Dear Wahyu, As well as the points that David has pointed out, the background could be due to fluorescence from elements in your sample. For example iron fluoresces under excitation from copper x-rays and so if you have access to another wavelength / source then it may be more successfull. Or if you have the facility for a secondary monochromator in your setup?
Regards Ross Colman David Lee wrote: > I would suggest that you do the background refinement with GSAS. Try using Expgui, a graphical > interface to gsas written by Brian Toby, to select background points and do a background fit. > There are excellent tutorials on doing this available at: http://www.ncnr.nist.gov/xtal/software/expgui/ > > Also, you need to find out why your background is so high and rough. Do you have > other phases present? Is your material not fully crystallized? Is your sample > (if a powder) ground finely enough? Is your sample surface smooth and flat? > > Good Luck, > > David Lee, Ph.D. > DTLee Scientific, llc > http://www.dtlee.com > 614-562-6230 > > On May 19, 2009, at 6:16 AM, wahyu bambang wrote: > >> Dear all rietvelder, >> >> Please give me a suggestion about my problem. >> I want to do quantitative analysis using GSAS, however my diffraction >> pattern has very high and rough background which makes me difficult to >> do preliminary qualitative works to determine the available phases. >> >> Is it alright if I substract the background and refine it a little >> first using another refinement software before I go through GSAS? >> >> I really appreciate your kindness to answer. >> >> regards, >> >> wahyu >> > > -- ________________________________ Ross Colman G19 Christopher Ingold Laboratories University College London Department of Chemistry 20 Gordon Street London WC1H 0AJ Phone: +44 (0)20 7679 4636 Internal: 24636 Email: ross.col...@ucl.ac.uk <mailto:ross.col...@ucl.ac.uk>
