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Fixed_Incident_Beam_Thick_Sample_Correction

This macro is part of a collection that are used to properly model the effects of a flat plat sample with a fixed angle incident beam.

There is a nice overview of their application in [1]. Individual references are given for each macro.

Contributor: Matthew Rowles

This macro models the intensity and sample displacement.

A container macro required to correct for peak intensity and peak shift for thick samples when in flat plate, fixed incident beam geometry. If you are using a parallel incident beam, then you would also probably want to use Fixed_Incident_Beam_Footprint_Correction_With_Mixing to correct for the peak profile change over 2theta. Also, depending on the sample, you may also want to correct for absorption by using Fixed_Incident_Beam_Thick_Sample_Absorption

macro Fixed_Incident_Beam_Thick_Sample_Correction { FIBTSC } 
macro FIBTSC(alpha_v) { FIBTSC(, alpha_v,,0) }    
macro FIBTSC(alpha_v, sd_v) { FIBTSC(, alpha_v,, sd_v) }
macro FIBTSC(alpha, alpha_v, sd, sd_v)
{
    Fixed_Incident_Beam_Thick_Sample_Intensity_Correction(alpha, alpha_v)
    Fixed_Incident_Beam_Peak_Position_Correction(alpha, alpha_v, sd, sd_v)
}

Scales the intensity for a thick sample in fixed incident beam geometry. Must be used in conjunction with Fixed_Incident_Beam_Peak_Position_Correction if you want to model sample displacement.
Ref: Toraya, H., Huang, T. C. & Wu, Y. (1993). J. Appl. Cryst. 26, 774-777.

macro Fixed_Incident_Beam_Thick_Sample_Intensity_Correction (alpha, alpha_v)
{
   #m_argu alpha ''angle of the incident beam to the flat plate in degrees
   If_Prm_Eqn_Rpt(alpha, alpha_v, min 0.0001 max 90)
 
   scale_pks = 
      IF (2 Th) < CeV(alpha, alpha_v) Deg THEN 
         0                                 
      ELSE
         2 / (1 + (Sin(CeV(alpha, alpha_v) Deg) / Sin(2 Th - CeV(alpha, alpha_v) Deg)))
      ENDIF;
}

Models sample displacement as required for a flat plate in fixed incident beam geometry. Valid for both thick and thin samples.
Ref: Masson, O., Guiebretière, R. & Dauger, A. (1996). J. Appl. Cryst. 29, 540-546.

macro Fixed_Incident_Beam_Peak_Position_Correction (alpha, alpha_v, sd, sd_v)
{
   #m_argu alpha ''angle of the flat plate in degrees
   #m_argu sd    ''displacement of the sample in mm (technically, the same dimension as the radius...)
   If_Prm_Eqn_Rpt(alpha, alpha_v, min 0.0001 max 90)
   If_Prm_Eqn_Rpt(sd, sd_v, min -2 max 2)
 
   th2_offset = 
      IF CeV(sd, sd_v) == 0 THEN 
         0
      ELSE
         -Rad (CeV(sd, sd_v) Sin(2 Th)) / (Rs Sin(CeV(alpha, alpha_v) Deg))
      ENDIF;
}

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