Design of a second generation firewire based data acquisition system for small animal PET scanners

The University of Washington developed a Firewire based data acquisition system for the MiCES small animal PET scanner. Development work has continued on new imaging scanners that require more data channels and need to be able to operate within a MRI imaging system. To support these scanners, we have designed a new version of our data acquisition system that leverages the capabilities of modern field programmable gate arrays (FPGA). The new design preserves the basic approach of the original system, but puts almost all functions into the FPGA, including the Firewire elements, the embedded processor, and pulse timing and pulse integration. The design has been extended to support implementation of the position estimation and DOI algorithms developed for the cMiCE detector module. The design is centered around an acquisition node board (ANB) that includes 65 ADC channels, Firewire 1394b support, the FPGA, a serial command bus and signal lines to support a rough coincidence window implementation to reject singles events from being sent on the Firewire bus. Adapter boards convert detector signals into differential paired signals to connect to the ANB.