Dear Ian and others
A comment to your comment
As for the vdrift...
I think that the relative drift velocity seems (and note, I said 'seems', I didn't say 'has been proven beyond the shadow of a doubt') to fairly stable. Now that we have the fibers, we can check this quite easily and will do so. Still, does anyone have a good feeling for how much the vdrift must change to impact any measured physics variables?
I think that by requiring FFS tracks with a valid tof, one effectively makes a fiducial cut in the D2 magnet, which is what the y position would be used for.
-- Yes and no - In order to make proper fiducial cuts you do need to define a proper effective solid angle by a detector that
do measure this - and for FFS this is the T2 Y-direction. The D2 gap is not a defining aperture in the spectrometer as designed.
So in the end I would think the cross section will depend of y-drift,
It is also important for the matching and with a 'wrong' y-drift one may well change other parameters (e,g. vert. angles)
thus making this somewhat inconsistent. The effects are probably small if the Vdrift is reasonable close to the 'actual' values-
In any case we have to move forward with the analysis, but should remember the geometries though pretty good can in fact
be and more consistent - thus both with reconstruction analysis and improvements of geom. calibrations and code.
A comment to the reconstruction jobs -
I will suggest that not only the root- event files are saved, but also the histograms files, since these contain several important plots that shows the quality of reconstrucion, and will tell if the data being collected have problems, and may have to be repeated.
Also summatrizing what runs have been done via the list servers on a daily basis will be usefull.
Flemming
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