University thesis:
Dissertation, Albert-Ludwigs-Universität Freiburg, 2017
Footnote:
Description:
Abstract: The COMPASS-II experiment at CERN addresses open questions regarding the partonic structure of the nucleon. Many aspects of the physics program require hadron identification. For this purpose, the COMPASS-II apparatus includes a ring-imaging Cherenkov detector that was upgraded in 2016 with a set of new photon detectors based on micro-pattern gas detector technologies. The objective of this thesis was the development of a time-to-digital converter (TDC) module that provides the digital readout capabilities in view of these photon detectors.<br> <br>Four field-programmable gate array devices per module implement TDCs processing 384 detector channels with an average time resolution better than 168 ps. The TDC design is based on an interpolation principle. The interpolators receiving the input signal consist of eight flip-flop components that are sampled in successive order by a multiphase clock. Thereby, the timing of the input signal with respect to the preceding clock edge is encoded from the readings of the interpolating flip-flops. The measuring range is enlarged using a coarse counter. The characteristic parameters of the TDC firmware have been thoroughly characterized. The results are detailed in the thesis at hand.<br><br>The hardware layout features advanced optical interfaces that enable fiber-optic communication with up to seven boards as satellites. On this account, a constant-latency up-link for clock and trigger signal distribution is implemented. In down-link direction, event building capabilities processing the received data of in total eight boards yielding 3072 detector channels are provided for output to the data acquisition system