1. Absolutely Calibrating an Energy Dispersive Detector Patrick Ross Spring Research Conference

2. Why? Absolute Calibration provides more information. Applications in Medical Research Materials Science Use in material analysis (X-Ray Diffraction/ X-Ray Florescence) Use in material analysis (X-Ray Diffraction/ X-Ray Florescence)

3. Our Detector

4. CCD: A spacially resolving detector

5. Methods of Calibration We are attempting to calibrate the detector using a calibrated source (±5%). We confirmed the source’s calibration with: Proportional Counter PIN Diode

6. Proportional Counter

8. Problems with the Proportional Counter Obscure geometry of detector Pressure problems (P-10 Gas) Solid angle problems (measuring the depth of the window)

9. PIN Diode

14. Calibrating the CCD X-ray source Detector 1 Detector 2

15. So, how is a CCD an energy dispersive detector? It isn’t, But…

16. Von Hamos Spectrometer

17. Single Crystal CCD λ λ’λ’ θθ’θ’

18. Increasing the Signal to Noise Von Hamos spectrometer disperses according to wavelength. With the energy calibration, background counts can be eliminated.

19. Thanks to: Dr. Larry Knight Sterling Cornaby Arturo Reyes Quan Wang Moxtek, Inc.