Silicon sensor development for the ATLAS upgrade for SLHC

The accelerator upgrade of the large hadron collider (LHC) to super-LHC is foreseen around the year 2015. The upgrade is to increase the luminosity to 1035 cm−2 s−1 and to accumulate 3000 fb−1. To cope with the increased occupancy and fluence, the transition radiation tracker (TRT) will be replaced with silicon microstrip sensors, and the semiconductor tracker (SCT) with short-strip silicon microstrip sensors. Both the ATLAS Pixel and SCT communities need to develop new sensors to work to fluences of 1×1016 1-MeV-neq/cm2 and to 8×1014, respectively. Technologies being investigated include a “3D sensor” for the Pixel layers, and an “n-in-p sensor” with high-voltage operation capability for the SCT. The “n-in-p sensor” requires n-strip isolation with high onset voltage of microdischarge. We report here on new sensors with various n-strip isolation structures that have been designed and are being fabricated in the search for the best approach.