1 / 44

X-ray powder diffractometer

X-ray powder diffractometer. X-ray powder diffractometer. radiation counter. X-ray powder diffractometer. Powder diffractometer (see Jenkins & Snyder, chap. 7). Powder diffractometer (see Jenkins & Snyder, chap. 7). Bragg-Brentano geometry. X-ray powder diffractometer.

shanag
Download Presentation

X-ray powder diffractometer

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. X-ray powder diffractometer

  2. X-ray powder diffractometer radiation counter

  3. X-ray powder diffractometer

  4. Powder diffractometer (see Jenkins & Snyder, chap. 7)

  5. Powder diffractometer (see Jenkins & Snyder, chap. 7) Bragg-Brentano geometry

  6. X-ray powder diffractometer

  7. X-ray powder diffractometer

  8. X-ray powder diffractometer

  9. X-ray powder diffractometer

  10. X-ray powder diffractometer

  11. X-ray powder diffractometer

  12. X-ray powder diffractometer

  13. X-ray powder diffractometer

  14. X-ray powder diffractometer

  15. X-ray powder diffractometer

  16. X-ray powder diffractometer

  17. X-ray powder diffractometer

  18. X-ray powder diffractometer To maintain the focusing geometry, when counter is rotated at rate of 2/min, specimen is also rotated at rate of /min /min /min

  19. Powder diffractometer Bragg-Brentano instrument - errors (see Klug & Alexander) Axial divergence - axis, here, is main rotation axis - asymmetric broadening toward low 2 - negative 2 error up to 90° - positive 2 error beyond 90°

  20. Powder diffractometer Bragg-Brentano instrument - errors (see Klug & Alexander) Axial divergence - axis, here, is main rotation axis

  21. Powder diffractometer Bragg-Brentano instrument - errors (see Klug & Alexander) Axial divergence - axis, here is main rotation axis each section of Soller slit produces its own Debye ring from a specific region in the specimen divergence angle typically ±2.5°

  22. Powder diffractometer Bragg-Brentano instrument - errors (see Klug & Alexander) Axial divergence - axis, here is main rotation axis each section of Soller slit produces its own Debye ring from a specific region in the specimen divergence angle typically ±2.5°

  23. Powder diffractometer Bragg-Brentano instrument - errors (see Klug & Alexander) Flat specimen peak shifts to lower 2 & asymmetric broadening depends on beam divergence & 2, plus specimen shape

  24. Powder diffractometer Bragg-Brentano instrument - errors (see Klug & Alexander) Specimen transparency

  25. Powder diffractometer Bragg-Brentano instrument - errors (see Klug & Alexander) Specimen displacement Usually largest error in expt'l data Neg. peak shift - ~0.01° 2/15displacement Asymmetric broadening toward lower 2

  26. Powder diffractometer Bragg-Brentano instrument Divergence slit choice

  27. Powder diffractometer Bragg-Brentano instrument Divergence slit choice Or, theta-compensating slit - divergence slit opens as theta increases

  28. Powder diffractometer Bragg-Brentano instrument Receiving slit choice

  29. Powder diffractometer Bragg-Brentano instrument Receiving slit choice lowers intensity - little improvement in resolution poor resolution - little improvement in intensity

  30. Powder diffractometer Bragg-Brentano instrument Receiving slit choice correct slit size ~0.15°

  31. Powder diffractometer Alignment steps

  32. Powder diffractometer Alignment steps Align to focal spot Set take-off angle

  33. Powder diffractometer Alignment steps Align to focal spot Set take-off angle Zero alignment 2:1 alignment

  34. Powder diffractometer Alignment steps Align to focal spot Set take-off angle Zero alignment 2:1 alignment

  35. Powder diffractometer Alignment steps Align to focal spot Set take-off angle Zero alignment 2:1 alignment

  36. Powder diffractometer Alignment checks Run calibration pattern - use suitable standard NIST 640c (Si)

  37. Powder diffractometer Alignment checks Run calibration pattern - use suitable standard

  38. Powder diffractometer Alignment checks Run calibration pattern - use suitable standard Watch for: Intensity loss Angle shifts Resolution loss

  39. Powder diffractometer Alignment checks

  40. Powder diffractometer Alignment check "Five fingers of quartz"

  41. Powder diffractometer Alignment check "Five fingers of quartz" Measure: position & intensity of (203)1 H1/H2

  42. Powder diffractometer Alignment checks Run calibration pattern - use suitable standard NIST 1976 (Al2O3)

  43. Powder diffractometer Alignment checks Run calibration pattern - use suitable standard

  44. Powder diffractometer Alignment checks Run calibration pattern - use suitable standard

More Related