Design and verification of a USB 3.0 readout system for Timepix3 hybrid pixel detectors

Abstract: This thesis describes the design, implementation, and verification of a USB 3.0 readout system for Timepix3 detectors. Timepix3 is a hybrid pixel detector consisting of a 256x256 pixel matrix with a 55 μm pitch and a timing resolution of 1.56ns. It allows to measure energy and time simultaneously utilising an event-driven data stream with a maximum data rate of up to 5.12 Gb/s or up to 85 million hits per second. Our aim is to implement a readout system that allows to add processing algorithms into the firmware, reducing the amount of data and the post-processing time. USB 3.0 was selected as an interface, because it provides a sufficient data rate and is present on all modern computers. Furthermore, the selected Opal Kelly XEM6310 development board provides a framework handling the communication between the FPGA and the host computer, FPGA components, and an API. We implemented a hardware adapter board in collaboration with the University of Glasgow connecting the development board to the detector chip board converting the detector’s output signals from SLVS to LVDS signals. Moreover, we implemented FPGA firmware consisting of a detector interface, USB interface, and a core including a processing interface. A multi-platform desktop library was implemented in C/C++ using Qt, which is used to configure the readout system and handles high speed data streaming. Data analysis and verification is conducted using custom build Python scripts. Simulations of the firmware showed the expected behaviour. The firmware and library were verified by configuring the detector, reading back the configuration, and measurements with an Americium source. An equalisation and a global and per-pixel energy calibration have been done successfully. Moreover, the system has been used to create and correct an X-ray image. Furthermore, the USB 3.0 data streaming performance was evaluated and it could be shown that the system can sustain a stream of around 380 MB/s. The proposed readout system has been implemented and was verified in simulation and experiments with X-ray radiation. USB 3.0 data streaming performed better than anticipated reaching higher speeds as stated by Opal Kelly. Furthermore, the firmware and the library function as intended. The hardware adapter requires some changes to accommodate higher data speeds and the data chan- nels have to be moved to different pins to allow synchronisation to an external clock.