Calibration techniques for a fast duo spectrometer

We have completed the upgrade and calibration of the ion dynamics spectrometer (IDS), a high-speed Doppler duo spectrometer which measures ion flow and temperature in the MST reversed-field pinch. This paper describes an in situ calibration of the diagnostic’s phase and frequency response. A single clock was employed to generate both a digital test signal and a digitizer trigger thus avoiding frequency drift and providing a highly resolved measurement over the system bandwidth. Additionally, we review the measurement of the spectrometer instrument function and absolute intensity response. This calibration and subsequent performance demonstrate the IDS to be one of the fastest, highest throughput diagnostics of its kind. Typical measurements are presented.