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Micro-Focus X-Ray - Advanced NDT Technique

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X-Ray equipment in which the focal spot size is less than 100 µm is referred to as microfocus unit. Advanced micro-focus units have a focal spot size as low as 5 µm which is achieved by focussing the electron beam on the target in combination with sufficient cooling to avoid overheating. 

Micro-focus radiography facilitates to observe the minute details of the object through production of magnified X-ray images, which in turn enhances the flaw detection capability which improves reliability in comparison to conventional radiography. Micro-focus X-ray systems having focal spots that approach a point source are useful in obtaining very high resolution images due to the negligible penumbra effect.

The X-ray source generates a continuous beam of X-rays from the very small focal point. The beam passes through the sample placed on the manipulator turntable, and casts an X-ray projection onto the detector sensor. The sensor converts the transmitted X-ray projection into a visible greyscale image, which is displayed on a monitor. The magnification of the sample depends on its position between the X-ray source and detector. Moving the sample towards the X-ray source increases the magnification and improves the spatial resolution by increasing the number of pixels over which the X-ray image is projected. Even when operating at maximum magnification, the micro-focus X-ray spot ensures the image is always sharp. The associated software enables contrast enhancement and image integration.

TWI Resources

X-Tek HMX225 micro-focus advanced X-ray system

  • 5-10 µm Focal Spot Reflection Target X-ray Source

  • 25 to 225 kV, 0 - 2000 µA, 225 Watt

  • 5 axis fully programmable manipulator

  • Maximum scan area 480 x 450mm 

  • Geometric Magnification up to: 160x

  • System Magnification up to: 400x

  • Feature recognition: down to 5µm


  • Image Enlargement

  • Improved Radiographic contrast

  • Reliable detection of micro features


  • Inspection of integrated circuits and PCBs

  • Inspection of high quality castings and weld material

  • Tube to tube sheet weld inspection

  • Inspection of composites and ceramics for micro-voids and structural inhomogeneity

  • Inspection of inaccessible areas

  • Inspection of turbine blades of aero engine to detect hair line cracks

For more information about TWI's NDT services, please email

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