NXsas¶
Status:
application definition, extends NXobject
Description:
raw, monochromatic 2-D SAS data with an area detector
This is an application definition for raw data (not processed or reduced data) from a 2-D small angle scattering instrument collected with a monochromatic beam and an area detector. It is meant to be suitable both for neutron SANS and X-ray SAXS data.
It covers all raw data from any monochromatic SAS techniques that use an area detector: SAS, WSAS, grazing incidence, GISAS
It covers all raw data from any SAS techniques that use an area detector and a monochromatic beam.
Symbols:
The symbol(s) listed here will be used below to coordinate datasets with the same shape.
nXPixel: nXPixel description
nYPixel: nYPixel description
- Groups cited:
NXcollimator, NXdata, NXdetector, NXentry, NXgeometry, NXinstrument, NXmonitor, NXmonochromator, NXsample, NXshape, NXsource
Structure:
ENTRY: (required) NXentry
@entry: (required) NX_CHAR
NeXus convention is to use
entry1,entry2, … for analysis software to locate each entrytitle: (required) NX_CHAR
start_time: (required) NX_DATE_TIME
end_time: (required) NX_DATE_TIME
definition: (required) NX_CHAR
Official NeXus NXDL schema to which this file conforms
Obligatory value:
NXsasinstrument: (required) NXinstrument
name: (required) NX_CHAR
Name of the instrument actually used to perform the experiment
source: (required) NXsource
monochromator: (required) NXmonochromator
wavelength: (required) NX_FLOAT {units=NX_WAVELENGTH}
The wavelength of the radiation
wavelength_spread: (required) NX_FLOAT
delta_lambda/lambda (\(\Delta\lambda/\lambda\)): Important for resolution calculations
collimator: (required) NXcollimator
geometry: (required) NXgeometry
detector: (required) NXdetector
data[nXPixel, nYPixel]: (required) NX_NUMBER
This is area detector data, of number of x-pixel versus number of y-pixels. Since the beam center is to be determined as a step of data reduction, it is not necessary to document or assume the position of the beam center in acquired data.
distance: (required) NX_FLOAT {units=NX_LENGTH}
The distance between detector and sample
x_pixel_size: (required) NX_FLOAT {units=NX_LENGTH}
Physical size of a pixel in x-direction
y_pixel_size: (required) NX_FLOAT {units=NX_LENGTH}
Size of a pixel in y direction
polar_angle: (required) NX_FLOAT {units=NX_ANGLE}
azimuthal_angle: (required) NX_FLOAT {units=NX_ANGLE}
rotation_angle: (required) NX_FLOAT {units=NX_ANGLE}
aequatorial_angle: (required) NX_FLOAT {units=NX_ANGLE}
beam_center_x: (required) NX_FLOAT {units=NX_LENGTH}
This is the x position where the direct beam would hit the detector. This is a length, not a pixel position, and can be outside of the actual detector.
beam_center_y: (required) NX_FLOAT {units=NX_LENGTH}
This is the y position where the direct beam would hit the detector. This is a length, not a pixel position, and can be outside of the actual detector.
sample: (required) NXsample
control: (required) NXmonitor
data: (required) NXdata
data: link (suggested target:
/NXentry/NXinstrument/NXdetector/data)
Hypertext Anchors¶
Table of hypertext anchors for all groups, fields, attributes, and links defined in this class.
