VELO with SMOG2 Impedance-based Heating Localization Analysis

In connection to the proposed upgrade (SMOG2) of the existing gas injection system for the LHCb experiment (SMOG), the potential heating due to induced longitudinal beam impedance of the VELO with the SMOG2 is investigated. The analysis looks at heating of the individual components of the object in the open position, especially potential heating of the SMOG2 cell. By means of the CST Eigenmode solver, the entire structure is simulated and the mode results are used for processing in a Python script. The Python script uses a BE-RF-BR script to generate a LIU-LHC beam spectrum. Within the Python script, two different ‘worst case scenario’ studies are performed assuming the LIU-LHC beam spectrum. One study looks at the heating caused by individual modes, with each mode shifted to hit the beam resonance lines. The other study observes total heating due to all the mode for a range up to 900 MHz, with the modes shifted in unison, thereby hitting beam resonance lines. Both methods provide the opportunity to distinguish the heat deposited in the individual components of the VELO.