Seminars Archive

Fri 24 Nov, at 10:30 - Seminar Room T2

X-ray microscopy using radiation with high spatial coherence

Ulrich Vogt
Royal Institute for Technology/Albanova-Stockholm

In the first part of my talk I will present the efforts to implement the full-field transmission mode of the TWINMIC microscope at ELETTRA. Due to the high spatial coherence of the undulator beam used for the microscope illumination, a novel condenser concept had to be developed. It is based on a single-element diffractive optic which consists of a large number of small linear diffraction gratings. The condenser produces a Koehler-like homogeneous intensity distribution in the sample plane and eliminates object illumination problems connected to the high degree of spatial coherence in an undulator beam. The full-field mode of TWINMIC has been tested successfully in a number of test runs and is already open for user experiments. In the second part I will describe the two compact x-ray microscopes that are operated by the Biomedical and X-ray Physics group in Stockholm. The microscopes utilize radiation from laser produced plasmas as light source. Compared to radiation from undulator sources, laser plasma radiation is considered to have a very low spatial coherence. However, I will show that depending on the condenser design even in a compact microscope unwanted coherence artefacts can be observed in the images.

Last Updated on Tuesday, 24 April 2012 15:21