  We propose a novel experiment, the Canfranc Axion Detection Experiment
(CADEx), to probe dark matter axions with masses in the range 330-460 $\mu$eV,
within the W-band (80-110 GHz), an unexplored parameter space in the
well-motivated dark matter window of Quantum ChromoDynamics (QCD) axions. The
experimental design consists of a microwave resonant cavity haloscope in a high
static magnetic field coupled to a highly sensitive detecting system based on
Kinetic Inductance Detectors via optimized quasi-optics (horns and mirrors).
The experiment is in preparation and will be installed in the dilution
refrigerator of the Canfranc Underground Laboratory. Sensitivity forecasts for
axion detection with CADEx, together with the potential of the experiment to
search for dark photons, are presented.
