Photoelectron Yield and Photon Reflectivity from Candidate LHC Vacuum Chamber with Implications to the Vacuum Chamber Design
Photoelectron Yield and Photon Reflectivity from Candidate LHC Vacuum Chamber with Implications to the Vacuum Chamber Design
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候选大型强子对撞机真空室的光电子产率和光子反射率对真空室设计的影响
DOI：
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发表时间：
1998
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影响因子：
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通讯作者：
O. Gröbner
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作者：
V. Baglin;I. Collins;O. Gröbner
在欧洲核子研究中心（CERN）电子正电子累积器（EPA）环上的专用束线上，对LHC真空室候选材料在掠入射（11 mrad）下的光电子产额和光子反射率进行了研究。这些测量结果为更好地理解LHC中预期的电子云现象提供了现实的输入。测量是使用同步辐射与临界光子能量为194 eV和45 eV;后者对应于在7 TeV的设计能量的大型强子对撞机。测试材料主要是铜，i）通过共层压或通过电镀涂覆到不锈钢上，或ii）通过特殊机械加工制备的块状铜。探索的关键参数是表面粗糙度的反射率和掠入射光子的光电子产额的影响，和磁场方向的影响，在正常的光子入射测量的产量。电子云现象的结果的影响，从而LHC真空室的设计，进行了讨论。
Studies of the photoelectron yield and photon reflectivity at grazing incidence (11 mrad) from candidate LHC vacuum chamber materials have been made on a dedicated beam line on the Electron–Positron Accumulator (EPA) ring at CERN. These measurements provide realistic input toward a better understanding of the electron cloud phenomena expected in the LHC. The measurements were made using synchrotron radiation with critical photon energies of 194 eV and 45 eV; the latter corresponding to that of the LHC at the design energy of 7 TeV. The test materials are mainly copper, either, i) coated by co-lamination or by electroplating onto stainless steel, or ii) bulk copper prepared by special machining. The key parameters explored were the effect of surface roughness on the reflectivity and the photoelectron yield at grazing photon incidence, and the effect of magnetic field direction on the yields measured at normal photon incidence. The implications of the results on the electron cloud phenomena, and thus the LHC vacuum chamber design, is discussed.