Speaker
Description
The Tile Calorimeter of the ATLAS experiment is being upgraded for the
high luminosity LHC. The powering scheme of the calorimeter modules has been updated to provide higher efficiency and redundancy. Switching power supplies used in each module are responsible for providing power to the front-end electronics. The original power supplies, which are currently being used in the detector, lack efficiency and radiation hardness for HL-LHC. Accordingly, many radiation tests have been performed and the design has been improved to provide higher efficiency and radiation tolerance.
Summary (500 words)
The switching power supply for the front-end electronics of the ATLAS Tile Calorimeter required some improvements in terms of efficiency, thermal management, start-up system, and radiation tolerance. The improvement of the efficiency and thermal management was essential due to limitations in the cooling system. The start-up circuitry had to be updated, as an improved control over powering of the modules of Tile Calorimeter and smoother performance at startup was required. Finally, all of the components had to be tested according to the updated radiation criteria of the calorimeter for the HL-LHC. For many components, several candidates were considered and tested to find the most radiation tolerant one. In some cases, a variation in radiation tolerance was observed between different batches of the same component, or different behaviors were seen during the tests performed using a mixed field irradiation for a single field one. Moreover, some components showed different behaviors at different flux levels or at different bias voltage levels. As a result, the components had to be changed a few times to reach a final design. All the improvements in the design of the power supply and the radiation tests will be discussed in detail.