  The \emph{muX} project is conducting a series of muonic X-ray measurements in
medium- and high-Z nuclei at PSI, utilizing a high-purity germanium detector
array, in-beam muon detectors, and a modern digital data-acquisition system. A
novel hydrogen target for muon transfer was developed, enabling measurements
with as little as a few micrograms of target material. First measurements with
radioactive Cm and Ra targets were conducted, aimed at determining their
nuclear charge radii. These serve as important input for upcoming atomic parity
violation experiments. The apparatus is also used to perform a feasibility
study of an atomic parity violation experiment with the $2s-1s$ muonic X-ray
transition. In addition, the setup has been made available for a wider range of
nuclear, particle, and solid-state physics measurements.
