Design and high-speed tests of a single-flux-quantum time-to-digital converter for time-of-flight mass spectrometry

We are developing a single-flux-quantum (SFQ) time-to-digital converter (TDC) for time-of-flight mass spectrometry (TOF MS) system. In this study, we designed and tested a 24-bit SFQ TDC with a 3 × 24-bit FIFO buffer using the AIST Nb standard process (STP2), whose time resolution and dynamic range are 100 ps and 1.6 ms, respectively. The TDC design was improved to reduce the total junction numbers and the bias current in order to install it in a 4.2 K cryo-cooler. We confirmed the operation of the TDC and evaluated the jitter by measuring a histogram of TDC read out.