Design of High-Speed Digital Readout System for Use in Proton Computed Tomography

Abstract

A team at the University of Bergen is developing a proton computed tomography (CT) scanner prototype. The proton CT (pCT) scanner will introduce fewer insecurities than conventional photon CT when analyzing the location of the tumor and the particle stopping power in the tissue in front of the tumor. The pCT will consist of multiple CERN-developed particle detector chips. This work covers the design and development of a readout system for the pCT scanner. The requirements for the different parts of the system are formulated. Particular emphasis is put on the clock data recovery method employed for handling the 1.2 Gb/s data transmitted from the detector chips. Because of the high number of detector chips in each scanner layer, transceivers cannot be employed for this purpose. This constraint results in a custom design employing the I/O primitives to achieve phase and word alignment automatically. A complete verification system is realized around a simulatable model of the particle detector chip. This system is used for verification of multiple readout procedures, as well as validation of detector chip communication and firmware functionality. The simulations are further verified in a physical hardware setup. The results of the I/O primitive approach are positive, but some errors are produced when employing longer cables.