base class, extends NXobject


Logical grouping of detectors. When used, describes a group of detectors.

Each detector is represented as an NXdetector with its own detector data array. Each detector data array may be further decomposed into array sections by use of NXdetector_module groups. Detectors can be grouped logically together using NXdetector_group. Groups can be further grouped hierarchically in a single NXdetector_group (for example, if there are multiple detectors at an endstation or multiple endstations at a facility). Alternatively, multiple NXdetector_groups can be provided.

The groups are defined hierarchically, with names given in the group_names field, unique identifying indices given in the field group_index, and the level in the hierarchy given in the group_parent field. For example if an x-ray detector group, DET, consists of four detectors in a rectangular array:


We could have:

group_names: ["DET", "DTL", "DTR", "DLL", "DLR"]
group_index: [1, 2, 3, 4, 5]
group_parent:  [-1, 1, 1, 1, 1]


No symbol table

Groups cited:



@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.

group_names: (optional) NX_CHAR

An array of the names of the detectors given in NXdetector groups or the names of hierarchical groupings of detectors given as names of NXdetector_group groups or in NXdetector_group group_names and group_parent fields as having children.

group_index: (optional) NX_INT (Rank: 1, Dimensions: [i])

An array of unique identifiers for detectors or groupings of detectors.

Each ID is a unique ID for the corresponding detector or group named in the field group_names. The IDs are positive integers starting with 1.

group_parent: (optional) NX_INT (Rank: same as field group_index, Dimensions: same as field group_index)

An array of the hierarchical levels of the parents of detectors or groupings of detectors.

A top-level grouping has parent level -1.

group_type: (optional) NX_INT (Rank: same as field group_index, Dimensions: same as field group_index)

Code number for group type, e.g. bank=1, tube=2 etc.

Hypertext Anchors

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.

NXDL Source: