Main improvements of LHC Cryogenics Operation during Run 2 (2015-2018)

Cryogenic Engineering Conference 2017

材料科学;物理学

Delprat, L.^1 ; Bradu, B.^1 ; Brodzinski, K.^1 ; Ferlin, G.^1 ; Hafi, K.^1 ; Herblin, L.^1 ; Rogez, E.^1 ; Suraci, A.^1

CERN, Technology Department, Cryogenics Group, Geneva 23

1211, Switzerland^1

关键词: Consolidation programs;    Cryogenic system;    Dynamic behaviours;    Electrical distribution;    Operation temperature;    Operational periods;    Operational scenario;    Preventive and corrective maintenance;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/278/1/012098/pdf
DOI  :  10.1088/1757-899X/278/1/012098

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

After the successful Run 1 (2010-2012), the LHC entered its first Long Shutdown period (LS1, 2013-2014). During LS1 the LHC cryogenic system went under a complete maintenance and consolidation program. The LHC resumed operation in 2015 with an increased beam energy from 4 TeV to 6.5 TeV. Prior to the new physics Run 2 (2015-2018), the LHC was progressively cooled down from ambient to the 1.9 K operation temperature. The LHC has resumed operation with beams in April 2015. Operational margins on the cryogenic capacity were reduced compared to Run 1, mainly due to the observed higher than expected electron-cloud heat load coming from increased beam energy and intensity. Maintaining and improving the cryogenic availability level required the implementation of a series of actions in order to deal with the observed heat loads. This paper describes the results from the process optimization and update of the control system, thus allowing the adjustment of the non-isothermal heat load at 4.5 - 20 K and the optimized dynamic behaviour of the cryogenic system versus the electron-cloud thermal load. Effects from the new regulation settings applied for operation on the electrical distribution feed-boxes and inner triplets will be discussed. The efficiency of the preventive and corrective maintenance, as well as the benefits and issues of the present cryogenic system configuration for Run 2 operational scenario will be described. Finally, the overall availability results and helium management of the LHC cryogenic system during the 2015-2016 operational period will be presented.