INTENSITY INTERFEROMETRY AT THE X13A UNDULATOR BEAMLINE

We are constructing an X-ray intensity interferometer and an undulator beamline to demonstrate intensity interferometry in the soft X-ray re gion. The 10-period X13 soft X-ray undulator at the National Synchrotr on Light Source will provide the coherent flux; the X13A beamline will preserve the brightness of the X-ray beam and provide sufficient temp oral coherence with a horizontally deflecting spherical grating monoch romator. Using the interferometer, which consists of an array of small slits, a wedge-shaped beamsplitter and two fast microchannel plate de tectors, we expect to measure the spatial coherence of the undulator b eam and therefore the size of the source. The beamline design and the interferometry experiment are discussed.