About McStas Download Documentation 
[ Identification  Description  Input parameters  Output parameters  Links ] The
Henrich Frielinghaus
Several benchmark SANS samples are defined in this routine. The first ones are analytically defined. Higher numbers are forseen for tables.
In principle, the exact definitions can be changed freely  inside this code.
The consideration of all parameters as a routine parameter would be too much for the general purpose.
The user might decide to make single parameters routine parameters.
For the scattering simulation a high fraction of neutron paths is directed to the scattering (exact fraction is sc_aim).
The remaining paths are used for the transmitted beams. The absolute intensities are treated accordingly, and the pparameter is set accordingly.
For the scattering probability, the integral of the scattering function between Q = 0.0001 and 1.0 AA1 is calculated.
This is used in terms of transmisson, and of course for the scattering probability.
In this way, multiple scattering processes could be treated as well.
The typical SANS range was considered to be between 0.0001 and 1.0 AA1.
This means that the scattered neutrons are equally distributed in this range on logarithmic Qscales.
The Qparameters can be changed still inside the code, if needed.

Name  Unit  Description  Default 

xwidth  m  width of sample volume  0.01 
yheight  m  height of sample volume  0.01 
zthick  m  thickness of sample volume  0.001 
model    model no., real variable will be rounded. negative numbers interpreted as model #0, too large as #18. case 0  no coherent scattering case 1  polymer with Mw = 2.000g/mol case 2  polymer with Mw = 1.000.000g/mol case 3  microemulsion case 4  wormlike micelle case 5  sphere, R = 25 AA case 6  sphere, R = 500 AA case 7  polymer blend case 8  diblock copolymer case 9  multilamellar vesicles case 10  logarithmically spaced series of sharp peaks case 11  logarithmically spaced series of sharp delta peaks !!!!!! ... case 15  sphere, R = 150 AA case 18 free  1.0 
dsdw_inc  0.02  
sc_aim  0.97  
sans_aim  0.95  
singlesp  0.0 
SANS_benchmark2.comp
.
[ Identification  Description  Input parameters  Output parameters  Links ]
Generated automatically by McDoc, Peter Willendrup <peter.willendrup@risoe.dk> / Tue May 26 13:03:59 2020