Real Time Micro-focus X-ray is an extension of digital radiography and uses related technology to that used for scanning electron microscopy. It enables X-ray images to be viewed in real-time and allows for computerised treatment of the images to enhance resolution or to enable pattern-recognition algorithms to be used. Its main application is to the inspection of electronic components and small critical components. The NDT Validation Centre uses an X-Tek HMX225 micro-focus X-ray system. Figure 1 is an overall view of the chamber and Fig.2 shows the X-ray gun. The HMX225 is an advanced system, capable of resolving details down to 5 microns, and with magnifications up to 160X. It has the following characteristics: -

• 5 µm Focal Spot Reflection Target X-ray Source, 25 - 160 kV or 25 to 225 kV, 0 - 2000 µA (non continuous) 60 or 225 Watt
• 5 axis fully programmable manipulator
• Maximum scan area 480 x 510mm (480 x 680mm in 2 scans)
• Geometric Magnification up to: 160x
• System Magnification up to: 400x
• Feature recognition: down to 1 micron

The sample can be manipulated with 5 axes of freedom, whilst continuously viewing the image on a monitor. Defects can be rapidly located, zooming in for detailed analysis.

The system functions as follows. The X-ray source generates a continuous beam of X-rays from a 5-micron spot. The beam passes through the sample placed on the manipulator turntable, and casts an X-ray shadow onto the intensifier window. The intensifier converts the X-ray shadow into a visible image, which is recorded by a digital video camera and displayed on a monitor. The magnification of the sample depends on its position between the X-ray source and intensifier. Moving the sample