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# Differences

This shows you the differences between two versions of the page.

fixed_incident_beam_absorption [2010/10/19 00:04] rowlesmr |
fixed_incident_beam_absorption [2020/07/16 11:29] |
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- | ====== Fixed_Incident_Beam_Thick_Sample_Absorption ====== | ||

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

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

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- | [1] Rowles, M. R. & Madsen, I. C. 2010, 'Whole-Pattern Profile Fitting of Powder Diffraction Data Collected in Parallel-Beam Flat-Plate Asymmetric Reflection Geometry', Journal of Applied Crystallography, vol. 43, no. 3, pp. 632-634. | ||

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- | Contributor: Matthew Rowles | ||

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- | Thick Sample absorption correction for fixed incident beam geometry. There is a typo in the delta function in the original reference. It's correct here.\\ | ||

- | Ref: Masson, O., Guiebretière, R. & Dauger, A. (1996). J. Appl. Cryst. 29, 540-546. | ||

- | <code topas>macro Fixed_Incident_Beam_Thick_Sample_Absorption { FIBTSA } | ||

- | macro FIBTSA(alpha_v, mu_v) { FIBTSA(,alpha_v,,mu_v) } | ||

- | macro FIBTSA(alpha, alpha_v, mu, mu_v) | ||

- | { | ||

- | #m_argu mu ''in cm^-1 | ||

- | #m_argu alpha ''in degrees | ||

- | If_Prm_Eqn_Rpt(mu, mu_v, min 3 max 500) | ||

- | If_Prm_Eqn_Rpt(alpha, alpha_v, min 0.0001 max 90) | ||

- | exp_conv_const = Ln(0.001) (1/((CeV(mu,mu_v) Rs / 10) ((1/Tan(2 Th - CeV(alpha,alpha_v) Deg)) + Tan(Th)))) Rad; | ||

- | ''^ the Ln(0.001) is because of the definition of the exp func in topas -- see the manual. | ||

- | ''^ the /10 is in there because Rs is in mm and mu is in cm^-1 | ||

- | }</code> | ||