Refractive lenses as a beam diagnostics tool for high-energy synchrotron radiation

Parabolic compound refractive lenses (CRLs) for hard X rays have been used to image the electron beam at undulator and bending-magnet beamlines at the ESRF. The measurements yield the shape and size of the synchrotron radiation source, and show that CRLs with paraboloid surface shape can be used as a beam diagnostics tool at highenergy electron storage rings. The optical resolution of the imaging setup can be as small as 4 mm. This is smaller than typical values of the electron beam size in third-generation synchrotron sources. We report measurements at two ESRF beamlines and resolution calculations taking into account the properties of synchrotron radiation and the transmission characteristics of the CRLs used. # 2001 Elsevier Science B.V. All rights reserved.