  Detection of low-energy nuclear recoil events plays a central role in
searches for particle dark matter interactions with atomic matter and studies
of coherent neutrino scatters. Precise nuclear recoil calibration data allow
the responses of these dark matter and neutrino detectors to be characterized
and enable in situ evaluation of an experiment's sensitivity to anticipated
signals. This article reviews the common methods for detection of nuclear
recoil events and the wide variety of techniques that have been developed to
calibrate detector response to nuclear recoils. We summarize the main
experimental factors that are critical for accurate nuclear recoil
calibrations, investigate mitigation strategies for different backgrounds and
biases, and discuss how the presentation of calibration results can facilitate
comparison between experiments. Lastly, we discuss the challenges for future
nuclear recoil calibration efforts and the physics opportunities they may
enable.
