Development of an adjustable Kirkpatrick-Baez microscope for laser driven x-ray sources at CLPU

A prototype of a highly adjustable Kirkpatrick-Baez (KB) microscope [1] has been designed, built, and tested in a number of laser-driven x-ray experiments using the high power (200 TW) VEGA-2 laser system of the Spanish Centre for Pulsed Lasers (CLPU). The presented KB version [2] consists of two, perpendicularly mounted, 500µm thick silicon wafers, coated with a layer of platinum, a few tens of nm thick. Unlike the usual millimeter thick glass substrate, this design allows for a larger bending flexibility and large adjustment range. According to simulations, this KB microscope offers a broad-band multi-keV reflection spectra (1eV to 20keV), allowing more spectral tunability than conventional Bragg crystals. In addition, to be vacuum compatible, this prototype is characterized by relatively small size (21cm×31cm×27cm) and permits remote control and modification both of the radii of curvature (down to 10m) and of the grazing incidence angle (up to 60mrad). A few examples of focusing performance tests and experimental results are discussed.


[1] Albert V. Baez, “Fresnel zone plate for optical image formation using extreme ultraviolet and soft x radiation” Journal of the Optical Society of America 51, 4 (1961). [2] G. Zeraouli et al., “Development of an adjustable Kirkpatrick-Baez microscope for laser-driven x-ray sources” Review of Scientific Instruments, 90, 063704 (2019).