  Echoing classical physics, quantum electrodynamics predicts the release of a
spectral continuum of electromagnetic radiation upon the sudden acceleration of
charged particles in quantum matter. Despite apparent theoretical success in
describing sister nuclear processes, known as internal bremsstrahlung,
following nuclear beta decay and K capture, the situation of the photoejection
of an electron from an inner shell of an atom, intraatomic bremsstrahlung
(IAB), is far from settled. In this paper we present fresh measurements which
rely on contemporary signal processing as well as the high flux available from
a synchrotron radiation source to revisit the problem by photoejecting
electrons from the innermost shell of copper. For the first time we have
sufficient sample statistics to measure the expected spectra at the level
expected by contemporary theory. Furthermore, we employ sufficiently thin
targets to overcome secondary scattering artifacts. Our approach applies the
fluorescence coincidence method to guard against extraneous scattering and
multiple incident photon processes. Our observations set a severe upper limit
on the rate for IAB: We conclude that current theory overpredicts, by at least
5 sigma, the measured rate for K shell IAB in copper in the range of detected
energies below the K fluorescence energy.
