1. Combined diffraction measurements for independent determination of the 2   - error § § Presented in the National Seminar and Workshop of X-ray Diffraction 2002, 17 September 2002 at Institute of Technology 10 November Surabaya (ITS), Indonesia ¶ Currently on leave from Department of Physics, Institute of Technology 10 November Surabaya (ITS), Indonesia Suminar Pratapa & Brian O’Connor ¶ Materials Research Group, Department of Applied Physics Curtin University of Technology, Perth, WA, Australia

3. What will be presented? 1. Importance of this study 2. How to do it? 3. Results  are they good? 4. What next?

4. IMPORTANCE OF THIS STUDY Previous study using CeO 2 NIST SRM SD = specimen displacement

5. 2   -error and specimen displacemnt error - definition Both introduce systematic errors in lattice parameters. IMPORTANCE OF THIS STUDY  (  ) = 2SD/Rcos  

6. Importance of Lattice Parameters 1. Theoretical density  porosity estimates 2. Thermal expansion coefficients 3. Linear strain 4. Chemical substitution 5. etc Correction of 2   - and specimen displacement errors is absolutely essential! IMPORTANCE OF THIS STUDY

7. QUESTION IS ….. What is the 2   -error for the ITS diffractometer ¤ ? ¤ Philips X’Pert

8. HOW TO DO IT? Curtin DiffractometerITS Diffractometer Combined measurements  diffraction data for MgO ceramics were collected using both machines.

9. HOW TO DO IT? From previous study…... Current 2   -error for Curtin diffractometer is 0.0414.

10. HOW TO DO IT? Reliability of the 2   -error for Curtin diffractometer has been verified using CeO 2, Al 2 O 3 and TiO 2 NIST SRMs with accuracy level between 1:50,000 and 1:120,000 following Rietveld refinement. 1. 2   was fixed at -0.041. 2. SD was refined. The sample holder used introduced SD as much as 0.8  m on average.

11. DETERMINATION OF 2  0 -ERROR FOR ITS DIFFRACTOMETER Using 2   fixed at -0.041 of Curtin diffractometer the lattice constants of the MgO ceramics were determined using Rietveld analysis. The lattice constant for MgO ceramic 1450C-2h was used in the following: The 2   -error for ITS diffractometer is 0.0209.

12. Lattice parameter and specimen displacement for MgO ceramics calculated by  vs. cos  method (high-angle peaks only) Accuracy of 1:50,000 is achievable. Similar SD for each XRD.

13. Conclusion 1. 2   -error for ITS diffractometer has been determined with an associated measurement using Curtin diffractometer. An MgO ceramic has been used in this study. 2. Tests using MgO ceramics showed that the degree of accuracy is approximately 1:50,000. Similar specimen displacement values indicate the consistency in positioning the sample. What next? 1. 2   correction should be applied to obtain high-accuracy lattice constant values. 2. The method used in this study can be applied to obtain 2    error for other diffractometers.

14. Acknowledgements 1. AusAID for providing PhD scholarship and research travel support to ITS. 2. Curtin and ITS for providing support on this collaborative work.