[ Identification | Description | Input parameters | Links ]

# The `Samples_Incoherent` Instrument

This instrument allows to compare incoherent scattering from different McStas sample components.

## Identification

- Site: Tests_samples
- Author: Peter Willendrup, Erik Knudsen, Aziz Aziz Daoud-aladine
- Origin: RISOE
- Date: August 14th, 2007

## Description

    This instrument allows to compare incoherent scattering from different McStas
    sample components:

    * PowderN
    Single_crystal
    Isotropic_sqw
    Incoherent

    Examples:

    Compare incoherent scattering from all sample comps, beamstop in place.

    mcrun Samples_Incoherent -d Some_directory -N5 SAMPLE=1,5 STOP=1

    Compare incoherent scattering and direct beam attenuation for PowderN, Single_crystal
    and Isotroic_sqw:

    mcrun Samples_Incoherent -d Some_other_directory -N4 SAMPLE=2,5 STOP=0

    Have a closer look of direct beam attentuation for PowderN, Single_crystal
    and Isotroic_sqw (has the side-effect that back-scattered neutrons are absorbed):

    mcrun Samples_Incoherent -d Some_third_directory -N4 SAMPLE=2,5 STOP=0 DB=1

    The sample type selection is:
    box:      1=Vanadium
    2=PowderN
    3=Single_Crystal
    4=Isotropic_Sqw
    5=Incoherent
    10=Isotropic_Sqw with V.lau
    cube.off: 6=PowderN,
    7=Single_Crystal
    8=Isotropic_Sqw
    9=Incoherent

## Input parameters

Parameters in boldface are required; the others are optional.

Name | Unit | Description | Default
L_min | AA | Minimum wavelength of neutrons | 0.5
L_max | AA | Maximum wavelength of neutrons | 7
SAMPLE |  | Sample choice, 1:Incoherent, 2:PowderN, 3:Single_crystal, 4:Isotropic_Sqw, 5:Incoherent with multiple scattering, 6:PowderN with OFF geometry, 7:Single_crystal with OFF geometry, 8:Isotropic_Sqw with OFF geometry, 9:Incoherent with OFF geometry, 10:Isotropic_Sqw with .laz input | 1
STOP | 1 | Beamstop inserted? (Needed in case of comparison between V and SX/sqw). | 0
Order | 1 | Maximum order of multiple scattering in SX/sqw | 0
INC | barns | Incoherent scattering cross section | 5.08
ABS | barns | Absorption cross section | 5.08
DB | 1 | Direct Beam monitor inserted? (Side-effect: absorbs 'backscattered' neutrons). | 0
ISISFACE | string | ISIS moderator face to look at | "hydrogen"

## Links

- Source code for `Samples_Incoherent.instr`.
- Validation of Single_crystal is now in progress!

[ Identification | Description | Input parameters | Links ]