Abstract
A fast data acquisition (DAQ) system for axion dark matter
searches utilizing a microwave resonant cavity, also known as axion
haloscope searches, has been developed with a two-channel digitizer
that can sample 16-bit amplitudes at rates up to 180
MSamples/s. First, we realized a practical DAQ efficiency of greater
than 99% for a single DAQ channel, where the DAQ process includes
the online fast Fourier transforms (FFTs). Using an IQ mixer and two
parallel DAQ channels, we then also implemented a software-based
image rejection without losing the DAQ efficiency. This work extends
our continuing effort to improve the figure of merit in axion
haloscope searches, the scanning rate.