Speaker
Description
ATLAS is currently preparing for the HL-LHC upgrade, with an all-silicon Inner Tracker (ITk) that will replace the current Inner Detector. The ITk will feature a pixel detector surrounded by a strip detector, with the strip system consisting of 4 barrel layers and 6 endcap disks.
The basic building block of the ITk Strip detector is the “module,” composed of front-end electronics glued to a silicon microstrip sensor. A critical problem was encountered during pre-production of ITk Strip modules when it was found a significant fraction of silicon sensors cracked due to thermal stresses when glued to local support structures and brought to cold operating temperatures.
A taskforce was established, and an extensive program of simulations, test setups and research arrived at 2 possible solutions. The use a stress-relieving layer (interposer) into the module assembly process, and the optimisation of glue patterns.
Results from the taskforce, including simulations, radiation studies and quality control testing are shown for modules and their loaded local supports. These solutions have allowed the recommencement of Strip Module production.
