PHOTOELECTRON YIELD AND PHOTON REFLECTIVITY FROM CANDIDATE LHC VACUUM CHAMBER MATERIALS WITH IMPLICATIONS TO THE VACUUM CHAMBER DESIGN
PHOTOELECTRON YIELD AND PHOTON REFLECTIVITY FROM CANDIDATE LHC VACUUM CHAMBER MATERIALS WITH IMPLICATIONS TO THE VACUUM CHAMBER DESIGN
复制标题
大型强子对撞机候选真空室材料的光电子产率和光子反射率对真空室设计的影响
DOI：
--
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
O. Gröbner
中科院分区：
文献类型：
--
作者：
V. Baglin;I. Collins;O. Gröbner
在欧洲核子研究中心（CERN）正电子蓄能器（EPA）环上的专用束流线上，对候选LHC真空室材料在掠入射（11mrad）下的光电子产率和光子反射率进行了研究。这些测量为更好地理解大型强子对撞机中预期的电子云现象提供了现实的输入。测量采用同步辐射，临界光子能量分别为194 eV和45 eV；后者相当于大型强子对撞机的d符号能量为7 TeV。测试材料主要是铜，i)通过共层或电镀在不锈钢上，或ii)通过特殊加工制备的大块铜。研究的关键参数是表面粗糙度对掠入射光子的反射率和光电子产率的影响，以及磁场方向对正常入射光子产率的影响。讨论了研究结果对电子云现象的影响，以及对大型强子对撞机真空室设计的影响。
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 d sign 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 i cidence, 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, nd thus the LHC vacuum chamber design, is discussed.