A superconductive multi-hit time digitizer

We are developing an all-digital, high-speed, low-power superconductive multi-hit time digitizer based on a RSFQ time-to-digital converter (TDC). The advantages of this TDC, as compared to semiconductor TDCs, include excellent single, as well as multi-hit time resolution and extremely low power dissipation. Each TDC channel consists of a 14-bit superconductive counter based on toggle flip-flops with destructive readouts, a 9-word shift register-based FIFO memory, and a parallel-to-serial converter with output driver. To facilitate external control and data interfacing of the TDC, we have been developing a VXI-bus interface. Its low-power dissipation allows the TDC to be directly integrated with cooled front-end detectors, including optical detectors, eliminating cable bandwidth limitations.