The integrated intensity I of a particular reflection measured in a TOF neutron diffraction experiment can be written as a function of the wavelength and the Bragg angle:
where h, k, l are the Miller indices designating the Bragg peaks, and the wavelength dependent correction factors are in the order given above: the incident
Parameter | Description | Command Option |
parameter file | in this file are given: reciprocal unit vectors, normalisation, absorption, sample position, etc (see below) | -P |
structure factor file | If in VITESS format .dat, each line contains: h k l Fhkl2
(see below). If in .lau format, each line contains: h k l Mult. d-space 2Theta Fhkl2. Please specify the meaning of the columns, if the structure factor file is in a different format. |
-S |
d-spacing distribution |
options 1: Lorentzian, 2: Gaussian distributions, functions
describing the d-spacing probability distribution with maximum at the nominal value (for the exact nominal value ideal reflectivity = 1., see also normalisation) |
-o |
d-spacing spread |
gives FWHM/d-spacing, the relative 'thickness' of the Ewald
sphere i.e. a small variation of the lattice constant which is same in each
direction, silicon ~ 0.0001=0.01% |
-d |
reciprocal unit vectors A, B, C [1/A] |
x,y,z components of the reciprocal unit vectors
A, B, C defined in the sample frame |
parameter file |
normalisation [arb.u.] |
normalisation factor containing for example the
number density |
parameter file |
absorption [1/cm/A] |
attenuation due to absorption within the sample
per wavelength |
parameter file |
position X,Y,Z [cm] |
coordinates of the sample centre |
parameter file |
phi(Z), chi(X), omega(again Z) [deg] |
rotation angles of sample i.e. the reciprocal unit
vectors around the Z, X and again Z axes |
parameter file |
sample geometry |
sample shape options: 'cub', 'cyl'inder (vertical),
'ball' |
parameter file |
thickness or diameter, height, width [cm] |
rectangular sample dimensions in x,y,z directions
(sample frame) |
parameter file |
output angle horizontal, vertical [deg] |
a frame rotation about the
Z axis and then a rotation about the (new)Y axis defines a new orientation
for the neutrons written to the output |
parameter file |
Column numbers for individual parameters of the look-up table | In case the structure factor file has neither the .dat (VITESS) nor .lau format, the meaning of individual columns needs to be specified so that the file can be used as structure file. | parameter file |
Scale factor | In case the structure factor file has neither the .dat (VITESS) nor .lau format, this scale factor is needed, if the (squared) structure factor is not given in barn^0.5 (barn). | parameter file |
Last modified: Wed Apr 2 18:53:44
MEST 2003, G. Zs.