Header Groups
The DAQ software for DECTRIS EIGER detectors writes information (header, data) into a number of groups, all of which comply with the NeXus standard. The compilation below represents the state of the EIGER API version 1.5.
You may also download a PDF file documenting the header data written by the API (up to version 1.3).
Data
HDF5 path: /entry/data/
NX_class = NXdata
| NeXus Name | NeXus Data Type | Description |
|---|---|---|
| data_000001 | NX_UINT32[n,i,j] | Link to data file |
| data_000002 | NX_UINT32[n,i,j] | Link to data file |
| ... | NX_UINT32[n,i,j] | Link to data files |
| data_nnnnnn | NX_UINT32[n,i,j] | Link to data file |
NXdetector
HDF5 path: /entry/instrument/detector/
NX_class = NXdetector
| NeXus Name | NeXus Data Type | Description | Unit |
|---|---|---|---|
| beam_center_x | NX_FLOAT32 | Beam center in x in pixels. This is necessary for efficiency correction. Default value: beam_center_x = 0.5 * x_pixels_in_detector |
|
|
beam_center_y |
NX_FLOAT32 | Beam center in y in pixels. This is necessary for efficiency correction. Default value: beam_center_y = 0.5 * y_pixels_in_detector | |
|
bit_depth_readout |
NX_UINT32 | Bit depth of the internal readout | |
|
bit_depth_image |
NX_UINT32 | Bit depth of generated images | |
|
count_time |
NX_FLOAT32 | Exposure time per image, time during which detector counts X-rays | s |
|
countrate_correction_applied |
NX_BOOLEAN | Application of rate correction | |
|
description |
NX_CHAR | Information on detector type, model | |
|
detector_distance |
NX_FLOAT32 | Distance to detector | m |
| detector_number | NX_CHAR |
Detector serial number | |
|
detector_readout_time |
NX_FLOAT32 | Readout time of the detector for non-continuous readout (PILATUS) or dead time of continuous readout (EIGER). This defines the minimum time after which the detector can count again and acquire the next frame. | s |
|
efficiency_correction_applied |
NX_BOOLEAN | Application of sensor efficiency correction | |
|
flatfield_correction_applied |
NX_BOOLEAN | Application of flatfield correction | |
|
frame_time |
NX_FLOAT32 | Time interval between start of image acquisitions. This defines the speed of data collection and is inversely proportional to frame rate, the frequency of image acquisition. This parameter is recorded as "exposure_period" for PILATUS. | s |
|
pixel_mask_applied |
NX_BOOLEAN | Application of pixel mask to data | |
|
sensor_material |
NX_CHAR | Sensor material, e.g. Si | |
|
sensor_thickness |
NX_FLOAT32 | Thickness of the sensor | m |
|
threshold_energy |
NX_FLOAT32 | Threshold energy of the detector | eV |
|
virtual_pixel_correction_applied |
NX_BOOLEAN | Application of virtual pixel correction | |
|
x_pixel_size |
NX_FLOAT32 | Pixel size in x | m |
|
y_pixel_size |
NX_FLOAT32 | Pixel size in y | m |
Detector Geometry
HDF5 path: /entry/instrument/detector/geometry/
NX_class = NXgeometry
A detailed description of the module and detector geometry can be found in the two files below.
| NeXus Name | NeXus Data Type | Description |
|---|---|---|
| orientation/value | NX_FLOAT32[6] | Two vectors describing tilt of detector relative to laboratory frame. |
| translation/distances | NX_FLOAT32[3] | Orthogonal distances of first pixel of the detector from the origin of the laboratory frame. |
Detector Specific Information
HDF5 path:/entry/instrument/detector/detectorSpecific/
NX_class = NXcollection
| NeXus Name | NeXus Data Type | Description | Unit |
|---|---|---|---|
| auto_summation | NX_BOOLEAN | Auto-summation was used, i.e. images are composed of summed frames | |
| calibration_type | NX_CHAR | (used internally) | |
| countrate_correction_bunch_mode | NX_UINT32 | Bunch mode of the count rate correction. Default value: continuous | |
|
countrate_correction_count_cutoff |
NX_CHAR |
Maximum count value for which an accurate count rate correction can be performed | |
|
data_collection_date |
NX_DATE_TIME | Date and time of data collection in ISO 8601 | |
|
detector_readout_period |
NX_FLOAT32 | (used internally) | s |
|
eiger_fw_version |
NX_FLOAT32 | Version of the EIGER firmware | |
|
element |
NX_CHAR | Element corresponding to photon energy (e.g. Cu => 8.04 keV) | |
|
flatfield |
NX_FLOAT32[i,j] | Flatfield correction data | |
|
frame_count_time |
NX_FLOAT32 | (used internally) | s |
|
frame_period |
NX_FLOAT32 | Effective time between the start of subsequent data collections. This is frame_time corrected for detector_readout_time. | s |
|
nframes_sum |
NX_UINT32 | Number of summed frames | |
|
nimages |
NX_UINT32 | Number of images | |
|
nsequences |
NX_UINT32 |
(used internally) | |
|
ntrigger |
NX_UINT32 | Number of triggers | |
|
number_of_excluded_pixels |
NX_UINT32 | Number of excluded (unreliable) pixels | |
|
photon_energy |
NX_FLOAT32 | Photon energy Default value: cp_photon_energy = 2* threshold_energy | eV |
|
pixel_mask |
NX_UINT32[i,j] | Contains a bit field for each pixel to signal dead, blind or high or otherwise unwanted or undesirable pixels. The bits have the following meaning: 0 gap (pixel with no sensor) 1 dead 2 under responding 3 over responding 4 noisy 5-31 -undefined- | |
|
software_version |
NX_CHAR | Software version used for data acquisition | |
|
summation_nimages |
NX_UINT32 | Number of subimages auto-summed to yield an image | |
|
trigger_mode |
NX_CHAR | Trigger mode, e.g. firmware_controlled (time-resolved), externally_triggered, externally_triggered_window, software control | |
|
x_pixels_in_detector |
NX_UINT32 | Number of pixels in detector in x direction | |
|
y_pixels_in_detector |
NX_UINT32 | Number of pixels in detector in y direction |
Goniometer
HDF5 path: /entry/sample/goniometer/
NX_class = NXtranslations
| NeXus Name | NeXus Data Type | Description | Unit |
|---|---|---|---|
| omega | NX_FLOAT32[n] | Starting omega value for each image | degrees |
| omega_end | NX_FLOAT32[n] | Omega end value for each image | degrees |
| omega_range_average | NX_FLOAT32 | Average omega value for dataset | degrees |
| omega_range_total | NX_FLOAT32 | Total omega range for dataset | degrees |
| phi | NX_FLOAT32[n] | Starting phi value for each image | degrees |
| phi_end | NX_FLOAT32[n] | Phi end value for each image | degrees |
| phi_range_average | NX_FLOAT32 | Average phi value for dataset | degrees |
| phi_range_total | NX_FLOAT32 | Total phi range for dataset | degrees |
| chi | NX_FLOAT32[n] | Starting chi value for each image | degrees |
| chi_end | NX_FLOAT32[n] | Chi end value for each image | degrees |
| chi_range_average | NX_FLOAT32 | Average chi value for dataset | degrees |
| chi_range_total | NX_FLOAT32 | Total chi range for dataset | degrees |
| kappa | NX_FLOAT32[n] | Starting kappa value for each image | degrees |
| kappa_end | NX_FLOAT32[n] | Kappa end value for each image | degrees |
| kappa_range_average | NX_FLOAT32 | Average kappa value for dataset | degrees |
| kappa_range_total | NX_FLOAT32 | Total kappa range for dataset | degrees |
Beam
HDF5 path: /entry/instrument/beam/
NX_class = NXbeam
| NeXus Name | NeXus Data Type | Description | Unit |
|---|---|---|---|
| incident_wavelength | NX_FLOAT32 | Wavelength of the beam in the case of monochromatic beam | angstrom |
