neutronpy.instrument.TripleAxisInstrument.resolution_convolution

TripleAxisInstrument.resolution_convolution(sqw, pref, nargout, hkle, METHOD='fix', ACCURACY=None, p=None, seed=None)

Numerically calculate the convolution of a user-defined cross-section function with the resolution function for a 3-axis neutron scattering experiment.

Parameters:

sqw : func

User-supplied “fast” model cross section.

pref : func

User-supplied “slow” cross section prefactor and background function.

nargout : int

Number of arguments returned by the pref function

hkle : tup

Tuple of H, K, L, and W, specifying the wave vector and energy transfers at which the convolution is to be calculated (i.e. define $mathbf{Q}_0$). H, K, and L are given in reciprocal lattice units and W in meV.

EXP : obj

Instrument object containing all information on experimental setup.

METHOD : str

Specifies which 4D-integration method to use. ‘fix’ (Default): sample the cross section on a fixed grid of points uniformly distributed $phi$-space. 2*ACCURACY[0]+1 points are sampled along $phi_1$, $phi_2$, and $phi_3$, and 2*ACCURACY[1]+1 along $phi_4$ (vertical direction). ‘mc’: 4D Monte Carlo integration. The cross section is sampled in 1000*ACCURACY randomly chosen points, uniformly distributed in $phi$-space.

ACCURACY : array(2) or int

Determines the number of sampling points in the integration.

p : list

A parameter that is passed on, without change to sqw and pref.

Returns:

conv : array

Calculated value of the cross section, folded with the resolution function at the given $mathbf{Q}_0$

Notes

Translated from ResLib 3.4c, originally authored by A. Zheludev, 1999-2007, Oak Ridge National Laboratory