A simple and direct interferometric technique for characterization of the s
ource size and the transverse coherence length of synchrotron hard X-rays i
s discussed. A high level of spatial coherence of the X-ray beam allows us
to detect the diffraction images (phase contrast patterns) of both the boro
n fiber of about 100 mum diameter and the slit of different widths. We char
acterize the level of coherence by comparison of the measured visibility of
the interference fringes with the theoretical values by means of simple an
alytical formulas derived in this work. The analytical theory of both the f
iber and the slit diffraction images is discussed in details. The results o
btained analytically are confirmed by computer simulations. The proposed te
chnique is well suited for third-generation synchrotron sources and was app
lied at the European Synchrotron Radiation Facility. (C) 2001 Elsevier Scie
nce B.V. AM rights reserved.