University of Manchester

XTEK high flux

The Bay The High Flux Nikon XTEK bay at the Henry Moseley X-Ray Imaging Facility (HMXIF) has been specifically designed for time lapse X-ray Computed Tomography and allows the use of large in-situ rigs to be fitted within the enclosure for time lapse studies involving compression, tension, torsion, fatigue, fluid flow or heating of specimens. To facilitate high speed XCT scans the system is outfitted with high speed cabling, and both acquisition and reconstruction instruments are outfitted with solid state drives for increased bandwidth. The bay permits the analysis of large specimens up to 200 millimetres in cross-section. The additional height of the custom bay also permits long specimens, up to 800 mm, to be imaged via multiple scans. In these cases the scans are linked and the data are knitted together during the reconstruction stage. Two high specification 120GB RAM workstations with GPU reconstruction capability are linked to the 320/225 kV Nikon XTEK bay for rapid data reconstruction and processing.

External control Unlike cabinet systems, the bay is additionally fitted with two labyrinth systems for the external control and monitoring of user-installed equipment during scanning.

Internal features The heavy duty 5-axis specimen manipulator stage that is capable of supporting specimens of 100 kg (50kg maximum weight directly on to the manipulator stage) The stage also allows the attachment of specialist rigs that are designed for in-situ 4-D analysis (compression, tension and temperature) using the range of in situ rigs that are avail-able within the facility.

Two interchangeable X-ray sources:

  • 2 micron optimal spot size transmission rotating target (prototype) with the capability of emitting 60W
  • 10 micron optimal spot size reflection rotating target with the capability of emitting 450W
  • A number of filters (Cu, Al, Ag, Sn) can then be used to modify the emitted X-ray beam energy spectrum in order to optimise the radio-graph contrast
  • High speed detector PerkinElmer XRD 1611 xP flat panel X-ray detector The panel is a single substrate amorphous silicon active TFT/diode array. The scintillator is encased in an Aluminium frame with a Carbon-fibre window. The detector is fitted on a movable arm that can be remotely controlled. General features of the detector are:

  • 100 μm pixel pitch (optimum)
  • Pixel matrix 4096 (width) x 4096 (height)
  • A dynamic range over 84 dB
  • Live frame rates up to 3.75, 7.5 & 7.5 fps for matrix settings of 4096x4096, 2048x2048 & 1024x1024 respectively
  • 16 bit readout
  • 65,536 grey levels
  • Suitable for a wide range of X-Ray energies - 20 kV — 15 MV
  • Selectable gain setting
  • Galvanic isolation by fibre-optical interface
  • Reduced scan times Typical scan times using the High Flux Nikon XTEK bay will be significantly quicker than anything previ-ously available at MXIF. The graph below shows X-ray spot size vs Power (W) for the static transmission, static reflection and rotation reflection sources below 40W (Data provided by Nikon XTEK). For equivalent spot size the rotating targets provide increased power resulting in reduced scan times.

    Range of resolutions The resolution will vary from 2 to 119 microns for specimen areas with a diameter of < 8 mm and up to 202mm diameters respectively. The graph below showing Voxel resolution vs Field of View for the 320 kV reflection target (Red) and the 225kV tungsten rotating anode (Blue) X-ray sources. Maximum field of view is limited by the manipulator travel. It should be noted that the achievable resolution will depend upon both the specimen and a number of other factors.