[Halld-offline] hits missing after pass thru evio encoding/decoding

Sean Dobbs s-dobbs at northwestern.edu
Wed Aug 27 12:56:49 EDT 2014

Hi Richard,

To answer your last question first, I've been checking the consistency of
this process, so I can answer at least some of your questions.

- The loss in FDC hits (which presumably causes the tracking problems you
see) is due to a known problem in the translation table for the FDC wires.
 A fix is on the way.

- I haven't seen the problems in BCAL showers that you're reporting (and I
just checked Monday!).  If you can provide some sample files, I can take a
look at this for you.


On Wed, Aug 27, 2014 at 11:45 AM, Richard Jones <richard.t.jones at uconn.edu>

>  Hello all,
>  I am working on validating the sim-recon-rj-pm branch before we check it
> into the trunk, and one of the things I am doing is making sure that the
> tagger hits that are now being decoded from the evio fADC/TDC structs are
> properly showing up as dana objects in the analysis. To do this, I am
> running simulation output files through the hddm -> evio converter and then
> reading the events back into dana from evio input files. The problem is
> that I am seeing lots of missing hits that get dropped during this
> coding/decoding process, and I wonder if this is correct. BTW, I also see
> it for trunk code, although the output from hdgeant is different between
> the two branches so I cannot do event-by-event comparisons.  Here is what I
> see:
>    - BCAL - same number of hits (DBCALHit objects), but major decrease in
>    the number of clusters (DBCALShower, DBCALCluster) that are made out of
>    them. Is something being incorrectly transmitted through the filter?
>    - FCAL - things all look consistent here
>    - CDC - same number of hits before and after
>    - FDC - 10% loss of hits (DFDCHit objects) , but major decrease in
>    higher level objects like DFDCPseudo, DFDCIntersection which have 90% loss.
>    - StartCounter - same number of hits before and after
>    - FTOF - some hits are missing, but the higher-level objects
>    (DTOFPaddleHit, DTOFPoint) seem consistent, maybe just a threshold cut?
>    - Track objects - there may be a correlation between the pre-filter
>    and post-filter statistics on these objects, but it is not obvious. The
>    counts are rarely consistent between them for any of the track objects.
>    - Neutrals objects - ditto.
> Is there someone who is taking the lead in studying the behavior of this
> filter? Should I ignore these differences, and consider the to/from evio
> capability of our offline to be unready for actual use?
>  -Richard J.

Sean Dobbs
Department of Physics & Astronomy
Northwestern University
phone: 847-467-2826
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