[ Identification | Description | Input parameters | Links ]

The Monitor_Sqw Component

This component is a Sqw Monitor that records the dynamic structure factor S(q,w) from a scattering location, seen from a detector location.

Identification

• Site:
• Author: Emmanuel Farhi
• Origin: ILL
• Date: 31 jan 2014.

Description

This component is a specialized Monitor_nD variation, which records the S(q,w)
scattering law. It accepts about the same parameters as the Monitor_nD, but makes
use of the 'q' and 'w' user variables. The neutrons are restored in their previous
state after neing detected (restore_neutron=1).

The monitor records the intensity as a function of q=kf-ki and w=Ef-Ei were the
'f' refers to the component location, and the 'i' refers to the component located
at 'index' relative to the component location.

The component uses automatic limits, and is thus not recommended with MPI/multiprocessing.
In this case, the limits should be set manually, e.g. user1=q and user2=w
options="user1 limits=[0 10] bins=100, user2 limits=[-50 50] bins=200"

A usage example is for instance:
COMPONENT sample = Isotropic_Sqw(...)

COMPONENT sqw = Monitor_Sqw(index=-1, radius=2, yheight=2, bins=128)

This component can be used to generate dynamic structure factors comvolved with
the instrument response, and compare with molecular dynamics results (using e.g. nMoldyn).
The incoming beam (e.g. at the sample) must be monochromatic.

Input parameters

Parameters in boldface are required; the others are optional.

Name	Unit	Description	Default
user3			FLT_MAX
xwidth	m	Width of detector.	0
yheight	m	Height of detector.	0
zdepth	m	Thickness of detector (z).	0
xmin	m	Lower x bound of opening	0
xmax	m	Upper x bound of opening	0
ymin	m	Lower y bound of opening	0
ymax	m	Upper y bound of opening	0
zmin	m	Lower z bound of opening	0
zmax	m	Upper z bound of opening	0
radius	m	Radius of sphere/banana shape monitor	0
bins	1	Number of bins to force for all variables. Use 'bins' keyword in 'options' for heterogeneous bins	0
min			-1e40
max			1e40
index	1	Index of the component where scattering occurs with respect to the location of the Monitor_Sqw location in the instrument description. The index is usually negative, and should point to e.g. a Isotropic_Sqw, , PowderN, or Single_crystal instance. index=-1 for the previous component.	-1
options	str	String that specifies the configuration of the monitor The general syntax is "[x] options..." (see Descr.).	0
filename	str	Output file name. If not set an automatic file name is used.	0
geometry	str	Name of an OFF file to specify a complex geometry detector	0
username3			0
nowritefile	1	If set, monitor will skip writing to disk	0

AT (	,	,		) RELATIVE		Generate
ROTATED (	,	,		) RELATIVE

Links

• Source code for Monitor_Sqw.comp.
• Monitor_nD
• Test_Monitor_Sqw
• nMoldyn

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[ Identification | Description | Input parameters | Links ]

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

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Last Modified: Tuesday, 16-Apr-2024 20:05:22 CEST