If required, multiple ATSAS applications may smear the theoretical curves using the resolution function introduced by J. Skov Pedersen et al.. Several subroutines for data smearing were provided by J. Skov Pedersen and modified for the use in ATSAS.

The resolution file must have the following format (the numbers here describe a setting at RISOE SANS instrument):

Row Value Description
1 0.8 Effective collimation slit diameter in cm.
2 0.35 Effective sample diameter in cm.
3 300 Collimation distance in cm.
4 105 Sample-detector distance in cm.
5 3 \(\lambda\) in \(\AA\)
6 0.18 \(\sigma(\lambda)/\lambda\)
7 1.1 Pixel size in cm.
8 0.0000 Averaging error (accounted for in Pixel size).

Diagram of a SANS instrument showing the lengths required for the ill.res file

If the file is corrupted or does not exist, no smearing is performed.

An example of a resolution file is shown below. Each column corresponds to one resolution setting; the selected column number, here 1 through 5, defines the resolution setting number.

0.00001, 0.00001,   0.00001 , 0.8    , 0.8
0.00001, 0.00001,   0.00001 , 0.30   , 0.35
1100.  , 200.   ,    100.   , 300.   , 100
180.   , 125.   ,    100.   , 110.   , 100
6.0    ,  5.6   ,     1.    ,  3.22  , 6.
0.10   ,  0.09  ,    0.01   , 0.18   , 0.18
0.0001 ,  1.57  ,    0.01   , 1.1    , 1.1
0.0000 , 0.0000 ,    0.0000 , 0.0000 , 0.0000

Applications that read .res:

  • cryson - Calculates neutron scattering patterns from atomic structures.
  • monsa - Ab-initio bead modelling of multiple phases.

Applications that write .res: