def computeKf(Ei, E, Q, log):
ki = Conv.e2k(Ei);
log.write( "* ki=%s\n" % (ki,) )
kiv = np.array([ki, 0, 0])
kfv = kiv - Q
log.write( "* vectors ki=%s, kf=%s\n" % (kiv, kfv) )
Ef = Ei - E
# ** Verify the momentum and energy transfers **
log.write( "These two numbers should be very close:\n")
log.write( " %s\n" % (Ei-Conv.k2e(np.linalg.norm(kfv)),) )
log.write( " %s\n" % (Ei-Ef,) )
assert np.isclose(Ef, Conv.k2e(np.linalg.norm(kfv)))
log.write( " Ei=%s, Ef=%s\n" % (Ei,Ef) )
return kfv, Ef
def Eresidual(xtalori, hkl, Etarget, angles, Ei):
"""compute residual of energy transfer
This method compute a series of psi angle and corresponding residual
(E - Etarget).
We only need to simulate crystal orientation where the residual
is close to zero.
"""
from mcni.utils import conversion as conv
ki = conv.e2k(Ei)
kiv = np.array([ki,0,0])
r = np.zeros((len(angles), 2))
for i, psi in enumerate(angles):
xtalori.psi = psi / 180. * np.pi
hkl2cartesian = xtalori.hkl2cartesian_mat()
# cart2hkl = xtalori.cartesian2hkl_mat()
Qcart = np.dot(hkl, hkl2cartesian)
# print hkl, np.dot(Qcart, cart2hkl)
# print Qcart
kfv = kiv - Qcart
kf = np.linalg.norm(kfv)
Ef = conv.k2e(kf)
E = Ei - Ef
r[i] = psi, E-Etarget
continue
return r
def calcIQE(uc, omega, pols, Qpoints, Q_bins, E_bins):
"""main part of IQE calculation. missing several corrections
"""
N = len(Qpoints)
Qmag = np.linalg.norm(Qpoints, axis=-1)
from ..atomic_scattering import AtomicScattering
symbols = [a.element for a in uc]
bs = [AtomicScattering(s).b() for s in symbols]
masses = [AtomicScattering(s).mass for s in symbols]
positions = np.array([a.xyz for a in uc])
bovermass = np.array(bs) / np.sqrt(masses)
#
import tqdm
bins = Q_bins, E_bins
# in reciprocal units
hkls = np.dot(Qpoints, uc.lattice.base.T) / (2 * np.pi)
I = 0
nQ, nbr, natoms, three = pols.shape
assert three == 3
good = omega > 0
for ibr in tqdm.tqdm(range(nbr)):
good1 = good[:, ibr]
Qmag_good = Qmag[good1]
omega_good = omega[good1, ibr]
Q_cart = Qpoints[good1, :]
good_hkls = hkls[good1, :]
#
exp_Q_dot_d = np.exp(1j * np.dot(good_hkls, positions.T) * 2 *
np.pi) # nQ, natoms
pols1 = pols[good1, ibr, :, :] # nQ, natoms, 3
Q_dot_pol = np.sum(np.transpose(pols1, (1, 0, 2)) * Q_cart,
axis=-1).T # nQ, natoms
#
F = np.sum(exp_Q_dot_d * Q_dot_pol * bovermass, axis=-1) # nQ
M = np.abs(F)**2 / omega_good # nQ
I1, Qbb, Ebb = np.histogram2d(Qmag_good,
omega_good,
bins=bins,
weights=M)
I = I + I1
continue
from mcni.utils import conversion
I *= conversion.k2e(1.) # canceling unit: hbar^2Q^2/2M/(hbar*omega)
# M is |b_d/sqrt(M_d)exp(iQ.d)(Q.e)|^2/omega
# At this moment M (and I) is using b in fm. change it to barn
I /= 100
# Need to consider the density of the Q points and the volume of the Q space sampled.
uc_vol = uc.lattice.volume
ruc_vol = (2 * np.pi)**3 / uc_vol
max_Q = Q_bins[-1]
I *= 1. / N * 4. / 3 * np.pi * max_Q**3 / ruc_vol
return Qbb, Ebb, I
def test(self):
"wrap IQE_monitor"
from mcstas2 import componentfactory
factory = componentfactory( category, componentname )
Ei = 70
Qmin=0; Qmax=13.; nQ=130
Emin=-50; Emax=50.; nE=100
component = factory(
'component',
Ei=Ei,
Qmin=Qmin, Qmax=Qmax, nQ=nQ,
Emin=Emin, Emax=Emax, nE=nE,
max_angle_out_of_plane=30, min_angle_out_of_plane=-30,
max_angle_in_plane=120, min_angle_in_plane=-30,
)
import mcni
from mcni.utils import conversion as C
neutrons = mcni.neutron_buffer( nQ*nE )
import numpy as N
count = 0
for Q in N.arange(Qmin, Qmax, (Qmax-Qmin)/nQ):
for E in N.arange(Emin,Emax,(Emax-Emin)/nE):
Ef = Ei-E
cosphi = (Ei+Ef-C.k2e(Q))/(2*N.sqrt(Ei)*N.sqrt(Ef))
vf = C.e2v(Ef)
vfz = vf*cosphi
sinphi = N.sqrt(1-cosphi*cosphi)
vfx = vf*sinphi
neutrons[count] = mcni.neutron(r=(0,0,0), v=(vfx,0,vfz), time = 0, prob = 1)
count += 1
continue
component.process( neutrons )
from mcstas2.pyre_support._component_interfaces.monitors.IQE_monitor import get_histogram
hist = get_histogram(component)
if interactive:
from histogram.plotter import defaultPlotter
defaultPlotter.plot(hist)
return
def test1(self):
'kernel orientation'
# source
from mcni.components.MonochromaticSource import MonochromaticSource
import mcni, numpy as np
Ei = 100
from mcni.utils import conversion as Conv
ki = Conv.e2k(Ei)
vi = Conv.e2v(Ei)
Qdir = np.array([np.sqrt(3)/2, 0, -1./2])
Q = Qdir * 2
kf = np.array([0,0,ki]) - Q
Ef = Conv.k2e(np.linalg.norm(kf))
E = Ei-Ef
dv = Qdir * Conv.k2v(Q)
vf = np.array([0,0,vi]) - dv
# print ki, Q, kf
# print Ei, Ef, E
neutron = mcni.neutron(r=(0,0,-1), v=(0,0,vi), prob=1)
source = MonochromaticSource('s', neutron, dx=0.001, dy=0.001, dE=0)
# sample
from mccomponents.sample import samplecomponent
scatterer = samplecomponent('sa', 'cyl/sampleassembly.xml' )
# incident
N = 1000
neutrons = mcni.neutron_buffer(N)
neutrons = source.process(neutrons)
# print neutrons
# scatter
scatterer.process(neutrons)
# print neutrons
self.assertEqual(len(neutrons), N)
for neutron in neutrons:
np.allclose(neutron.state.velocity, vf)
self.assert_(neutron.probability > 0)
continue
return
def qikr(wl_0=1., center_wl=13.05):
"""
@param wl_min: wavelength at the lower end of the bandwidth
"""
running_length = 0
k0 = 2*np.pi/wl_0
e0_max = conversion.k2e(k0)
kmin = 2*np.pi/40.0
e0_min = conversion.k2e(kmin)
instrument = mcvine.instrument()
# Source - includes straight tube
beam_width = 0.0266
tube_length = 1.0
mod = mcvine.components.sources.SNS_source_r1('moderator',
S_filename='./SNS-STS-ROT1-15_sp.dat',
width=beam_width, height=0.0266, dist=tube_length,
xw=beam_width, yh=0.0327, Emin=0, Emax=e0_max)
instrument.append(mod, position=(0,0,0))
#running_length += 0.001
# Source Tube ##################################################################
#tube = mcvine.components.optics.Guide_channeled(name='source_tube',
# w1=beam_width, h1=0.0266, w2=beam_width, h2=0.0327,
# l=tube_length, mx=0, my=0)
running_length += tube_length + 0.0001
# Ballistic Guide 1 #############################################################
# From 100 cm to 620 cm
guide_1_length = 5.2
guide1 = mcvine.components.optics.Guide_channeled(name='guide_1',
w1=beam_width, h1=0.0327, w2=beam_width, h2=0.0642,
l=guide_1_length, mx=5, my=5)
instrument.append(guide1, position=(0,0,running_length))
print ("Ballistic guide 1: %s m" % running_length)
running_length += guide_1_length + 0.0001
# T0 chopper ###################################################################
# From 620 cm to 664.8 cm
#t0_chopper = mcvine.components.optics.Vertical_T0(name='t0chopper', len=0.448,
# w1=beam_width, w2=beam_width, nu=120, delta=0.0, tc=0., ymin=-.045, ymax=0.045)
#instrument.append(t0_chopper, position=(0,0,6.2))
running_length += 0.448
# Ballistic Guide 2 #############################################################
# From 664.8 cm to 714.8 cm
guide_2_length = 0.5
guide2 = mcvine.components.optics.Guide_channeled(name='guide_2',
w1=beam_width, h1=0.067, w2=beam_width, h2=0.07,
l=guide_2_length, mx=5, my=5)
instrument.append(guide2, position=(0,0,running_length))
print ("Ballistic guide 2: %s m" % running_length)
running_length += guide_2_length + 0.0001
# Bandwidth chopper ############################################################
# From 714.8 cm to 722.1 cm
instrument.append(mcvine.components.monitors.NeutronToStorage('save_pre', 'beam_pre_chopper.neutrons'),
position=(0,0,running_length))
running_length += 0.0001
b_chopper_length = 0.073
b_chopper_dist = running_length + b_chopper_length/2.0 # center of chopper
print ("Bandwidth chopper: %s m" % b_chopper_dist)
aperture_bottom = 0.2689
aperture_top = 0.33949
radius_to_beam = 0.30390
open_angle = 111.964
kmid = 2*np.pi/center_wl
v = conversion.k2v(kmid)
delay = b_chopper_dist/v
disk_chopper = mcvine.components.optics.DiskChopper_v2(name='band_chopper',
yheight=aperture_top-aperture_bottom,
nslit=1,
radius=aperture_top,
theta_0=open_angle,
delay=delay, nu=7.5)
running_length += 0.0001
instrument.append(disk_chopper, position=(0,0, b_chopper_dist))
instrument.append(mcvine.components.monitors.NeutronToStorage('save_post', 'beam_post_chopper.neutrons'),
position=(0,0,running_length))
running_length += b_chopper_length + 0.0001
# Ballistic Guide 3 #############################################################
# From 722.1 cm to 1264 cm
guide_3_length = 5.419
guide3 = mcvine.components.optics.Guide_channeled(name='guide_3',
w1=beam_width, h1=0.07, w2=beam_width, h2=0.1033,
l=guide_3_length, mx=5, my=5)
instrument.append(guide3, position=(0,0,running_length))
running_length += guide_3_length + 0.0001
# Tapered guide #################################################################
# From 1264 cm to 1599 cm
guide_4_length = 3.35
guide4 = mcvine.components.optics.Guide_channeled(name='guide_4',
w1=beam_width, h1=0.1033, w2=beam_width, h2=0.02,
l=guide_4_length, mx=5, my=5)
instrument.append(guide4, position=(0,0,running_length))
running_length += guide_4_length + 0.0001
instrument.append(mcvine.components.monitors.NeutronToStorage('save', 'beam.neutrons'),
position=(0,0,running_length))
running_length += 0.0001
print("End of instrument: %s m" % running_length)
return instrument
