Hybrid and module designs for ATLAS silicon tracker upgrade for super LHC

Abstract

Based on the ATLAS SCT experience, hybrid and module designs of a short strip silicon detector for an upgraded ATLAS inner tracker for the super LHC have been pursued. At the super LHC, which provides 10 times more intense beam collisions than the LHC, the detectors envisage a very high rate operation in a much harsher radiation environment. Immediate concern is an increase of leakage current due to a radiation damage, which may induce a catastrophic break down of a thermal runaway. We have deduced a simple model for the thermal runaway, which can be conveniently utilized for the module designs. The thermal runaway model was verified by comparing with the corresponding FEM thermal analyses. The upgraded module is structurally similar to the present SCT barrel module. Two rectangular sensors, each of 12.5 × 6.4 cm 2 , are sandwiched along with a thermo-mechanical baseboard to provide two-dimensional space points. A one-piece wrap-around hybrid bridged over the sensors serves both the top and bottom sensors. Mounting and cooling schemes also follow the present barrel SCT designs with necessary modifications and improvements.