Industrial Group of the BCA

January 2006 - techniques

On this page.

1. Low Angle Round Robin Update.
2. Excel SpreadSheet of EU XRPD standard Equations.

1. Low Angle Round Robin Update.

A preliminary report was presented at the Autumn Meeting. The presentation slides can be viewed on line at: http://bca.cryst.bbk.ac.uk/bca/ig/present/LARRppt/Index.htm

A preliminary look at an intensity comparison figure of merit gave the following results:

The comparisons were made using crude inspection of the raw data files to extract peak positions, heights and widths manually. It is planned to rework the data with profile fitting techniques to give more accurate assessment of the data and allow evaluation of peak shape. The only correction to the data was to normalise all intensities to 40mA and more work is required to apply corrections for slit size, counting time, goniometer radius etc.

Some problems were encountered in mounting the flexible film and with automatic specimen changers, resulting in specimen height problems. With care and the possibility of inverting the film to put the coating close to the specimen reference surface these problems can be largely overcome.

A preliminary evaluation of variability of the film coating across a sheet of the film is underway and differences have been observed. Work is ongoing to investigate variability of the film.

Some participants failed to submit data for evaluation, if they still wish to do so it will be added to the ongoing evaluation work.

A full report on this round robin will be produced in due course and be made available on the Industrial Group web pages.

Dave Taylor
January 2006

2. Excel SpreadSheet of EU XRPD standard Equations.

Some of the Equations published in the European XRPD standards have been implemented in a Microsoft Excel workbook. The workbook consists of worksheet for each of the following:

• Braggs Law
• Irradiated Length
• Divergence Angle
• Specimen Height Displacement
• Infinite Thickness
• Mass Attenuation Coefficient

You can download a copy of the 159kb Excel file. Note macros are not used in this file.