Speaker
Description
In the High Luminosity Large Hadron Collider (HL-LHC) phase the instantaneous luminosity of proton–proton collisions will significantly increase, imposing more demanding operating conditions on detector systems, while maintaining the excellent physics performance of the experiments.
The upgrade of the TileCal laser calibration system for the HL-LHC phase of the ATLAS experiment is currently in the commissioning stage. A key innovation of the upgraded system is the introduction of an adjustable continuous light component, generated by a LED array and superimposed on the pulsed laser light. This approach allows the calibration of the almost 10000 TileCal photomultiplier tubes (PMTs) under controlled average anode current conditions, reproducing the environment expected during high-luminosity operation. To achieve stable and uniform mixing of the pulsed and continuous light components, a four-port integrating sphere has been implemented in the optical distribution line.
This solution represents a scalable and robust calibration technology with potential applications in future calorimeter systems. The design, validation tests, and first commissioning results of the new optical line will be presented.