Heat load profile estimates on LHC beam screens by thermal transient analysis

B Bradu,C Garion,K Brodzinski,L Tavian,D Delikaris

doi:10.1088/1757-899x/502/1/012116

B Bradu, C Garion + Show 3 more

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https://doi.org/10.1088/1757-899x/502/1/012116

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Abstract

The LHC beams are producing significant dynamic heat loads on the LHC cryogenic system. These heat loads are deposited on beam screens, where they must be properly extracted with dedicated cooling loops between 4.6 K and 20 K. Since 2015, unexpected beam-induced heat loads are observed in specific locations of the machine and their origin is still not completely understood. In order to improve our understanding on the heat load origin and on the spread between them on different areas of the accelerator, the thermal transients occurring after the beam dumps have been analyzed to reconstruct the heat load profiles of the beam screens. Following a description of this specific issue, the paper presents the methodology used for the measurements and estimates of the heat load profiles and its validation against some experimental data and dynamic simulations.

Highlights

IntroductionSince 2015, the LHC (Large Hadron Collider) runs with a proton bunch spacing of 25 ns generating important heat loads on the cryogenic beam screens located inside the beam pipes
In order to improve our understanding on the heat load origin and on the spread between them on different areas of the accelerator, the thermal transients occurring after the beam dumps have been analyzed to reconstruct the heat load profiles of the beam screens
Since 2015, the LHC (Large Hadron Collider) runs with a proton bunch spacing of 25 ns generating important heat loads on the cryogenic beam screens located inside the beam pipes

Summary

Introduction

Since 2015, the LHC (Large Hadron Collider) runs with a proton bunch spacing of 25 ns generating important heat loads on the cryogenic beam screens located inside the beam pipes. These beam screens are maintained between 4.6 K and 20 K during the beam operation using supercritical helium [1]. In order to identify the possible root cause of this phenomenon and to mitigate it, a beam-induced heat load task force composed by about 20 CERN members representing the concerned fields of expertise has been setup. In the framework of this task force, it was asked to locate as precisely as possible these abnormal heat loads along the beam screens

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Conclusion