Photodesorption from stainless steel, aluminum alloy and oxygen free copper test chambers

Ueda, Shinjiro; Matsumoto, Manabu; Kobari, Toshiaki; Ikeguchi, Takashi; Kobayashi, Masanori; Hori, Yoichiro

doi:10.1016/0042-207x(90)94134-c

Cited by 22 publications

(3 citation statements)

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“…5-19 yields only a rough estimate of the actual dynamic gas load but one that is nonetheless useful in setting the scale of the engineering task, as well as in choosing the chamber material. [Grobner et al, 1983;Foerster et al, 1990;Ueda et al, 1990;Mathewson et al 1990] for well-exposed samples of aluminum, stainless steel, and oxygen-free, high-conductivity copper indicate minimum values of rj ranging from less than 2 x 10"" 6 for copper and stainless steel up to 2 x 10~5 for aluminum. Although the gas-scattering lifetimes in storage rings with lower critical photon energies than the B Factory suggest that aluminum chambers may eventually develop an effective fj = 10 -6 , we believe a more reliable design procedure is to adopt copper or stainless steel as the chamber material, despite their higher cost per kilogram.…”

Section: • Photon Energymentioning

confidence: 99%

“…We plan an experimental validation program as an essential component of the engineering design process. The experimental setup will follow closely the procedures that have been described extensively in the literature [Foerster et al, 1990;Ueda et al, 1990;Grobner et al, 1983;Mathewson et al, 1990]. The primary quantity to be measured will be the specific pressure rise AP/I, which is of most direct relevance to the engineering design of the B Factory vacuum system.…”

Section: Validation Testmentioning

confidence: 99%

“…This gas profile becomes a system specification for the vacuum engineer. Using the data of Ueda et al [1990], we have estimated that for copper with an initial desorption rate of 10 -3 molecules/photon, the sections of the chamber will reach 7J = 2x 10-d after a photon exposure of about 100 A hr. Based on the pumping scheme described in Section 5.2.4 (which provides 125 L/s/m distributed in the dipoles), the vacuum-conditioning scenario can be computed as a function of the initial photodesorption rate.…”

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An Asymmetric B-Factory Based on PEP

Oddone¹

1989

Ann NY Acad Sci

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OVERVIEWIT has become increasingly apparent in recent years that systems containing b quarks offer unique opportunities for studying the theoretical edifice of particle physics, the so-called "Standard Model." Although measurements with these b-quark systems offer a host of possibilities, the one that has riveted the attention of the particle physics community worldwide is the potential for understanding the origin of the phenomenon of CP violation-a small deviation in Nature's otherwise symmetric order that has been clearly observed but whose origins remain a mystery. The phenomenon of CP violation has cosmic consequences; in particular, it played a crucial role in the formation of our Universe. Thus, to understand it is one of the central goals in our quest to comprehend the orderly foundations of the natural world. The program of CP violation studies that we envision has great discovery potential; should the measurements disagree with predictions of the Standard Model, the observed pattern of CP violation will provide substantial and specific clues as to how the model should be extended.Capitalizing on recent advances in detector technology and newly acquired information on the properties of the b quark, it is r«jw widely accepted that a highluminosity, asymmetric e + e _ collider offers an ideal platform for an exhaustive study of CP violation. This fact was forcefully endorsed last year by HEPAP through the deliberations and recommendations of its subpanel on the U.S. High Energy Physics Research Program for the 1990s (the Sciulli panel, DOE/ER-0453P and the accompanying transmittal letter, April 1990). The thrust of HEPAP's recommendations was that the physics program of a B factory was compelling and that, given a technically sound proposal fof construction of a machine, funds for such a facility should be sought with high priority.While CP violation is the main motivation for the construction of a B factory, such a facility will also host a very exciting and broad-based program of bottom q,uark t charm quark, T, and two-photon physics. Important tests of the Standard Model are possible in this program and many gaps in our knowledge are sure to be filled in. Because the number and range of distinct topics is very large, an asymmetric B factory will be an ideal facility for the training of young physicists, and we envisage more than 200 Ph.D. theses during the lifetime of the program (conservatively estimated at 15 years). The specific machine implementation discussed heie has a single interaction region, though flexibility exists to expand this to two interaction regions, and therefore two detectors, should the user community consider this important enough to provide the extra funds. A OVERVIEW parasitic program of synchrotron radiation physics and nuclear physics would also be possible with additional funds.A very large international particle physics community is committed to physics studies at an asymmetric e + e-B factory. A group of physicists numbering more than 150 Ph.D.'s h?s been involved with the...

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Section: • Photon Energymentioning

confidence: 99%

Section: Validation Testmentioning

confidence: 99%

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