1. Diffraction Enhanced Imaging at the UK Synchrotron Radiation Source M.Ibison, K.C.Cheung, K.Siu, C.J.Hall, R.A.Lewis, A. Hufton, S.J.Wilkinson, K.D.Rogers, A.Round

2. Principal Objectives of DEI Development Activities at the SRS  reduce the proportion of available time spent on alignment, in preparation for useful imaging  increase reliability and stability in mechanics and software, to improve image quality  approach a ‘turn-key’ facility for DEI users without need for expertise in the detailed method. Also:-  obtain useful experience for designing 2 nd generation DEI on higher-energy SRS station.

3. DEI System – Station 7.6 High precision optics required 2-crystal monochromator and 2- crystal analyser Si 311 crystals give sharper x-ray extinction Higher contrast, higher resolution images.

4. X-Ray Optics Alignment Laser red beam ( = 623nm), <1 mW output compact (2.5cm x 1cm), power source = 2 x 1.5V batteries micrometer adjustments, Vertical & Horizontal angle & displacement spot of 2mm x 1mm at working range of 2m

5. Monochromator and 4-Crystal Alignment using Laser Assistance Monochromator AlignmentAnalyser Alignment NOTE: Vertical Spacing between crystals exaggerated for clarity.

6. Laser Method for Determination of Motor Drive Calibration Factors

8. Ionisation Chamber for X-Ray Beam Location polymer window (5cm x 1cm) thickness = 70  m atmospheric pressure

9. Silicon p.i.n. PhotoDiode for DEI Alignment Sensitive Area: 3.5mm x 3.5mm Thickness (effective): 250  m Window: 10  m Al foil (for 14keV X-rays)

10. Medical Applications of DEI: Mouse Feet Study Refraction Images Normal Diseased vertical view through sole of foot Absorption Images Normal Diseased

11. Mouse Feet Study (2) Normal   Diseased Refraction Images horizontal view through side of foot Absorption Images Normal   Diseased

12. DEI Insect Studies Refraction Image Absorption Image Beetle Earwig

13. Computerised Tomography – Principles

14. Examples of CT Reconstruction Input to Reconstruction = Set of Projections (Sinogram) Results of Reconstruction = Cross-Section (Slice)

15. Effect of Filtering on Reconstructed Image UnfilteredFiltered

16. Volume Visualisation 3-D Rendering of a Mouse Liver, based on CT dataset (ELETTRA) Uses Volume/Surface modelling features of software packages

17. Second-Generation DEI System: Some Design Considerations  higher energy and greater flux (on wiggler Station) - better penetration, lower subject dose  channel-cut crystals - facilitate alignment, reduce drift  rigidity and anti-vibration built into support structure  mountings optimize use of existing framework - station sharing remains feasible  vacuum enclosure of the monochromator - avoids convection currents and ozone damage risk  cooling provision for the 1 st crystal - highest heat loading from ‘white’ beam.

18. Acknowledgements The authors would like to thank:- Medical Research Council - for funding this research programme Giuseppe Salvini and Janet Groves (CLRC Daresbury) - design and construction of the p.i.n. diode device Greg Johnson (CLRC Rutherford Appleton Laboratory) - design and implementation of DSP reconstruction system Andrew Mather (Liverpool University) - Java implementation of the FBP reconstruction software.