Peak profile: TCH p-v (npr=7 in FullProf).
(1) For lab source (Beam horizontal size: 12mm and detector type: Lynx eye or scintillation)
Condition (a) Goniometer radius = 280mm
Soller slits: 2.3 degree (in both, source & detector arms)
Is it necessary to have Soller slit width in mm or degree?
Condition (b) Goniometer radius = 280mm
Soller slits: 2.5 degree in detector arm only,
in source arm no soller slits are used.
- How to use these numbers to calculate S_L and D_L for Bragg Brentano Geometry?
- Are these numbers remains same if Parallel beam geometry is used instead of Bragg Brentano?
- Is calculation of S_L and D_L are affected by choice of detector?
(2) Synchrotron source (with Mar345 image plate detector) Debye-Schrerrer Geometry:
Sample to detector distance ~ 150 mm. (no slits)
Mar345 slits: 0.3 mm (Horizontal and vertical directions before capillary).
Capillary diameter: ~ 0.1 mm.
Vertical focusing using Pre-Mirror at a distance 12600 mm away from sample (capillary) position.
Horizontal focusing using second bendable mirror of DCM at a distance 8200 mm away from sample (capillary) position.
Yes, you have to calculate them (with the fit tool in Winplotr) and leave.them fixed in Fullprof.
In Winplotr, you can start with a value of 0.01, for both values. Refine first one (S_L for example), and then the other. Normally the range of those values is 0-0.03, more or less. In the case that Winplotr doesn't refine the values, change them manually until you have a good fit with your data. And then you'll have S_L and D_L for Fullprof (fixed).
Indeoendantly of the machine (lab source or synchrotron), I calcularé the valves the same way:
Open the newest version of Winplotr. Zoom in (one of) the first peaks of the pattern. The ones at lower angles are more susceptible to the assymetry.
Then you'll find the button FIT in Winplotr and you will be able to fit the peak,calculating S_L and D_L. I normally fit the peak position, Fwhm and it's deviation (clicked by default) and also W and Eta0. And of course, S_L and D_L. At the end it is a least squares fit. You'll see it in every cycle.
Hope it works for you
Dear Dr. Francisco, thank you for your help. I have tried this option, but it does not refine S_L and D_L (even after manually clicking), value is zero always.
I want to calculate these numbers using instrument parameters and kept fix during refinement. But there is little detail in Fullprof manual about there units and calculation.
Yes, you have to calculate them (with the fit tool in Winplotr) and leave.them fixed in Fullprof.
In Winplotr, you can start with a value of 0.01, for both values. Refine first one (S_L for example), and then the other. Normally the range of those values is 0-0.03, more or less. In the case that Winplotr doesn't refine the values, change them manually until you have a good fit with your data. And then you'll have S_L and D_L for Fullprof (fixed).
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