[NeXus-tech] Revised PX application definition

[Mark Koennecke]

Hi,

find below my version of the PX application definition revised according to
our last Telco.

I took a possibly dubious decision here as I attached the polarisation 
parameters to
the source. My interpretation of wikipedia is that this is where the 
polarisation comes
from. Please correct me if this wrong.

diffrn_id:NXentry
    definition:NX_CHAR
    diffrn_id:NX_CHAR
    diffrn_scan_id:NX_CHAR
    measurement_details:NX_CHAR
    diffrn_crystal_id:NXsample
       diffrn_crystal_id:NX_CHAR
    instrument:NXinstrument
       source:NXsource
          name:NX_CHAR
          type:NX_CHAR
          current:NX_NUMBER
          probe:NX_CHAR
          polarisation_source_ratio:NX_NUMBER
          polarisation_source_norm:NX_NUMBER
       monochromator:NXmonochromator
          type:NX_CHAR
          radiation_id:NX_CHAR
          wavelength[] NX_NUMBER
          wavelength_weight[]:NX_NUMBER
       collimator:NXcollimator
          beam_divergence[]:NX_NUMBER
          collimation:NX_CHAR
       detector:NXdetector
          type:NX_CHAR
          frame_start_number:NX_NUMBER
          frame_end_number:NX_NUMBER
          description:NX_CHAR
          data[NP,XDIM,YDIM]
          x[XDIM]:NX_AXIS
          y[YDIM]:NX_AXIS
          azimuthal_angle:NX_AXIS
          distance:NX_AXIS
          height:NX_AXIS
          meridional_angle:NX_AXIS
          rotation_angle:NX_AXIS
          x_translation:NX_AXIS
          depends_on:NX_CHAR
          count_time[NP]:N_NUMBER
       goniometer:NXgoniometer
          chi[NP]:NX_AXIS
          phi[NP]:NX_AXIS
          rotation_angle[NP]:NX_AXIS
          depends_on:NX_CHAR
   data:NXdata
          link to instrument/detector/data
          link to instrument/goniomter/rotation_angle
          etc.


I took some liberties:
- I added some fields to NeXus base classes
- I use NX_AXIS which have not yet aggreed upon. Which means that the 
thing is
   a NeXus axis with the attributes: transfromation_type, vector, 
offset,depends_on etc.
- I put the polarisation into NXsource. Because wikipedia told me that 
without further
   action the polrisation is a property of the source. Please tell me if 
I am wrong.

It is to be understood that the axes in NXgoniometer and NXdetector may 
vary. But that the
transformation necessary can always be constructed by following the 
depends_on chain.

In NXdata should be links to all the fields varied during the scan. 
Indicated by the etc.

Regards,


            Mark