X-ray microscopy

The well-established way to obtain the ultimate resolution is to use X-ray optics. This imaging technique is since many years performed at synchrotrons, since they can provide a high brilliance monochromatic beam. In recent decades, the optics-based X-ray microscope based on laboratory sources are commercially available.

The X-ray optics limits the bandwidth of the spectrum, thus a high brightness and relatively monochromatic X-ray source is needed. The conventional laboratory-based X-ray microscopes often use high-power rotating-anode sources. The drawback of this setup is the high loss of flux, since the acceptance angle of the optics will strictly limit what radiation that can become useful. A MetalJet source offers a sharp, high-intensity Kα line from Gallium emitted from a small focal spot, making a considerably larger fraction of the flux useful in the optics setup. This higher brightness makes broad applications possible also on compact sources.

Schematic of high-resolution optics-based X-ray microscope. Just like in a visible light microscope, the condenser optic illuminates the sample and the high-resolution objective images the sample to the detector.

NanoTube for X-ray microscopy

The Excillum NanoTube is based on advanced electron optics refined from the MetalJet e-beam platform and the latest tungsten-diamond transmission target technology. In the NanoTube, the bulk anode is replaced by a cutting-edge thin tungsten layer on top of a diamond substrate, which is transparent to X-ray and has good thermal conductivity. This makes it possible to achieve a smaller focal spot size compared to the conventional transmission type tube where the electron diffusion in the bulk anode material makes this difficult. As a consequence, it enables an unprecedented true resolution of e.g. repetitive patterns of 150 nm lines and spaces such as JIMA or Siemens star.  Automatic e-beam focusing and astigmatism correction ensures that the smallest possible truly round spot is achieved at any voltage and current setting. The NanoTube has the unique feature that it internally measures and reports the current spot size. In addition, advanced cooling and thermal design lead to its extreme stability over long-time exposure.

Features and benefits

  • True small X-ray round spot for 2D/ 3D imaging with isotropic high resolution
  • Ultimate spot stability, guaranteed by long-time measurement
  • Automatic E-beam focusing and astigmatism correction at each user defined tube setting.
  • Cone-shaped front surface of the tube for excellent geometric access to the focal spot
  • Absolute internal spot size measurement
  • User-friendly graphic user interface and API support
  • Capability of shifting E-beam within target area

MetalJet for X-ray microscopy

The MetalJet is Excillum’s patented, high-brilliance micro-focus X-ray source.  It uses a fast-flowing liquid jet of metal instead of a solid anode metal target, thereby allowing a greater power loading to be placed on the metal target. The high-speed jet efficiently transports heat away from the interaction point and quickly regenerates the alloy. In this way, the MetalJet can generate a much higher-brilliance than conventional solid anode X-ray tubes.

Features and benefits

  • Extreme microfocus source power, with ~10x higher brilliance than conventional microfocus X-ray tubes
  • Small, adjustable and well-defined X-ray spot
  • Stable X-ray emission and spot position, which is essential for long-time measurements
  • User-friendly Graphical User Interface with remote control through TCP/IP protocol for full control of source settings
  • User selectable e-beam size and position on the metal-jet enables variable take-off angle, to adjust X-ray spot size, flux and spectrum hardness
  • Advanced e-beam technology and algorithm for internal absolute spot size calibration in micrometers
  • Unique target material enables the use of characteristic lines
  • Optional dual-port mode, enables two setups from the same source

Application examples

The periodic line patterns at the inner of a Siemens star, with 150 nm lines and spaces, can be resolved with the X-ray microscope based on the MetalJet D2 source. The image was taken with a Fresnel zone plate as objective. 

C. Fella, et al., “Hybrid setup for micro- and nano-computed tomography in the hard X-ray range”, Rev. Sci. Instrum. (2017); 

From the same publication, a volumetric rendering of the CT of a bent ~ 4 µm tip of the bend tip of a damaged injection cannula with X-ray microscope based on Excillum’s MetalJet source. The voxel size was 147 nm.

Unless otherwise stated, pictures and content is published under license for CC-BY (https://creativecommons.org/licenses/by/4.0/​).

Recommended products for X-ray microscopy

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