.. auto-generated by script ../../../../utils/nxdl2rst.py from the NXDL source NXmx.nxdl.xml
.. index::
! NXmx (application definition)
! mx (application definition)
see: mx (application definition); NXmx
.. _NXmx:
====
NXmx
====
**Status**:
application definition, extends :ref:`NXobject`
**Description**:
functional application definition for macromolecular crystallography
**Symbols**:
These symbols will be used below to coordinate datasets
with the same shape. Most MX x-ray detectors will produce
two-dimensional images. Some will produce three-dimensional
images, using one of the indices to select a detector element.
**dataRank**: rank of the ``data`` field
**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**:
:ref:`NXattenuator`, :ref:`NXbeam`, :ref:`NXcollection`, :ref:`NXdata`, :ref:`NXdetector_group`, :ref:`NXdetector_module`, :ref:`NXdetector`, :ref:`NXentry`, :ref:`NXgeometry`, :ref:`NXinstrument`, :ref:`NXnote`, :ref:`NXsample`, :ref:`NXsource`, :ref:`NXtransformations`
.. index:: NXentry (base class); used in application definition, NXdata (base class); used in application definition, NXsample (base class); used in application definition, NXtransformations (base class); used in application definition, NXinstrument (base class); used in application definition, NXattenuator (base class); used in application definition, NXdetector_group (base class); used in application definition, NXdetector (base class); used in application definition, NXcollection (base class); used in application definition, NXdetector_module (base class); used in application definition, NXbeam (base class); used in application definition, NXsource (base class); used in application definition, NXnote (base class); used in application definition, NXgeometry (base class); used in application definition
**Structure**:
**(entry)**: (required) :ref:`NXentry`
.. index:: title (field)
**title**: (optional) :ref:`NX_CHAR <NX_CHAR>`
.. index:: start_time (field)
**start_time**: (required) :ref:`NX_DATE_TIME <NX_DATE_TIME>`
ISO 8601 time/date of the first data point collected in UTC,
using the Z suffix to avoid confusion with local time.
Note that the time zone of the beamline should be provided in
NXentry/NXinstrument/time_zone.
.. index:: end_time (field)
**end_time**: (optional) :ref:`NX_DATE_TIME <NX_DATE_TIME>`
ISO 8601 time/date of the last data point collected in UTC,
using the Z suffix to avoid confusion with local time.
Note that the time zone of the beamline should be provided in
NXentry/NXinstrument/time_zone. This field should only be
filled when the value is accurately observed. If the data
collection aborts or otherwise prevents accurate recording of
the end_time, this field should be omitted.
.. index:: end_time_estimated (field)
**end_time_estimated**: (required) :ref:`NX_DATE_TIME <NX_DATE_TIME>`
ISO 8601 time/date of the last data point collected in UTC,
using the Z suffix to avoid confusion with local time.
Note that the time zone of the beamline should be provided in
NXentry/NXinstrument/time_zone. This field may be filled
with a value estimated before an observed value is avilable.
.. index:: definition (field)
**definition**: (required) :ref:`NX_CHAR <NX_CHAR>`
NeXus NXDL schema to which this file conforms
Obligatory value: ``NXmx``
**(data)**: (required) :ref:`NXdata`
.. index:: data (field)
**data[np, i, j, k]**: (recommended) :ref:`NX_NUMBER <NX_NUMBER>`
For a dimension-2 detector, the rank of the data array will be 3.
For a dimension-3 detector, the rank of the data array will be 4.
This allows for the introduction of the frame number as the
first index.
**(sample)**: (required) :ref:`NXsample`
.. index:: name (field)
**name**: (required) :ref:`NX_CHAR <NX_CHAR>`
Descriptive name of sample
.. index:: depends_on (field)
**depends_on**: (required) :ref:`NX_CHAR <NX_CHAR>`
This is a requirement to describe for any scan experiment.
The axis on which the sample position depends may be stored
anywhere, but is normally stored in the NXtransformations
group within the NXsample group.
If there is no goniometer, e.g. with a jet, depends_on
should be set to "."
.. index:: temperature (field)
**temperature**: (optional) :ref:`NX_CHAR <NX_CHAR>` {units=\ :ref:`NX_TEMPERATURE <NX_TEMPERATURE>`}
**(transformations)**: (required) :ref:`NXtransformations`
This is the recommended location for sample goniometer
and other related axes.
This is a requirement to describe for any scan experiment.
The reason it is optional is mainly to accommodate XFEL
single shot exposures.
Use of the depends_on field and the NXtransformations group is
strongly recommended. As noted above this should be an absolute
requirement to have for any scan experiment.
The reason it is optional is mainly to accommodate XFEL
single shot exposures.
**(instrument)**: (required) :ref:`NXinstrument`
.. index:: name (field)
**name**: (required) :ref:`NX_CHAR <NX_CHAR>`
Name of instrument
.. index:: short_name (field attribute)
**@short_name**: (required) :ref:`NX_CHAR <NX_CHAR>`
short name for instrument, perhaps the acronym
.. index:: time_zone (field)
**time_zone**: (recommended) :ref:`NX_DATE_TIME <NX_DATE_TIME>`
ISO 8601 time_zone offset from UTC
**(attenuator)**: (optional) :ref:`NXattenuator`
.. index:: attenuator_transmission (field)
**attenuator_transmission**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_UNITLESS <NX_UNITLESS>`}
**(detector_group)**: (recommended) :ref:`NXdetector_group`
Optional logical grouping of detector elements.
Each detector element is represented as an NXdetector group
with its own detector data array. Each detector data array
may be further decomposed into array sections by use of
NXdetector_module groups. The names are given in the
group names field.
The groups are defined hierarchically, with names given
in the group_names field, unique identifiing 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, DET, consists of four elements in a rectangular array::
DTL DTR
DLL DLR
We could have::
group_names: ["DET", "DTL", "DTR", "DLL", "DLR"]
group_index: [1, 2, 3, 4, 5]
group_parent: [-1, 1, 1, 1, 1]
.. index:: group_names (field)
**group_names**: (required) :ref:`NX_CHAR <NX_CHAR>`
An array of the names of the detector elements or hierarchical
groupings of detector elements.
Specified in the base classes as comma separated list of names,
but new code should use an array of names as quoted strings.
.. index:: group_index (field)
**group_index[i]**: (required) :ref:`NX_INT <NX_INT>`
An array of unique indices for detector elements or groupings
of detector elements.
Each element is a unique ID for the corresponding group named
in the field group_names. The IDs are positive integers starting
with 1.
.. index:: group_parent (field)
**group_parent[group_index]**: (required) :ref:`NX_INT <NX_INT>`
An array of the hierarchical levels of the parents of detector
elements or groupings of detector elements.
A top-level element or grouping has parent level -1
**(detector)**: (required) :ref:`NXdetector`
Normally the detector group will have the name ``detector``.
However, in the case of multiple detector elements, each element
needs a uniquely named NXdetector group.
.. index:: depends_on (field)
**depends_on**: (required) :ref:`NX_CHAR <NX_CHAR>`
NeXus path to the detector positioner axis that most directly
supports the detector.
.. index:: data (field)
**data[np, i, j, k]**: (recommended) :ref:`NX_NUMBER <NX_NUMBER>`
For a dimension-2 detector, the rank of the data array will be 3.
For a dimension-3 detector, the rank of the data array will be 4.
This allows for the introduction of the frame number as the
first index.
.. index:: description (field)
**description**: (recommended) :ref:`NX_CHAR <NX_CHAR>`
name/manufacturer/model/etc. information
.. index:: time_per_channel (field)
**time_per_channel**: (optional) :ref:`NX_CHAR <NX_CHAR>` {units=\ :ref:`NX_TIME <NX_TIME>`}
todo: define more clearly
.. index:: distance (field)
**distance**: (recommended) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
Distance from the sample to the beam center.
Normally this value is for guidance only, the proper
geometry can be found following the depends_on axis chain,
But in appropriate cases where the dectector distance
to the sample is observable independent of the axis
chain, that may take precedence over the axis chain
calculation.
.. index:: distance_derived (field)
**distance_derived**: (recommended) :ref:`NX_BOOLEAN <NX_BOOLEAN>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
Boolean to indicate if the distance is a derived, rather than
a primary observation. If distance_derived true or is not specified,
the distance is assumed to be derived from delector axis
specifications.
.. index:: dead_time (field)
**dead_time**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_TIME <NX_TIME>`}
Detector dead time
.. index:: count_time (field)
**count_time**: (recommended) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_TIME <NX_TIME>`}
Elapsed actual counting time
.. index:: beam_center_derived (field)
**beam_center_derived**: (optional) :ref:`NX_BOOLEAN <NX_BOOLEAN>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
Boolean to indicate if the distance is a derived, rather than
a primary observation. If true or not provided, that value of
beam_center_derived is assumed to be true
.. index:: beam_center_x (field)
**beam_center_x**: (recommended) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
This is the x position where the direct beam would hit the
detector. This is a length and can be outside of the actual
detector. The length can be in physical units or pixels as
documented by the units attribute. Normally, this should
be derived from the axis chain, but the direct specification
may take precendence if it is not a derived quantity.
.. index:: beam_center_y (field)
**beam_center_y**: (recommended) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
This is the y position where the direct beam would hit the
detector. This is a length and can be outside of the actual
detector. The length can be in physical units or pixels as
documented by the units attribute. Normally, this should
be derived from the axis chain, but the direct specification
may take precendence if it is not a derived quantity.
.. index:: angular_calibration_applied (field)
**angular_calibration_applied**: (optional) :ref:`NX_BOOLEAN <NX_BOOLEAN>`
True when the angular calibration has been applied in the
electronics, false otherwise.
.. index:: angular_calibration (field)
**angular_calibration[i, j, k]**: (optional) :ref:`NX_FLOAT <NX_FLOAT>`
Angular calibration data.
.. index:: flatfield_applied (field)
**flatfield_applied**: (optional) :ref:`NX_BOOLEAN <NX_BOOLEAN>`
True when the flat field correction has been applied in the
electronics, false otherwise.
.. index:: flatfield (field)
**flatfield[i, j, k]**: (optional) :ref:`NX_FLOAT <NX_FLOAT>`
Flat field correction data. If provided, it is recommended
that is be compressed
.. index:: flatfield_error (field)
**flatfield_error[i, j, k]**: (optional) :ref:`NX_FLOAT <NX_FLOAT>`
Errors of the flat field correction data. If provided, it is recommended
that it be compressed
.. index:: pixel_mask_applied (field)
**pixel_mask_applied**: (optional) :ref:`NX_BOOLEAN <NX_BOOLEAN>`
True when the pixel mask correction has been applied in the
electronics, false otherwise.
.. index:: pixel_mask (field)
**pixel_mask[i, j]**: (recommended) :ref:`NX_INT <NX_INT>`
The 32-bit pixel mask for the detector. Can be either one mask
for the whole dataset (i.e. an array with indices i, j) or
each frame can have its own mask (in which case it would be
an array with indices np, i, j).
Contains a bit field
for each pixel to signal dead,
blind or high or otherwise unwanted
or undesirable pixels.
They have the following meaning:
* bit 0: gap (pixel with no sensor)
* bit 1: dead
* bit 2: under responding
* bit 3: over responding
* bit 4: noisy
* bit 5: -undefined-
* bit 6: pixel is part of a cluster of problematic pixels (bit set in addition to others)
* bit 7: -undefined-
* bit 8: user defined mask (e.g. around beamstop)
* bits 9-30: -undefined-
* bit 31: virtual pixel (corner pixel with interpolated value)
Normal data analysis software would
not take pixels into account
when a bit in (mask & 0x0000FFFF) is
set. Tag bit in the upper
two bytes would indicate special pixel
properties that normally
would not be a sole reason to reject the
intensity value (unless
lower bits are set.
If the full bit depths is not required, providing a
mask with fewer bits is permissible.
If needed, additional pixel masks can be specified by
including additional entries named pixel_mask_N, where
N is an integer. For example, a general bad pixel mask
could be specified in pixel_mask that indicates noisy
and dead pixels, and an additional pixel mask from
experiment-specific shadowing could be specified in
pixel_mask_2. The cumulative mask is the bitwise OR
of pixel_mask and any pixel_mask_N entries.
If provided, it is recommended that it be compressed
.. index:: countrate_correction_applied (field)
**countrate_correction_applied**: (optional) :ref:`NX_BOOLEAN <NX_BOOLEAN>`
True when a count-rate correction has already been applied in
the data recorded here, false otherwise.
.. index:: bit_depth_readout (field)
**bit_depth_readout**: (recommended) :ref:`NX_INT <NX_INT>`
How many bits the electronics record per pixel.
.. index:: detector_readout_time (field)
**detector_readout_time**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_TIME <NX_TIME>`}
Time it takes to read the detector (typically milliseconds).
This is important to know for time resolved experiments.
.. index:: frame_time (field)
**frame_time**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_TIME <NX_TIME>`}
This is time for each frame. This is exposure_time + readout
time.
.. index:: gain_setting (field)
**gain_setting**: (optional) :ref:`NX_CHAR <NX_CHAR>`
The gain setting of the detector. This influences background.
.. index:: saturation_value (field)
**saturation_value**: (optional) :ref:`NX_INT <NX_INT>`
The value at which the detector goes into saturation.
Data above this value is known to be invalid.
.. index:: sensor_material (field)
**sensor_material**: (required) :ref:`NX_CHAR <NX_CHAR>`
At times, radiation is not directly sensed by the detector.
Rather, the detector might sense the output from some
converter like a scintillator.
This is the name of this converter material.
.. index:: sensor_thickness (field)
**sensor_thickness**: (required) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
At times, radiation is not directly sensed by the detector.
Rather, the detector might sense the output from some
converter like a scintillator. This is the thickness of this
converter material.
.. index:: threshold_energy (field)
**threshold_energy**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_ENERGY <NX_ENERGY>`}
Single photon counter detectors can be adjusted for a certain
energy range in which they work optimally. This is the energy
setting for this.
.. index:: type (field)
**type**: (optional) :ref:`NX_CHAR <NX_CHAR>`
Description of type such as scintillator,
ccd, pixel, image
plate, CMOS, ...
**(transformations)**: (required) :ref:`NXtransformations`
Location for axes (transformations) to do with the
detector
**(collection)**: (optional) :ref:`NXcollection`
Suggested container for detailed non-standard detector
information like corrections applied automatically or
performance settings.
**(detector_module)**: (required) :ref:`NXdetector_module`
Many detectors consist of multiple smaller modules that are
operated in sync and store their data in a common dataset.
To allow consistent parsing of the experimental geometry,
this application definiton requires all detectors to
define a detector module, even if there is only one.
This group specifies the hyperslab of data in the data
array associated with the detector that contains the
data for this module. If the module is associated with
a full data array, rather than with a hyperslab within
a larger array, then a single module should be defined,
spanning the entire array.
.. index:: data_origin (field)
**data_origin**: (required) :ref:`NX_INT <NX_INT>`
A dimension-2 or dimension-3 field which gives the indices
of the origin of the hyperslab of data for this module in the
main area detector image in the parent NXdetector module.
The data_origin is 0-based.
The frame number dimension (np) is omitted. Thus the
data_origin field for a dimension-2 dataset with indices (np, i, j)
will be an array with indices (i, j), and for a dimension-3
dataset with indices (np, i, j, k) will be an array with indices
(i, j, k).
The order of indices (i, j or i, j, k) is slow to fast.
.. index:: data_size (field)
**data_size**: (required) :ref:`NX_INT <NX_INT>`
Two or three values for the size of the module in pixels in
each direction. Dimensionality and order of indices is the
same as for data_origin.
.. index:: data_stride (field)
**data_stride**: (optional) :ref:`NX_INT <NX_INT>`
Two or three values for the stride of the module in pixels in
each direction. By default the stride is [1,1] or [1,1,1],
and this is the most likely case. This optional field is
included for completeness.
.. index:: module_offset (field)
**module_offset**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
Offset of the module in regards to the origin of the detector in an
arbitrary direction.
.. index:: transformation_type (field attribute)
**@transformation_type**: (required) :ref:`NX_CHAR <NX_CHAR>`
Obligatory value: ``translation``
.. index:: vector (field attribute)
**@vector**: (required) :ref:`NX_CHAR <NX_CHAR>`
.. index:: offset (field attribute)
**@offset**: (required) :ref:`NX_CHAR <NX_CHAR>`
.. index:: depends_on (field attribute)
**@depends_on**: (required) :ref:`NX_CHAR <NX_CHAR>`
.. index:: fast_pixel_direction (field)
**fast_pixel_direction**: (required) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
Values along the direction of fastest varying pixel direction.
The direction itself is given through the vector attribute
.. index:: transformation_type (field attribute)
**@transformation_type**: (required) :ref:`NX_CHAR <NX_CHAR>`
Obligatory value: ``translation``
.. index:: vector (field attribute)
**@vector**: (required) :ref:`NX_CHAR <NX_CHAR>`
.. index:: offset (field attribute)
**@offset**: (required) :ref:`NX_CHAR <NX_CHAR>`
.. index:: depends_on (field attribute)
**@depends_on**: (required) :ref:`NX_CHAR <NX_CHAR>`
.. index:: slow_pixel_direction (field)
**slow_pixel_direction**: (required) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
Values along the direction of slow varying pixel direction. The
direction itself is given through the vector attribute
.. index:: transformation_type (field attribute)
**@transformation_type**: (required) :ref:`NX_CHAR <NX_CHAR>`
Obligatory value: ``translation``
.. index:: vector (field attribute)
**@vector**: (required) :ref:`NX_CHAR <NX_CHAR>`
.. index:: offset (field attribute)
**@offset**: (required) :ref:`NX_CHAR <NX_CHAR>`
.. index:: depends_on (field attribute)
**@depends_on**: (required) :ref:`NX_CHAR <NX_CHAR>`
**(beam)**: (required) :ref:`NXbeam`
.. index:: incident_wavelength (field)
**incident_wavelength**: (required) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_WAVELENGTH <NX_WAVELENGTH>`}
In the case of a monchromatic beam this is the scalar
wavelength.
In the case of a polychromatic beam this is an array of
the wavelengths with the relative weights in
incident_wavelength_weight.
.. index:: incident_wavelength_weight (field)
**incident_wavelength_weight**: (optional) :ref:`NX_FLOAT <NX_FLOAT>`
In the case of a polychromatic beam this is an array of the
relative weights of the corresponding wavelengths in
incident_wavelength.
.. index:: incident_wavelength_spread (field)
**incident_wavelength_spread**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_WAVELENGTH <NX_WAVELENGTH>`}
The wavelength spread FWHM for the corresponding
wavelength(s) in incident_wavelength.
.. index:: flux (field)
**flux**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_FLUX <NX_FLUX>`}
flux incident on beam plane area in photons per second per unit area
.. index:: total_flux (field)
**total_flux**: (required) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_FREQUENCY <NX_FREQUENCY>`}
flux incident on beam plane in photons per second
.. index:: incident_beam_size (field)
**incident_beam_size[2]**: (recommended) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
Two-element array of FWHM (if Gaussian or Airy function) or
diameters (if top hat) or widths (if rectangular) of beam
in the order x, y
.. index:: profile (field)
**profile**: (recommended) :ref:`NX_CHAR <NX_CHAR>`
The beam profile, Gaussian, Airy function, top-hat or
rectangular. The profile is given in the plane of
incidence of the beam on the sample.
Any of these values: ``Gaussian`` | ``Airy`` | ``top-hat`` | ``rectangular``
.. index:: incident_polarisation_stokes (field)
**incident_polarisation_stokes[np, 4]**: (recommended) :ref:`NX_CHAR <NX_CHAR>`
**incident_wavelength_spectrum**: (optional) :ref:`NXdata`
**(source)**: (required) :ref:`NXsource`
The neutron or x-ray storage ring/facility.
.. index:: distance (field)
**distance**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
Effective distance from sample
Distance as seen by radiation from sample. This number should be negative
to signify that it is upstream of the sample.
.. index:: name (field)
**name**: (required) :ref:`NX_CHAR <NX_CHAR>`
Name of source
.. index:: short_name (field attribute)
**@short_name**: (optional) :ref:`NX_CHAR <NX_CHAR>`
short name for source, perhaps the acronym
.. index:: type (field)
**type**: (optional) :ref:`NX_CHAR <NX_CHAR>`
type of radiation source (pick one from the enumerated list and spell exactly)
Any of these values:
* ``Spallation Neutron Source``
* ``Pulsed Reactor Neutron Source``
* ``Reactor Neutron Source``
* ``Synchrotron X-ray Source``
* ``Pulsed Muon Source``
* ``Rotating Anode X-ray``
* ``Fixed Tube X-ray``
* ``UV Laser``
* ``Free-Electron Laser``
* ``Optical Laser``
* ``Ion Source``
* ``UV Plasma Source``
.. index:: probe (field)
**probe**: (optional) :ref:`NX_CHAR <NX_CHAR>`
type of radiation probe (pick one from the enumerated list and spell exactly)
Any of these values:
* ``neutron``
* ``x-ray``
* ``muon``
* ``electron``
* ``ultraviolet``
* ``visible light``
* ``positron``
* ``proton``
.. index:: power (field)
**power**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_POWER <NX_POWER>`}
Source power
.. index:: emittance_x (field)
**emittance_x**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_EMITTANCE <NX_EMITTANCE>`}
Source emittance (nm-rad) in X (horizontal) direction.
.. index:: emittance_y (field)
**emittance_y**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_EMITTANCE <NX_EMITTANCE>`}
Source emittance (nm-rad) in Y (horizontal) direction.
.. index:: sigma_x (field)
**sigma_x**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
particle beam size in x
.. index:: sigma_y (field)
**sigma_y**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_LENGTH <NX_LENGTH>`}
particle beam size in y
.. index:: flux (field)
**flux**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_FLUX <NX_FLUX>`}
Source intensity/area (example: s-1 cm-2)
.. index:: energy (field)
**energy**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_ENERGY <NX_ENERGY>`}
Source energy.
For storage rings, this would be the particle beam energy.
For X-ray tubes, this would be the excitation voltage.
.. index:: current (field)
**current**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_CURRENT <NX_CURRENT>`}
Accelerator, X-ray tube, or storage ring current
.. index:: voltage (field)
**voltage**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_VOLTAGE <NX_VOLTAGE>`}
Accelerator voltage
.. index:: frequency (field)
**frequency**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_FREQUENCY <NX_FREQUENCY>`}
Frequency of pulsed source
.. index:: period (field)
**period**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_PERIOD <NX_PERIOD>`}
Period of pulsed source
.. index:: target_material (field)
**target_material**: (optional) :ref:`NX_CHAR <NX_CHAR>`
Pulsed source target material
Any of these values:
* ``Ta``
* ``W``
* ``depleted_U``
* ``enriched_U``
* ``Hg``
* ``Pb``
* ``C``
.. index:: number_of_bunches (field)
**number_of_bunches**: (optional) :ref:`NX_INT <NX_INT>`
For storage rings, the number of bunches in use.
.. index:: bunch_length (field)
**bunch_length**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_TIME <NX_TIME>`}
For storage rings, temporal length of the bunch
.. index:: bunch_distance (field)
**bunch_distance**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_TIME <NX_TIME>`}
For storage rings, time between bunches
.. index:: pulse_width (field)
**pulse_width**: (optional) :ref:`NX_FLOAT <NX_FLOAT>` {units=\ :ref:`NX_TIME <NX_TIME>`}
temporal width of source pulse
.. index:: mode (field)
**mode**: (optional) :ref:`NX_CHAR <NX_CHAR>`
source operating mode
Any of these values:
* ``Single Bunch``: for storage rings
* ``Multi Bunch``: for storage rings
.. index:: top_up (field)
**top_up**: (optional) :ref:`NX_BOOLEAN <NX_BOOLEAN>`
Is the synchrotron operating in top_up mode?
.. index:: last_fill (field)
**last_fill**: (optional) :ref:`NX_NUMBER <NX_NUMBER>` {units=\ :ref:`NX_CURRENT <NX_CURRENT>`}
For storage rings, the current at the end of the most recent injection.
.. index:: time (field attribute)
**@time**: (required) :ref:`NX_DATE_TIME <NX_DATE_TIME>`
date and time of the most recent injection.
**notes**: (optional) :ref:`NXnote`
any source/facility related messages/events that
occurred during the experiment
**bunch_pattern**: (optional) :ref:`NXdata`
For storage rings, description of the bunch pattern.
This is useful to describe irregular bunch patterns.
.. index:: title (field)
**title**: (required) :ref:`NX_CHAR <NX_CHAR>`
name of the bunch pattern
**pulse_shape**: (optional) :ref:`NXdata`
source pulse shape
**geometry**: (optional) :ref:`NXgeometry`
"Engineering" location of source
**distribution**: (optional) :ref:`NXdata`
The wavelength or energy distribution of the source
**NXDL Source**:
https://github.com/nexusformat/definitions/blob/master/applications/NXmx.nxdl.xml