Minutes of the alignment meeting at DESY 09/11/01   (T.Zeuner)

(present Hartwig Albrecht, Martin Braeuer, Dirk Kruecker, Dmitri Golubkov,
Torsten Zeuner)


Reprocessing status :

Dirk told that last night hbserv did not work therefore some of his
alignment jobs died, he will not be ready with the new constants by monday
but mid of next week.

Torsten showed problems he observed with the Cats momentum determination
in PC. These problems are currently investigated by Yuri G. and Dimitri E.

Therefore we recommend that the reprocessing tests start only mid of next
week. The keytable should be prepared on wednesday.

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Concerning our next steps to better understand the alignment we agreed
that we will need some MC sudies. For these studies it is needed to apply
alignment files also for MC. To not double the work we decided that Dirk
will have a look into the OTR how to apply an alignment file to MC, for
the VDS Martin will do this job. For the ITR it is possible in the
digitisation to apply alignment files. An offical way how to apply
alignment files to MC will be worked out till the next large meeting (date
see below).

For the alignment studies on real data we agreed to concentrate on run
17137. To avoid problems with different track selections we decided to
create a special alignment DST file for this run. The reconstruction will
be based on the kumac for repro2, only RTRAs with a momentum larger than 6
GeV and containing a VDS segment (> 6 hits) and maintracker segment
(> 15hits) and an ECAL cluster will be stored. The DST will contain the
RTRA, RSEG, HITB and RCCL information and the relation between RTRA and
RSEG. This file allows for fast independent tests of the alignment by
different methods without redoing the reconstruction and by using a common
track selection.
Dmitri will produce this DST file.

We discussed what can be learned from last year operation, especially
concerning the different alignment periods produced by frequent accesses
to the detector. It was a hard job afterwards to find out when and which
detector was accessed. Therefore we have the strong request that with the
startup of operation all detector accesses are written to a logbook. Given
which chambers have been accessed and the data file before and after the
access. We will discuss with Achim how these problems of last year can be
handled in an appropiate way.


The last item was the meeting propossed by Federico (20. of
Nov.).  This date is most probably in conflict with the Access days.
Therefore we agreed that the meeting should take place one week
later, 27.11.01.