[ 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:

V_sample
PowderN
Single_crystal
Isotropic_sqw
Incoherent

Examples:

Compare incoherent scattering from all sample comps, beamstop in place:
(V_multiples=0: V_sample algo identical to PowderN algo - NO multiples
V_multiples: V_sample performs crude estimate for multiple scattering)

mcrun Samples_Incoherent -d Some_directory -N5 SAMPLE=1,5 STOP=1 V_multiples=0

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.laz
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
STOP	1	Beamstop inserted? (Needed in case of comparison between V and SX/sqw).	0
V_multiples	1	Use crude estimate for multiple scattering in V_sample?	1
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!

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[ Identification | Description | Input parameters | Links ]

Generated on 2024-01-03 11:47:43

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Last Modified: Wednesday, 03-Jan-2024 19:59:11 CET