Testing the pALPIDE v2 chip and researching module testing methods for the ALICE ITS upgrade.

Abstract

In the second Long Shutdown (LS2) of the LHC at CERN in 2018-2019, an upgrade of the one of the detectors, namely ALICE is planned to take place. A crucial part of the ALICE detector in identifying particles is Inner Tracking System (ITS). The main purpose of the ITS, which is the closest to the beam pipe, is to detect low momentum and short-lived particles. In the new ITS, a Monolithic Active Pixel Sensor architecture called the pALPIDE v2 is chosen to replace the current detector chips. A testing system for these chips including a MOSAIC board that converts the analogue to a digital signal that can be read out numerically by a computer has already been developed to test the chips. This setup also consists of a printing board that the chip is fixed on and a power supply. In the ITS, staves that consist of modules of 7 by 2 chips will be installed. Therefore it is necessary to be able to test multiple chips at once. Connecting multiple chips to each other and testing these modules as a whole is a delicate procedure since the silicon layers on the chip can easily be damaged. Two connection methods have been developed so far that are both undergoing a research en development phase. Firstly, the probing machine presses a single module down onto connector pins in order to make a connection and read out data for testing. Secondly, the FPC cutting machine cuts off a small strip at the end of a module to provide a connection using an external connector. In this process of cutting, the straightness of the cut is of utmost importance. In this bachelor thesis I have examined the possibilities for both the module testing methods as well as supplied a statistical analysis of a single chip in ROOT.