  Using synchrotron radiation-based Laue diffraction methods, we have searched
for structural anomalies in a single-crystal whisker of the heavy fermion
superconductor UPt_3. Our data cover a large volume of k-space with high
sensitivity. We find no signs of the structural modulations seen in
transmission electron microscopy studies of whiskers grown under identical
conditions. Our result has consequences for theories of symmetry-broken
superconductivity in this material.
