Source code for PyMca5.PyMcaPhysics.xrf.IncoherentScattering

#/*##########################################################################
#
# The PyMca X-Ray Fluorescence Toolkit
#
# Copyright (c) 2004-2014 European Synchrotron Radiation Facility
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# This file is part of the PyMca X-ray Fluorescence Toolkit developed at
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__author__ = "V.A. Sole - ESRF Data Analysis"
__contact__ = "sole@esrf.fr"
__license__ = "MIT"
__copyright__ = "European Synchrotron Radiation Facility, Grenoble, France"
import os
import numpy
from PyMca5.PyMcaIO import ConfigDict
from PyMca5 import PyMcaDataDir

ElementList= ['H','He','Li','Be','B','C','N','O','F','Ne',
              'Na','Mg','Al','Si','P','S','Cl','Ar','K','Ca','Sc','Ti','V','Cr','Mn','Fe','Co','Ni','Cu','Zn',
     'Ga','Ge','As','Se','Br','Kr',
     'Rb','Sr','Y','Zr','Nb','Mo','Tc','Ru','Rh','Pd','Ag','Cd',
     'In','Sn','Sb','Te','I','Xe','Cs','Ba','La','Ce','Pr','Nd',
     'Pm','Sm','Eu','Gd','Tb','Dy','Ho','Er','Tm','Yb','Lu','Hf',
     'Ta','W','Re','Os','Ir','Pt','Au','Hg','Tl','Pb','Bi','Po','At',
     'Rn','Fr','Ra','Ac','Th','Pa','U','Np','Pu','Am','Cm','Bk','Cf',
     'Es','Fm','Md','No','Lr','Rf','Db','Sg','Bh','Hs','Mt']

dirmod = PyMcaDataDir.PYMCA_DATA_DIR
ffile   = os.path.join(dirmod,"attdata")
ffile   = os.path.join(ffile,"incoh.dict")
if not os.path.exists(ffile):
    #freeze does bad things with the path ...
    dirmod = os.path.dirname(dirmod)
    ffile = os.path.join(dirmod, "attdata")
    ffile = os.path.join(ffile, "incoh.dict")
    if not os.path.exists(ffile):
        if dirmod.lower().endswith(".zip"):
            dirmod = os.path.dirname(dirmod)
            ffile = os.path.join(dirmod,"attdata")
            ffile = os.path.join(ffile, "incoh.dict")
    if not os.path.exists(ffile):
        print("Cannot find file ", ffile)
        raise IOError("Cannot find file %s" % ffile)

COEFFICIENTS = ConfigDict.ConfigDict()
COEFFICIENTS.read(ffile)
xvalues = COEFFICIENTS['ISCADT']['XSVAL']
svalues = numpy.reshape(COEFFICIENTS['ISCADT']['SCATF'], (100, len(xvalues)))
#svalues = COEFFICIENTS['ISCADT']['SCATF']
#print svalues[100:110]
KEVTOANG = 12.39852000
R0 = 2.82E-13 #electron radius in cm

[docs]def getZ(ele): if ele in ElementList: return float(ElementList.index(ele)+1) else: return None
[docs]def getElementComptonFormFactor(ele, theta, energy): return getElementIncoherentScatteringFunction(ele, theta, energy)
[docs]def getComptonScatteringEnergy(energy, theta): return energy/(1.0 + \ (energy/511.) * (1 - numpy.cos(theta*(numpy.pi / 180.0))))
[docs]def getElementIncoherentScatteringFunction(ele, theta, energy): """ Usage: getIncoherentScatteringFunction(ele,theta, energy): ele - Element theta - Scattering angle in degrees energy- Photon Energy in keV This routine calculates the incoherent scattering function in electron units an interpolation to EGS4 tabulation of S(x,Z)/Z """ if ele in ElementList: z = getZ(ele) else: z = float(ele) wavelength = KEVTOANG / energy sinhalftheta = numpy.sin(theta * (numpy.pi / 360.0)) #Hubbel just give this term x = sinhalftheta / wavelength #print "x old = ",x e = energy/511.0 #Fajardo uses: x = x * numpy.sqrt(1.0 + e* (e+2.0)* pow(sinhalftheta, 2))/ \ (1.0 + 2.0 * e * pow(sinhalftheta, 2)) #print "x new = ",x ilow = 0 ihigh = 44 i = 22 while (ihigh - ilow) > 1: if x < xvalues[i]:ihigh = i else:ilow =i i = int((ihigh+ilow)/2) if z > 100: if ihigh == ilow: value = svalues[int(99),ilow] else: A = (x - xvalues[ilow])/(xvalues[ihigh]-xvalues[ilow]) value = ((1.0 - A ) * svalues[int(99),ilow] + \ A * svalues[int(99),ihigh]) value = value * (z/100.) else: if ihigh == ilow: value = svalues[int(z-1),ilow] else: A = (x - xvalues[ilow])/(xvalues[ihigh]-xvalues[ilow]) value = ((1.0 - A ) * svalues[int(z-1),ilow] + \ A * svalues[int(z-1),ihigh]) return value
[docs]def getElementComptonDifferentialCrossSection(ele, theta, energy, p1=None): if p1 is None:p1=0.0 if (p1 > 1.0) or (p1 < -1): raise ValueError(\ "Invalid degree of linear polarization respect to the scattering plane") thetasin2 = pow(numpy.sin(theta * numpy.pi / 180.0), 2) thetacos = numpy.cos(theta * numpy.pi/180.0) e = energy/(1.0 + (energy/511.) * (1.0 - thetacos)) return 0.5 * ((e/energy) + (energy/e) + (p1-1.0) * thetasin2) * \ pow(R0*(e/energy)*getElementIncoherentScatteringFunction(ele, theta, energy),2)
getElementIncoherentDifferentialCrossSection=\ getElementComptonDifferentialCrossSection if __name__ == "__main__": import sys if len(sys.argv) > 3: ele = sys.argv[1] theta = float(sys.argv[2]) energy= float(sys.argv[3]) print(getElementComptonFormFactor(ele, theta, energy)) else: print("Usage:") print("python IncoherentScatteringFunction.py Element Theta(deg) Energy(kev)")