ATLAS Tile Calorimeter Phase-II Upgrade: Electronics Certification with the Portable Readout Module “PROMETEO”

The High-Luminosity LHC (HL-LHC) will extend the physics reach of the ATLAS experiment, bringing new opportunities for discovery and for measuring the properties of particles. To achieve this, the HL-LHC requires a complete upgrade of the ATLAS detector, including its Tile Calorimeter (TileCal). TileCal is a sampling hadronic calorimeter covering the central region of the ATLAS experiment in a pseudorapidity range of |η| < 1.7. It consists of thin steel plates and about 460000 scintillating tiles configured into 5182 cells, each viewed by two photomultipliers (PMTs). The Phase-II upgrade of TileCal will include a complete replacement of its on- and off-detector electronics, as well as 10% of the PMTs in the most exposed regions. PMT signals from every TileCal channel will be digitized and sent directly to the back-end electronics, where the signals are reconstructed, stored, and sent to the first level of trigger at a rate of 40 MHz. This will provide better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. This large-scale replacement presents a considerable challenge in terms of testing and certification of the new electronics. To address this, the Portable ReadOut ModulE for Tile Electronics (PROMETEO) system has been developed as a portable tool for testing and certifying both the on- and off-detector electronics. While PROMETEO was originally designed primarily for electronics certification, research and development efforts have revealed a clear need for fast and precise optical testing of both the current and new PMTs. As a result, future developments of PROMETEO will incorporate optical measurement capabilities, including the ability to measure relative quantum efficiency and dark current for all the PMTs. This article presents the current status of the TileCal Phase-II upgrade project, along with expected performance characteristics. In addition, the PROMETEO system for testing and certifying of new electronics and its future enhancements are discussed.