3.3.1.14. NXdetector_channel

Status:

base class, extends NXobject

Description:

Description and metadata for a single channel from a multi-channel detector. ...

Description and metadata for a single channel from a multi-channel detector.

Given an NXdata group linked as part of an NXdetector group that has an axis with named channels (see the example in NXdata), the NXdetector will have a series of NXdetector_channel groups, one for each channel, named CHANNELNAME_channel.

Example, given these axes in the NXdata group:

@axes = ["image_id", "channel", ".", "."]

And this list of channels in the NXdata group:

channel = ["threshold_1", "threshold_2", "difference"]

The NXdetector group would have three NXdetector_channel groups:

detector:NXdetector
  ...
  threshold_1_channel:NXdetector_channel
    threshold_energy = float
    flatfield = float[i, j]
    pixel_mask = uint[i, j]
    flatfield_applied = bool
    pixel_mask_applied = bool
  threshold_2_channel:NXdetector_channel
    threshold_energy = float
    flatfield = float[i, j]
    pixel_mask = uint[i, j]
    flatfield_applied = bool
    pixel_mask_applied = bool
  difference_channel:NXdetector_channel
    threshold_energy = float[2]

Symbols:

These symbols will be used below to illustrate the coordination of the rank and ...

These symbols will be used below to illustrate the coordination of the rank and sizes of datasets and the preferred ordering of the dimensions. Each of these are optional (so the rank of the datasets will vary according to the situation) and the general ordering principle is slowest to fastest. The type of each dimension should follow the order of scan points, detector output (e.g. pixels), then time-of-flight (i.e. spectroscopy, spectrometry). Note that the output of a detector is not limited to single values (0D), lists (1D) and images (2D), but three or higher dimensional arrays can be produced by a detector at each trigger.

dataRank: Rank of the data field associated with this detector

nP: number of scan points

i: number of detector pixels in the slowest direction

j: number of detector pixels in the second slowest direction

k: number of detector pixels in the third slowest direction

Groups cited:

none

Structure:

threshold_energy: (optional) NX_FLOAT {units=NX_ENERGY}

Energy at which a photon will be recorded

flatfield_applied: (optional) NX_BOOLEAN

True when the flat field correction has been applied in the ...

True when the flat field correction has been applied in the electronics, false otherwise.

flatfield: (optional) NX_NUMBER (Rank: dataRank, Dimensions: [i, j, [k]])

Response of each pixel given a constant input

flatfield_errors: (optional) NX_FLOAT (Rank: 2, Dimensions: [i, j])

Errors of the flat field correction data. ...

Errors of the flat field correction data. The form flatfield_error is deprecated.

pixel_mask_applied: (optional) NX_BOOLEAN

True when the pixel mask correction has been applied in the ...

True when the pixel mask correction has been applied in the electronics, false otherwise.

pixel_mask: (optional) NX_INT (Rank: dataRank, Dimensions: [., i, j, [k]])

Custom pixel mask for this channel. May include nP as the first dimension for ...

Custom pixel mask for this channel. May include nP as the first dimension for masks that vary for each scan point.

saturation_value: (optional) NX_NUMBER

The value at which the detector goes into saturation. ...

The value at which the detector goes into saturation. Especially common to CCD detectors, the data is known to be invalid above this value.

For example, given a saturation_value and an underload_value, the valid pixels are those less than or equal to the saturation_value and greater than or equal to the underload_value.

The precise type should match the type of the data.

underload_value: (optional) NX_NUMBER

The lowest value at which pixels for this detector would be reasonably ...

The lowest value at which pixels for this detector would be reasonably measured. The data is known to be invalid below this value.

For example, given a saturation_value and an underload_value, the valid pixels are those less than or equal to the saturation_value and greater than or equal to the underload_value.

The precise type should match the type of the data.

Hypertext Anchors

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

NXDL Source:

https://github.com/nexusformat/definitions/blob/main/base_classes/NXdetector_channel.nxdl.xml