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

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.