[Imgcif-l] additional dictionary items to map marccd exposure, integration, readout times?

[Michael Blum]

marccd (the program)  measures and records 3 elapsed times for each  
data frame.

They are:

exposure_time     - the time elapsed during which the shutter was open.
integration_time   - the time elapsed during which the detector  
accumulated signal
readout_time       - the time elapsed during which the detector was  
being read.

The original motivation to keep these times in the header was to  
facilitate correcting for dark current accumulation, which occurs on a  
CCD during the integration time and, with a different shape, during  
the readout.

In practice, our detectors have such low dark current that this  
correction hasn't been necessary, BUT the recorded times have turned out
to be very useful for diagnosis of beamline hardware, detector  
hardware, and beamline-detector synchronization problems.

Currently, when writing CBF files, I can only store one of these  
numbers.  I store
the "exposure" time in diffrn_scan_frame.integration_time

I would like to propose that the other times be added to the  
diffrn_scan_frame category, but I don't know what to propose for
the names, since there is already a conflict between the current  
dictionary and my naming convention.

Possibly:
integration_time
detector_integration_time
detector_readout_time

or
integration_time
accumulation_time
readout_time


regards,

Michael

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Michael L. Blum                    Toll Free: 877-627-XRAY (627-9729)
Rayonix, LLC                        Tel: 847-869-1548
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