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 }