A Detachable Tail Module for the Phase II ATLAS Pixel Upgrade

The entire tracking system of the ATLAS experiment will be replaced during the LHC Phase II shutdown, expected around 2025. A new silicon Inner Tracker will contain five innermost pixel layers equipped with new sensors and readout electronics capable to improve the tracking performance, cope with the high particle multiplicity and work in high luminosity environment provided by the LHC. The total surface area of silicon covered by the new pixel detector will be up to 14 m². About 10.000 pixel modules will be built for the Inner Tracker. Serial powering has been chosen for the Inner Tracker pixel detector in order to minimize the amount of service cables. A low mass support structure of the system will consist of long barrel staves and inclined sections, which will be situated close to the endcap regions. In order to standardize the detector modules for all regions of the Inner Tracker, the idea of a common hybrid flex for the modules was introduced to be used both for barrel and endcap regions. One solution for such a scheme will be presented, which uses specific detachable pigtails in the different regions in order to connect the common hybrid to further services. The flex design, construction and test results of such a detachable tail module will be discussed. At the moment a larger detector test setup for the outer barrel layers, the demonstrator, is being built at CERN. The module described above will be tested within the framework of the demonstrator program.