def _calc_alpha(self):
"""
Calc alpha, ie incidence angle or angle btwn
-1*k_in (which is parallel to lab-y) and the
plane perp to the reference vector n.
"""
nm = self.nm
ki = num.array([0., -1., 0.])
alpha = arcsind(num.dot(nm, ki))
self.pangles['alpha'] = alpha
def tth(self,hkl,lam=None):
"""
Calculate 2Theta for given [h,k,l] and wavelength
Notes:
------
If lam is None the default lambda will be used (Cu Ka1)
If you pass in lam, this will change the default for
subsequent calls
"""
if lam != None: self.lam = float(lam)
d = self.d(hkl)
if d == 0.: return 0.
r = self.lam/(2.*d)
if num.fabs(r) > 1.0:
r = r/num.fabs(r)
tth = 2.*arcsind(r)
return tth
def tth(self,hkl,lam=None):
"""
Calculate 2Theta for given [h,k,l] and wavelength
Notes:
------
If lam is None the default lambda will be used (Cu Ka1)
If you pass in lam, this will change the default for
subsequent calls
"""
if lam != None: self.lam = float(lam)
d = self.d(hkl)
if d == 0.: return 0.
r = self.lam/(2.*d)
if num.fabs(r) > 1.0:
r = r/num.fabs(r)
tth = 2.*arcsind(r)
return tth
def _calc_beta(self):
"""
Calc beta, ie exit angle, or angle btwn k_r and the
plane perp to the reference vector n
Notes:
------
beta = arcsind(2*sind(tth/2)*cosd(tau)-sind(alpha))
"""
# calc normalized kr
#delta = self.angles['delta']
#nu = self.angles['nu']
#kr = num.array([sind(delta),
# cosd(nu)*cosd(delta),
# sind(nu)*cosd(delta)])
nm = self.nm
kr = self.kr / cartesian_mag(self.kr)
beta = arcsind(num.dot(nm, kr))
self.pangles['beta'] = beta
def _spec_or_angles(angles, calc_kappa=False):
"""
Angles defined by spec for the OR's.
See specfile.py
Notes:
------
Assume the following.
If parsing angles from the P array:
(generally shouldnt need this since angles
are tagged with motor labels on read)
angles = P
if psic:
angles = angles[0:5]
elif kappa fourc
angles = [angles[0:3], angles[8], angles[7]]
If parsing angles from the G array:
angles = G[x:y]
where x:y depend on whether you are
parsing out or0 or or1.
See spec_G below
We then assume the following:
del = angles[0]
eta = angles[1]
chi = angles[2]
phi = angles[3]
nu = angles[4]
mu = angles[5]
Note: calc kappa, keta and kphi
kap_alp = 50.031;
keta = eta - asin(-tan(chi/2)/tan(kap_alp))
kphi = phi - asin(-tan(chi/2)/tan(kap_alp))
kappa = asin(sin(chi/2)/sin(kap_alp))
"""
# angles from spec
delta = angles[0]
eta = angles[1]
chi = angles[2]
phi = angles[3]
nu = angles[4]
mu = angles[5]
# kappa angles
if calc_kappa:
kap_alp = 50.031
keta = eta - arcsind(-tand(chi / 2.) / tand(kap_alp))
kphi = phi - arcsind(-tand(chi / 2.) / tand(kap_alp))
kappa = asind(sind(chi / 2.) / sind(kap_alp))
return {
'phi': phi,
'chi': chi,
'eta': eta,
'mu': mu,
'delta': delta,
'nu': nu,
'keta': keta,
'kphi': kphi,
'kappa': kappa
}
else:
return {
'phi': phi,
'chi': chi,
'eta': eta,
'mu': mu,
'delta': delta,
'nu': nu
}