Towards minimum material trackers for high energy physics experiments at upgraded luminosities

Reducing material in silicon trackers is of major importance for a good detector performance overall, and poses a big challenge in the development of the detectors. To match the low material desirable for trackers in High Energy Physics experiments at upgraded luminosities, special techniques have to be developed to address the main sources of material, i.e. mechanical structure and services, and to prevent new significant contributions to the detector material coming for instance from larger Front-End chips. In this framework three methods are developed to reduce the material added by services and electronics: (1) serial powering, (2) light weight aluminum flex cables and Through Silicon Vias, and (3) thin Front-End chips. The methods are presented in this paper using the upgrades of the ATLAS pixel detector as an example of application.