Speaker
Description
A major upgrade of the ALICE experiment is foreseen for Run 5 of the LHC. The new retractable Vertex Detector (VD) is a crucial component of the upgraded experiment and will achieve an unprecedented pointing resolution owing to its close proximity to the interaction point, with three layers installed inside the beam pipe, in combination with a low material budget. Monolithic Active Pixel Sensors (MAPS) are ideally suited, yet require significant research and development to meet the combined requirements in position and time resolution as well as radiation hardness, all while limiting the power consumption. In addition, the desired position resolution of 2.5 µm, that is achievable with a pixel pitch of 10 µm, requires an unprecedented integration density.
To this end, small pitch analogue prototypes are characterised in view of their charge collection properties, in order to pave the way towards a pixel chip targeting the requirements of the ALICE 3 VD. A second variant of the pixel chip is adapted to the needs of the outer tracker layers (barrel and forward disks) surrounding the VD up to a radius of 80 cm.
In this contribution, the pixel chip requirements and design concepts for the VD and outer layers will be presented. Particular focus will be given to the characterisation of prototypes to validate the required technological steps towards ALICE 3, including laboratory measurements and test beam campaigns.