initial commit

+utils/pixel_to_q.m

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+% Call function without arguments for instructions on how to use it
+
+% Filename: $RCSfile: pixel_to_q.m,v $
+%
+% $Revision: 1.1 $  $Date: 2008/06/10 17:05:14 $
+% $Author:  $
+% $Tag: $
+%
+% Description:
+% calculated momentum transfer q in inverse Angstroem from pixel numbers
+% relative to the beam center
+%
+% Dependencies: 
+% none
+%
+% history:
+%
+% June 9th 2008: 1st documented version
+
+%*-----------------------------------------------------------------------*
+%|                                                                       |
+%|  Except where otherwise noted, this work is licensed under a          |
+%|  Creative Commons Attribution-NonCommercial-ShareAlike 4.0            |
+%|  International (CC BY-NC-SA 4.0) license.                             |
+%|                                                                       |
+%|  Copyright (c) 2017 by Paul Scherrer Institute (http://www.psi.ch)    |
+%|                                                                       |
+%|       Author: CXS group, PSI                                          |
+%*-----------------------------------------------------------------------*
+% You may use this code with the following provisions:
+%
+% If the code is fully or partially redistributed, or rewritten in another
+%   computing language this notice should be included in the redistribution.
+%
+% If this code, or subfunctions or parts of it, is used for research in a 
+%   publication or if it is fully or partially rewritten for another 
+%   computing language the authors and institution should be acknowledged 
+%   in written form in the publication: “Data processing was carried out 
+%   using the “cSAXS matlab package” developed by the CXS group,
+%   Paul Scherrer Institut, Switzerland.” 
+%   Variations on the latter text can be incorporated upon discussion with 
+%   the CXS group if needed to more specifically reflect the use of the package 
+%   for the published work.
+%
+% A publication that focuses on describing features, or parameters, that
+%    are already existing in the code should be first discussed with the
+%    authors.
+%   
+% This code and subroutines are part of a continuous development, they 
+%    are provided “as they are” without guarantees or liability on part
+%    of PSI or the authors. It is the user responsibility to ensure its 
+%    proper use and the correctness of the results.
+
+function [ q_A ] = pixel_to_q( pixel, pixel_size_mm, det_dist_mm, E_keV )
+
+if (nargin ~= 4)
+    fprintf('Usage:\n');
+    fprintf('[ q_A ] = %s( pixel, pixel_size_mm, det_dist_mm, E_keV );\n',...
+        mfilename);
+    error('Wrong number of parameters, 4 expected, %d found',nargin);
+end
+
+lambda_A = 12.39852 / E_keV;
+
+q_A = 4*pi * sin( atan(pixel*pixel_size_mm/det_dist_mm) /2) / lambda_A;