[Nexus] NXdata for an "10-channel" high resolution detector

[Carlos Pascual]

Hi Eugen,

are you using Sardana  foracquiring and  writing the data?

If so, it should be possible to create a custom recorder that writes the 
concatenated data on-the-fly.

Carlos

On Mon 10 June 2013 23:59:14 Wintersberger, Eugen wrote:
> Thanks guys for the suggestions
> 
> Currently we are storing the data like at SOLEIL. However, I would agree
> with mark that a single array would be much more comfortable for
> plotting. The problem with this is that we are writing data in a
> record-style manner. This means at every point a new data item is
> appended to the data field of the individual detectors. By doing so we
> can ensure that every point data is written to disk - even if the scan
> breaks accidentally. The only chance we would have is to do the
> concatenation afterwards once the scan is finished.
> 
> Seems that I have to think about which direction we would go ;)
> 
> regards
>   Eugen
> 
> PS: we had now the first beamtime with the new Lambda detector developed
> at DESY which will natively write Nexus files. The uses had no problem
> with this so far ;)
> 
> On Mon, 2013-06-10 at 16:52 +0200, Mark Koennecke wrote:
> > Eugen,
> > 
> > On 06/10/2013 04:20 PM, Wintersberger, Eugen wrote:
> > > Hi folks
> > > 
> > >    I have a question concerning NXdata. We are currently starting with
> > > 
> > > Nexus at our beamlines here at DESY. P02 - a powder diffraction
> > > beamline - will be the first one to use Nexus.
> > > They have a kind of 10-channel detector which is in reality a curved
> > > detector consisting of 10 individual point detectors each having an
> > > analyzer in front of them. The angular offset between the detectors is
> > > about 1 degree. We store each individual detector in a separate
> > > NXdetector group. The full scan data can be obtained by concatenating
> > > the data and polar_angle fields of each of the 10 detectors.
> > > The question is now: what should go to the NXdata group? Can I have 10
> > > individual pairs of of data/(variable or x??) in a single NXdata group
> > > or do I have to create 10 individual NXdata groups?
> > > regards
> > > 
> > >    Eugen
> > 
> > The plot you want from a  powder diffractometer is polar_angle versus
> > counts.
> > Thus I would concatenate in the DAQ software and store that in NXdata.
> > If you
> > have concerns about the concatenation done in the DAQ you can still go
> > back to
> > the individual detectors. You may also wish to store the concatenated
> > data as a
> > virtual NXdetector to make the relationship crystal clear.
> > 
> > Regards,
> > 
> >             Mark
> > > 
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> > 
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-- 
+----------------------------------------------------+
 Carlos Pascual Izarra
 Scientific Software Coordinator
 Computing Division
 Cells / Alba Synchrotron  [http:/www.cells.es]
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