. Technol. B 31, 011210 (2013) Influence of gun design on Coulomb interactions in a field emission gun J. Vac. Sci. Technol. B 29, 06F605 (2011) Model scandate cathodes investigated by thermionic-emission microscopyA two-ring electron-positron collider with asymmetric energies-called the SuperKEKB-has been designed by the High Energy Accelerator Research Organization (KEK) as an upgrade of the KEKB B-factory (KEKB), which completed 12 years of operation in 2010. It is anticipated that the SuperKEKB will reach a luminosity of 8 Â 10 35 cm À2 s À1 , which is approximately 40 times larger than that of the original KEKB. The upgrade of the vacuum system is a key factor that will allow the SuperKEKB to achieve unprecedented high performance. Most of the beam pipes, especially in the positron ring, are newly manufactured to manage the electron cloud effect, and to reduce beam impedance, which is essential to keep the low-emittance beam stable. Our design of the vacuum system implements recent technologies and draws on various experiences and studies during the operation of the original KEKB. The basic design is near completion, and manufacturing of beam pipes and the major vacuum components, such as bellows chambers, gate valves and supports, are in progress. The installation of these components will start in 2013 with the aim of commissioning the SuperKEKB in

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Recent studies on photoelectron and secondary electron yields of TiN and NEG coatings using the KEKB positron ring

Cited by 19 publications

References 33 publications

Measurement and modeling of electron cloud in a field free environment using retarding field analyzers

Measurement and modeling of electron cloud in a field free environment using retarding field analyzers

Electron cloud in accelerators

Design and construction of the SuperKEKB vacuum system

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