A transparent two-dimensional in situ beam-position and profile monitor for synchrotron X-ray beamlines

A compact, inexpensive and easy-to-construct two-dimensional in situ beam-position and profile monitor for synchrotron X-ray beamlines is presented. The device is based on the collection of spatially resolved scattered radiation from a polyimide foil. The X-ray beam passes through a foil placed in the path of the beam, which absorbs no more than 3% of the beam at 12 keV. The scattered radiation is collected at an angle of 90 degrees through a collimator located below the foil onto a CCD sensor. The device was tested on bending-magnet beamline BM26 at the ESRF synchrotron radiation source and has a positional sensitivity better than 10 microm with a large working range of 25 mm x 25 mm. Although the device is optimized for use in the range 10-12 keV, it can easily be modified for use with higher-energy beams by using a suitably chosen scattering foil.