Two-dimensional Synchrotron Beam Characterisation from a Single Interferogram

Double-aperture Young interferometry is widely used in accelerators to provide a one-dimensional beam measurement. We improve this technique by combining and further developing techniques of non-redundant aperture masking and self-calibration from astronomy. Using visible synchrotron radiation, tests at the ALBA synchrotron show that this method provides an accurate two-dimensional beam transverse characterisation, even from a single 1ms interferogram. The technique is resistant to phase fluctuations that might be introduced by vibration of optical components, or in the laboratory atmosphere.