Inbetriebnahme eines laserbasierten Testsystems für CMS Phase-1 Pixelsensoren

To further increase the accuracy and efficiency of the CMS Inner Tracker a new generation (Phase-2) of pixel sensors is required. However, new approaches must first be validated on the current sensor generation (Phase-1) with test systems.

This bachelor thesis commissions such a laser-based test system, which can perform the Alive and the S-curve test as well as the Trim calibrations. Furthermore, the use of the laser enables the spatially resolved simulation of particle radiation without exposing the sensor to high-energy radiation. With a sample sensor and the software pxar the required functionalities are implemented, and the focal point of the laser is determined.

During the analysis of the sample’s IV-characteristic, an unexpected hysteresis was measured, most probably caused by thermal effects. Furthermore, examination of the laser focal point with Gaussian optics yields a focal length of 9mm 9 \,\mathrm{mm} . However, the determination of the focal length is limited by the pixel size and charge sharing effects. Nevertheless, the results indicate that the setup can perform tests and calibrations that could be used in the development process of the next generation of pixel sensors. In addition, a future upgrade could offer the possibility to test also manufactured Phase-2 pixel sensors.