3.3.1.31. NXmoderator¶
Status:
base class, extends NXobject
Description:
A neutron moderator
Symbols:
No symbol table
- Groups cited:
NXdata, NXgeometry, NXlog, NXoff_geometry, NXtransformations
Structure:
@default: (optional) NX_CHAR
Declares which child group contains a path leading to a NXdata group.
It is recommended (as of NIAC2014) to use this attribute to help define the path to the default dataset to be plotted. See https://www.nexusformat.org/2014_How_to_find_default_data.html for a summary of the discussion.
distance: (optional) NX_FLOAT {units=NX_LENGTH}
Effective distance as seen by measuring radiation. Note, it is recommended to use NXtransformations instead.
type: (optional) NX_CHAR
Any of these values:
H20
D20
Liquid H2
Liquid CH4
Liquid D2
Solid D2
C
Solid CH4
Solid H2poison_depth: (optional) NX_FLOAT {units=NX_LENGTH}
coupled: (optional) NX_BOOLEAN
whether the moderator is coupled
coupling_material: (optional) NX_CHAR
The material used for coupling. Usually Cd.
poison_material: (optional) NX_CHAR
Any of these values:
Gd|Cdtemperature: (optional) NX_FLOAT {units=NX_TEMPERATURE}
average/nominal moderator temperature
depends_on: (optional) NX_CHAR
NeXus positions components by applying a set of translations and rotations to apply to the component starting from 0, 0, 0. The order of these operations is critical and forms what NeXus calls a dependency chain. The depends_on field defines the path to the top most operation of the dependency chain or the string “.” if located in the origin. Usually these operations are stored in a NXtransformations group. But NeXus allows them to be stored anywhere.
The reference point of the moderator is its center in the x and y axis. The reference point on the z axis is the surface of the moderator pointing towards the source (the negative part of the z axis).
GEOMETRY: (optional) NXgeometry
DEPRECATED: Use the field depends_on and NXtransformations to position the moderator and NXoff_geometry to describe its shape instead
“Engineering” position of moderator
temperature_log: (optional) NXlog
log file of moderator temperature
pulse_shape: (optional) NXdata
moderator pulse shape
OFF_GEOMETRY: (optional) NXoff_geometry
This group describes the shape of the moderator
TRANSFORMATIONS: (optional) NXtransformations
This is the group recommended for holding the chain of translation and rotation operations necessary to position the component within the instrument. The dependency chain may however traverse similar groups in other component groups.
Hypertext Anchors¶
List of hypertext anchors for all groups, fields, attributes, and links defined in this class.