Testing the pALPIDE v2 chip for the upgrade of the ALICE Inner Tracking System

Abstract

In the second long shut down of the LHC at CERN scheduled in 2018-19 a big upgrade of the ITS of the ALICE detector is planned. In light of this we discuss what the current state is of our view of the Standard Model, how Quantum Chromodynamics plays a role in it and how the gaps that are still left open can be answered by the study of Quark Gluon Plasma. When the goals in this theoretical view are set we discuss which of these are of interest to the ALICE collaboration, what the current performance and limitation are of the ALICE detector and how the ITS upgrade is going improve the current performance. Among many key aspects of the ITS is the pixel sensor system the most important and for this upgrade the new Monolithic Active Pixel Sensor architecture ALPIDE is chosen because of its best fit with the requirements set by the ALICE collaboration. One of the chips that is used to explore electrical and mechanical testing possibilities is the pALPIDEv2 chip. This chip is embedded on a flex printed circuit for which we developed a cable to connect it with a MOSAIC board. Furthermore was a power grid developed to connect it with a 5V power supply. After connection was made the chip was tested on several important qualities that not only determined how well the tested chip matches the requirements of the ALICE collaboration but also explores the possibilities of future tests. The chip has four distinct pixel areas which are compared on their thresholds, noise and faulty pixels. By extracting the data with a C++ written program further statistical analysis could be performed after developing applicable Root programs. After showing significant differences in threshold, noise and faulty pixels this paper leaves a lot of room for further research i.e. testing this chip or upcoming versions of the ALPIDE-chip in an array.