Dectris EIGER 2 - Additional Configuration Parameters

The lewriter name_pattern sets the name for the HDF5 les. When using the pattern ”$id”, it will be replaced
with a sequence identication number and can be used to dierentiate between subsequent series. The se-
quence identication number is reset after initializing the detector. The parameter nimages_per_le sets the
number of images stored per data le. A value of 1000 (default) means that for every 1000th image, a data le
is created. If for example, 1800 images are expected to be recorded, the arm, trigger, disarm sequence means
that a master le is created in the data directory after arming the detector. The trigger starts the image series
and after 1000 recorded images one data container is made available on the buer of the detector control unit.
No further les will made available until the series is nished either by completing the nth image (nimages) of
the nth trigger (ntrigger) or by ending the series using the detector command disarm. As soon as either criteria
is met the second data container is closed and made available for fetching.
7.3.2. Additional Conguration Parameters
Information #4
The following parameters are for special conditions and should be set with care and with un-
derstanding of the consequences. Changing these parameters to non-default values can have
a substantial negative impact on data quality!
• detector | cong | threshold/n/energy
• detector | cong | threshold/n/mode
• detector | cong | threshold/dierence/mode
The EIGER2 detectors provide two independent thresholds and it is possible to read out either one threshold,
all of them at once or the dierence of the thresholds. Reading out more than one threshold at a time is pos-
sible with the stream2, lewriter2 or monitor interfaces. The thresholds can be enabled or disabled using the
threshold/n/mode conguration parameter, where n is the threshold number. The dierence mode is enabled
with the threshold/dierence/mode parameter. Enabling the dierence mode will automatically disable the
threshold/n/mode parameters.
The threshold energy of the lower threshold (n=1) is set automatically to 50 % of the photon_energy. Thresh-
old/1/energy should only be changed in cases where the suppression of uorescence is a necessity in the
experiment. The threshold/1/energy must be kept within 50 % to 80 % of the incoming photon_energy. The API
incorporates no sanity check on the threshold/n/energy.
Corrections are enabled by default, but can be turned o using the following detector conguration parame-
ters. In the vast majority of experiments data quality benets from the data corrections. Therefore, disabling
either correction will likely result in inferior data quality.
• detector | cong | countrate_correction_applied
• detector | cong | ateld_correction_applied
• detector | cong | pixel_mask_applied
Further parameters, represented by the following selection, allow to enrich the meta-data of the image (series)
with experimental data.
• beam_center_x
• beam_center_y
• detector_distance
• detector_orientation
• detector_translation
• wavelength (see section 7.4.1 for dependency with photon_energy)
Further parameters and their function are described in the API Reference.
DECTRIS EIGER
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2 User Manual v1.8.2 15 | 36