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

 

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