Time Measurement System Based on Waveform Digitization for Time-of-Flight Mass Spectrometer

摘要

To guarantee a good resolution of a Time-Of-Flight Mass Spectrometer (TOF-MS), a high-performance time measurement system was required. This paper presents a time measurement system based on waveform digitization. The critical part, the 2-GSPS analog-to-digital converter is implemented using the Time-Interleaved Analog-to-Digital Conversion (TIADC) technique. Through a digital post-processing algorithm, the mismatch errors between the interleaving TIADC channels are corrected, which significantly improves the ADC performance. A Peripheral Component Interconnect (PCI) bus interface is used to communicate with a computer, achieving a data transfer rate up to 20 MByte/s using Direct Memory Access (DMA). Initial test results indicate that the system timing precision is about 196 ps Root-Mean-Square (RMS), which is good enough for the given requirements.