I am new to Fullprof program and I would like to ask you one basic question. How do I know the initial coefficient value of background polynomial function if I set Nba=0 for my neutron powder diffraction?
1 - See the corresponding background formula 2 - see your pattern 3 - detect the angle where the background is minimum and use this value for BKPOS, then use the minimal intensity as the first value of the 6 coefficients of the polynomial (the first coefficient is a constant, independent of the angle). 4 - Set the 5 other coefficients at 0. With 6 values like : 115 0 0 0 0 0 the background will be a flat one with height 115 counts. 5 - if you had already a refinement made by using a manual estimated background, then fix all parameters already refined and let the first four background coefficients to be refined. 6 - depending on how far is going your pattern to large angle (>>90), add a few refinement cycles with all 6 background coefficients free. 7 - set all your previously fixed parameters to vary again.
8 - And see other techniques like Fourier filtering : http://www.mail-archive.com/[EMAIL PROTECTED]/msg01765.html
Best wishes,
Armel
