SXM II end-station

3D view of the ID21 Scanning X-ray microscope

Microscope chamber

The X-ray microscope is housed in an environmental chamber allowing operation in air or vacuum (10^-4-10^-6 mbar). A Kapton exit window separates the microscope environment from the beamline vacuum. A load-lock system allows fast exchange of samples under vacuum, and greatly facilitates operation under cryogenic conditions.

Focusing optics

The microscope can now host two different optical focusing configurations: either zone plates (ZP) or a Kirkpatrick-Baez mirror system (KB), which routinely achieves a typical spot size of 0.35 x 0.7 µm² with a photon flux of 10⁹-10¹⁰ photons/s. The KB system has been developed at ESRF and is based on elliptically shaped fixed-focus Ni coated mirrors. Its compact design ensures high mechanical / thermal stability and a short focal length for high source demagnification. The advantages of the KB configuration are its higher photon flux and its achromaticity which is preferable for µXANES

Detectors

The SXM is equipped with a large area (80 mm²) Sirius Silicon Drift Diode (SDD) from RaySpec.

Sample stage and sample environments

The sample is scanned using a combination of piezo driven flexure and mechanical stages giving a total scan area of 20 x 20 mm².

The sample support comprises two translation stages. A system of coarse mechanical xy-stages driven by stepper motors allow sample alignment and scanning over a range of +/-10 mm with measured resolutions of 1µm. For finer scanning resolutions a commercial piezo-driven monolithic xy-flexure stage (Physik Instrumente) allows sample scanning over a range of 100 µm. This system, equipped with integrated capacitive encoders allows positioning resolutions of about 10nm.

The sample stage can accommodate various sample holders depending on the nature of the sample (solid, liquid or frozen). Please see the sample preparation and cryo-stage sections for further details.

Sample visualisation and control of the microscope

A visible light video-microscope allows visualisation of the sample, even under vacuum, for precise alignment in the beam.

Control of the SXM is now performed through a fully integrated graphical user interface "Daquiri" which includes on-line visualization of the sample through a video-microscope, and direct “grabbing” of regions to be scanned from a video image.