def scatteringdata(elem, e1, e2, de, fname):
en_array = energy_array(e1, e2, de)
mu_total = xraydb.mu_elam(elem, en_array, kind='total')
mu_photo = xraydb.mu_elam(elem, en_array, kind='photo')
mu_incoh = xraydb.mu_elam(elem, en_array, kind='incoh')
mu_coher = xraydb.mu_elam(elem, en_array, kind='coh')
header = [
' X-ray Atomic Scattering Cross-Sections from xrayweb %s ' %
time.ctime(),
' Element : %s ' % elem, ' Column.1: Energy (eV)',
' Column.2: mu_total (cm^2/gr)',
' Column.3: mu_photo (cm^2/gr) # Photo-electric',
' Column.4: mu_coher (cm^2/gr) # Rayleigh',
' Column.5: mu_incoh (cm^2/gr) # Compton'
]
arr_names = [
'energy ', 'mu_total ', 'mu_photo ', 'mu_coher ',
'mu_incoh '
]
arrays = [en_array, mu_total, mu_photo, mu_coher, mu_incoh]
atz = xraydb.atomic_number(elem)
if atz < 93:
header.extend([
' Column.6: f1 (electrons/atom) # real resonant',
' Column.7: f2 (electrons/atom) # imag resonant'
])
arr_names.extend(['f1 ', 'f2 '])
arrays.extend([
xraydb.f1_chantler(elem, en_array),
xraydb.f2_chantler(elem, en_array)
])
txt = make_asciifile(header, arr_names, arrays)
return Response(txt, mimetype='text/plain')
def test_f1f2_chantler():
en = np.linspace(10000, 15000, 51)
f1 = np.array([-5.97, -6.08, -6.20, -6.33, -6.46, -6.60, -6.75, -6.91,
-7.09, -7.28, -7.49, -7.72, -7.99, -8.28, -8.64, -9.06,
-9.60, -10.33, -11.54, -15.14, -12.27, -10.64, -9.78,
-9.18, -8.76, -8.43, -8.18, -7.98, -7.83, -7.73, -7.66,
-7.64, -7.66, -7.73, -7.87, -8.13, -8.58, -9.91, -9.18,
-8.19, -7.73, -7.46, -7.36, -7.61, -7.43, -6.61, -6.13,
-5.77, -5.46, -5.20, -4.96 ])
f2 = np.array([5.12, 5.04, 4.96, 4.87, 4.80, 4.72, 4.64, 4.57, 4.50,
4.43, 4.37, 4.30, 4.24, 4.18, 4.12, 4.06, 4.01, 3.97,
3.93, 4.15, 9.94, 9.83, 9.70, 9.57, 9.43, 9.30, 9.17,
9.05, 8.92, 8.80, 8.69, 8.57, 8.46, 8.35, 8.25, 8.14,
8.05, 8.02, 10.94, 10.83, 10.71, 10.59, 10.47, 10.39,
11.75, 11.67, 11.56, 11.44, 11.33, 11.21, 11.10])
assert_allclose(f1, f1_chantler('Au', en), rtol=0.01)
assert_allclose(f2, f2_chantler('Au', en), rtol=0.01)
assert_allclose(f1, chantler_data('Au', en, 'f1'), rtol=0.01)
assert_allclose(f2, chantler_data('Au', en, 'f2'), rtol=0.01)
def test_f1f2_chantler_mo():
en = np.linspace(1000, 500000, 501)
f1 = f1_chantler('Mo', en)
assert (len(f1) > 400)
def scattering(elem=None, e1='1000', e2='50000', de='50'):
f1f2_plot = mu_plot = {}
if len(request.form) != 0:
elem = request.form.get('elem', 'None')
e1 = request.form.get('e1', e1)
e2 = request.form.get('e2', e2)
de = request.form.get('de', de)
if elem not in (None, 'None', ''):
atz = xraydb.atomic_number(elem)
en_array = energy_array(e1, e2, de)
mu_total = xraydb.mu_elam(elem, en_array, kind='total')
mu_photo = xraydb.mu_elam(elem, en_array, kind='photo')
mu_incoh = xraydb.mu_elam(elem, en_array, kind='incoh')
mu_coher = xraydb.mu_elam(elem, en_array, kind='coh')
yrange = [
-0.25 + min(-1.8, np.log10(mu_photo.min() + 1.e-5),
np.log10(mu_incoh.min() + 1.e-5),
np.log10(mu_coher.min() + 1.e-5)),
0.75 + np.log10(mu_total.max() + 1.e-5)
]
mu_plot = make_plot(en_array,
mu_total,
'Mass Attenuation for %s' % elem,
elem,
ytitle='mu/rho (cm^2/gr)',
xtitle='Energy (eV)',
xlog_scale=False,
ylog_scale=True,
yrange=yrange,
yformat='.2f',
y1label='Total',
y2=mu_photo,
y2label='Photo-electric',
y3=mu_incoh,
y3label='Incoherent',
y4=mu_coher,
y4label='Coherent')
if atz < 93:
try:
f1 = xraydb.f1_chantler(elem, en_array)
except:
f1 = xraydb.f1_chantler(elem, en_array, smoothing=1)
f2 = xraydb.f2_chantler(elem, en_array)
f1f2_plot = make_plot(en_array,
f1,
'Resonant Scattering factors for %s' % elem,
elem,
ytitle='f1, f2 (electrons/atom)',
xtitle='Energy (eV)',
xlog_scale=False,
ylog_scale=False,
y2=f2,
y1label='f1',
y2label='f2')
return render_template('scattering.html',
elem=elem,
e1=e1,
e2=e2,
de=int(de),
f1f2_plot=f1f2_plot,
mu_plot=mu_plot,
materials_dict=materials_dict)
def mback(energy, mu=None, group=None, z=None, edge='K', e0=None, pre1=None, pre2=-50,
norm1=100, norm2=None, order=3, leexiang=False, tables='chantler', fit_erfc=False,
return_f1=False, _larch=None):
"""
Match mu(E) data for tabulated f''(E) using the MBACK algorithm and,
optionally, the Lee & Xiang extension
Arguments
----------
energy: array of x-ray energies, in eV.
mu: array of mu(E).
group: output group.
z: atomic number of the absorber.
edge: x-ray absorption edge (default 'K')
e0: edge energy, in eV. If None, it will be determined here.
pre1: low E range (relative to e0) for pre-edge region.
pre2: high E range (relative to e0) for pre-edge region.
norm1: low E range (relative to e0) for post-edge region.
norm2: high E range (relative to e0) for post-edge region.
order: order of the legendre polynomial for normalization.
(default=3, min=0, max=5).
leexiang: boolean (default False) to use the Lee & Xiang extension.
tables: tabulated scattering factors: 'chantler' [deprecated]
fit_erfc: boolean (default False) to fit parameters of error function.
return_f1: boolean (default False) to include the f1 array in the group.
Returns
-------
None
The following attributes will be written to the output group:
group.f2: tabulated f2(E).
group.f1: tabulated f1(E) (if 'return_f1' is True).
group.fpp: mback atched spectrum.
group.edge_step: edge step of spectrum.
group.norm: normalized spectrum.
group.mback_params: group of parameters for the minimization.
Notes:
Chantler tables is now used, with Cromer-Liberman no longer supported.
References:
* MBACK (Weng, Waldo, Penner-Hahn): http://dx.doi.org/10.1086/303711
* Lee and Xiang: http://dx.doi.org/10.1088/0004-637X/702/2/970
* Cromer-Liberman: http://dx.doi.org/10.1063/1.1674266
* Chantler: http://dx.doi.org/10.1063/1.555974
"""
order = max(min(order, MAXORDER), 0)
### implement the First Argument Group convention
energy, mu, group = parse_group_args(energy, members=('energy', 'mu'),
defaults=(mu,), group=group,
fcn_name='mback')
if len(energy.shape) > 1:
energy = energy.squeeze()
if len(mu.shape) > 1:
mu = mu.squeeze()
if _larch is not None:
group = set_xafsGroup(group, _larch=_larch)
energy = remove_dups(energy)
if e0 is None or e0 < energy[1] or e0 > energy[-2]:
e0 = find_e0(energy, mu, group=group)
print(e0)
ie0 = index_nearest(energy, e0)
e0 = energy[ie0]
pre1_input = pre1
norm2_input = norm2
if pre1 is None: pre1 = min(energy) - e0
if norm2 is None: norm2 = max(energy) - e0
if norm2 < 0: norm2 = max(energy) - e0 - norm2
pre1 = max(pre1, (min(energy) - e0))
norm2 = min(norm2, (max(energy) - e0))
if pre1 > pre2:
pre1, pre2 = pre2, pre1
if norm1 > norm2:
norm1, norm2 = norm2, norm1
p1 = index_of(energy, pre1+e0)
p2 = index_nearest(energy, pre2+e0)
n1 = index_nearest(energy, norm1+e0)
n2 = index_of(energy, norm2+e0)
if p2 - p1 < 2:
p2 = min(len(energy), p1 + 2)
if n2 - n1 < 2:
p2 = min(len(energy), p1 + 2)
## theta is a boolean array indicating the
## energy values considered for the fit.
## theta=1 for included values, theta=0 for excluded values.
theta = np.zeros_like(energy, dtype='int')
theta[p1:(p2+1)] = 1
theta[n1:(n2+1)] = 1
## weights for the pre- and post-edge regions, as defined in the MBACK paper (?)
weight = np.ones_like(energy, dtype=float)
weight[p1:(p2+1)] = np.sqrt(np.sum(weight[p1:(p2+1)]))
weight[n1:(n2+1)] = np.sqrt(np.sum(weight[n1:(n2+1)]))
## get the f'' function from CL or Chantler
f1 = f1_chantler(z, energy)
f2 = f2_chantler(z, energy)
group.f2 = f2
if return_f1:
group.f1 = f1
em = find_xray_line(z, edge).energy # erfc centroid
params = Parameters()
params.add(name='s', value=1.0, vary=True) # scale of data
params.add(name='xi', value=50.0, vary=False, min=0) # width of erfc
params.add(name='a', value=0.0, vary=False) # amplitude of erfc
if fit_erfc:
params['a'].vary = True
params['a'].value = 0.5
params['xi'].vary = True
for i in range(order+1): # polynomial coefficients
params.add(name='c%d' % i, value=0, vary=True)
out = minimize(match_f2, params, method='leastsq',
gtol=1.e-5, ftol=1.e-5, xtol=1.e-5, epsfcn=1.e-5,
kws = dict(en=energy, mu=mu, f2=f2, e0=e0, em=em,
order=order, weight=weight, theta=theta, leexiang=leexiang))
opars = out.params.valuesdict()
eoff = energy - e0
norm_function = opars['a']*erfc((energy-em)/opars['xi']) + opars['c0']
for i in range(order):
attr = 'c%d' % (i + 1)
if attr in opars:
norm_function += opars[attr]* eoff**(i + 1)
group.e0 = e0
group.fpp = opars['s']*mu - norm_function
# calculate edge step and normalization from f2 + norm_function
pre_f2 = preedge(energy, group.f2+norm_function, e0=e0, pre1=pre1,
pre2=pre2, norm1=norm1, norm2=norm2, nnorm=2, nvict=0)
group.edge_step = pre_f2['edge_step'] / opars['s']
group.norm = (opars['s']*mu - pre_f2['pre_edge']) / pre_f2['edge_step']
group.mback_details = Group(params=opars, pre_f2=pre_f2,
f2_scaled=opars['s']*f2,
norm_function=norm_function)
