Dear Ramiro,
thanks for you message. I did not respond to your
first shift report because I did not understand the problem
very well. Of course it is essential that all detectors perform
and we all suffer if we go into production before detectors
are commisioned. My experience with the ZDC has been that even
after commisioning new problems can develop when the beam energy
and/or the electronic enviroment change. Because of limits on
the amount of time I am at BNL this year's problems could not
have been solved without substantial help from BNLers for which
I am grateful. For the ZDC the problem was obvious in that the
one neutron peak in early 2001 was much worse than in 2000.
However for tracking detectors the criteria for sucessful
commisioning are more complex. Perhaps we need some more formal
process to establish weather a detector is performing
satisfactorly.
Yours Michael
Quoting Ramiro Debbe <debbe@sgs1.hirg.bnl.gov>:
>
>
> Dear Collaborators,
>
> It is necessary for me to elaborate about what I said in a recent
> shift report where I voiced my discomfort about the state of detectors
> in our experiment.
> There was almost no immediate reaction to it, but recently an attempt
> to
> trivialize my concerns call for a reply.
>
> Whenever a new detectors starts acquiring data it is of utmost
> importance to study its performance parameters, prototype studies are
> usually done in clean controlled environments that do not account for
> new developments that can be related to backgrounds, higher
> multiplicities or just different manufacturing situations. New
> detectors
> should be studied extensively in situ before data production starts.
>
> Proportional counters should be studied thoroughly to find a parameter
> region with the highest detection efficiency. Parameters for
> proportional counters include:
> amplification gain controlled most closely by anode high voltage,
> amount of quencher in the gas mixture,
> definition of drift voltages to guaranty that the cells do not have
> dead
> regions,
> discriminator threshold.
>
> I suggested that these studies be done way at the beginning of the run.
> The replies to my original shift report implied that there is no need
> to
> worry because those studies are being conducted as we speak. That
> reasoning is not correct. I would like the collaboration to adopt the
> same standards that were used before the TPC were fully operational,
> but
> all within a clear cut professional style. Lets not get into a shouting
> match or rounds of sneering remarks.
> Lets make sure all our detectors are working at the top of their
> capabilities.
>
> Ramiro
>
>
> --------End of Unsent Message
>
Michael Murray, Cyclotron TAMU, 979 845 1411 x 273, Fax 1899
This archive was generated by hypermail 2b30 : Tue Oct 09 2001 - 17:50:46 EDT