Dynamic pressure in the LHC: influence of ions induced by ionization of residual gas by both the proton beam and the electron cloud
Dynamic pressure in the LHC: influence of ions induced by ionization of residual gas by both the proton beam and the electron cloud
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DOI：
10.1088/1742-6596/1350/1/012171
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发表时间：
2019-05
期刊：
影响因子：
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通讯作者：
S. Bilgen;C. Bruni;B. Mercier;G. Sattonnay;V. Baglin
中科院分区：
文献类型：
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作者：
S. Bilgen;C. Bruni;B. Mercier;G. Sattonnay;V. Baglin
对于未来的HL-LHC或FCC研究，了解束流与真空室的相互作用对于提供缓解电子、光子和离子分子脱附引起的压力上升的解决方案是至关重要的。在大型强子对撞机真空室中循环的质子束使残余气体电离，产生电子和正离子。在大型强子对撞机第二次运行期间，在大型强子对撞机真空试验区进行了现场测量，以监测动态压力，并收集由于电子云和离子与真空室壁相互作用产生的电信号。对铜电极记录的电信号进行了实验测量，并与考虑了铜的二次电子产额和电子能量分布的计算结果进行了比较。最后，铜电极似乎没有完全调节好，可以估计出离子电流。
For the future HL-LHC or FCC study, the understanding of the beam interactions with the vacuum chamber is fundamental to provide solutions to mitigate the pressure rises induced by electronic, photonic and ionic molecular desorption. The proton beam circulating in the LHC vacuum chamber ionizes the residual gas producing electrons as well as positive ions. In-situ measurements were carried out, on the LHC Vacuum Pilot Sector during the LHC RUN II, to monitor the dynamic pressure, and to collect the electrical signals due to the electron cloud and to the ions interacting with the vacuum chamber walls. Experimental measurements of electrical signals recorded by copper electrodes were compared to calculations taking into account both the Secondary Electron Yield of copper and electron energy distribution. Finally, it seems that copper electrodes were not fully conditioned and an ion current could be estimated.