1/8/98

Final Report for the Drift Chamber Electronics Final Design Review
==================================================================

Held at SLAC, Thursday December 11, 1997

Committee:

Fred Kral, chair	(jfkral@lbl.gov)
Ray Rodriguez		(ray_rod@slac.stanford.edu) 
Perry Anthony		(anthony@slac.stanford.edu)
Nick Sinev		(sinev@slac.stanford.edu)

Ex-Officio:

Andy Lankford
Gunther Haller
Walt Innes


Summary
_______

The BaBar Drift Chamber electronics team is congratulated on a
well-executed design and pre-production test program.  We appreciated
the work that went into the documentation, presentations and educating
the committee.

The plans and schedule presented by the team for further
qualification before releasing the remaining items for production were
judged sensible by the committee.


Recommendations
_______________

* The bench test stand for the Front End Assembly (FEA) needs a more
complete standard test program.  For example, adding tests of every
memory location in the ELEFANT chips is recommended and should not add
much to the execution time.

* Automatic calibration of the many reference capacitors on the
stand-alone test stand calibration board is recommended, for ease of
future verification and re-calibration (e.g. several years from now).

* If not too much additional work, it is suggested that electronic ID
numbers be put on each FEA so that these can be read out through the
detector control system.  This would prevent accidental
mis-installation of FEAs over the lifetime of the experiment and the
ease manual book-keeping burden.

* Requirements on G-link maximum error rates need to be formulated for
both the DAQ and Trigger streams.  These are needed both for loss of
synchronization and data bit errors (which may be related).  A test
plan to verify that the electronics meets these requirements need to
be put into place.  Coordination with the trigger group is needed.

* Performance versus temperature for the Amplifier/Digitizer Board
(ADB) needs a detailed study.  It is not clear that the present
temperature sensor would be able to detect over-heating of the ADB
components such as the ELEFANT chip, given the present cooling method.
For the study, artificially increasing the temperature to calibrate
the temperature sensor is recommended, perhaps while instrumenting the
FEA with extra sensors on the bench.  In fact, there was concern over
the limited temperature monitoring: only one sensor per FEA.  We
recommend at least one sensor per ADB.  If this proves to be difficult
to implement at this stage, the study of performance versus
temperature becomes even more important.

* We discourage the team from linking its production schedule to the
availability of standard Readout Modules with working DataFlow
software.

* Add smoke detectors on the exhaust line from the electronics area.

* The team should make sure that some tests that would be overly
cumbersome or impossible in the final configuration at IR-2 need be
completed by the end of the Assembly Building testing period.  Such
tests include Glink loop-back tests.  It is seen as prudent to verify
that the same FEA located at different azimuthal locations performs
identically.

* The team is aware that it needs further electronics bench and system
tests before production is launched, includiung studies on crosstalk
and dE/dx.