50 lines
1.8 KiB
Python
50 lines
1.8 KiB
Python
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from __future__ import print_function,division
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import numpy as np
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import os
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def xrayAttLenght(*args,**kw):
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from periodictable import xsf
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n = xsf.index_of_refraction(*args,**kw)
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if not "wavelength" in kw:
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wavelength = 12.398/np.asarray(kw["energy"])
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else:
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wavelength = np.asarray(kw["wavelength"])
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attenuation_length = np.abs( (wavelength*1e-10)/ (4*np.pi*np.imag(n)) )
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return attenuation_length
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def xrayFluo(atom,density,energy=7.,length=30.,I0=1e10,\
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det_radius=1.,det_dist=10.,det_material="Si",det_thick=300,verbose=True):
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""" compound: anything periodictable would understand
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density: in mM
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length: sample length in um
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energy: in keV, could be array
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"""
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import periodictable
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from periodictable import xsf
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wavelength = 12.398/energy
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atom = periodictable.__dict__[atom]
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# 1e3 -> from mM to M
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# 1e3 -> from L to cm3
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# so 1 mM = 1e-3M/L = 1e-6 M/cm3
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density_g_cm3 = density*1e-6*atom.mass
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n = xsf.index_of_refraction(atom,density=density_g_cm3,wavelength=wavelength)
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attenuation_length = xrayAttLenght( atom,density=density_g_cm3,energy=energy )
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# um-> m: 1e-6
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fraction_absorbed = 1.-np.exp(-length*1e-6/attenuation_length)
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if verbose:
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print("Fraction of x-ray photons absorbed by the sample:",fraction_absorbed)
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## detector ##
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det_area = np.pi*det_radius**2
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det_solid_angle = det_area/(4*np.pi*det_dist**2)
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if verbose:
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print("Detector fraction of solid angle:",det_solid_angle)
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det_att_len = xrayAttLenght(det_material,wavelength=atom.K_alpha)
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det_abs = 1-np.exp(-det_thick*1e-6/det_att_len)
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if verbose:
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print("Detector efficiency (assuming E fluo = E_K_alpha):",det_abs)
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eff = fraction_absorbed*det_solid_angle*det_abs
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if verbose:
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print("Overall intensity (as ratio to incoming one):",eff)
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return eff
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