[Olympus] Fwd: questions prior to review

[John R Calarco]

Richard, et al,

   Regarding the question on the ToF timing resolution, the answer is that
it was good enough and not too expensive. There could have been improvements
in using a higher light output scintillating material (more expensive) and
more expensive PMTs. Many years ago I took one of the Hall A focal plane
scintillators to UNH and quickly proved to Bogdan W that I could improve
ToF resolution on it by more than a factor of 3 by putting a much better
PMT on each end. The cost was also a factor of 3. Finally, the light quides
were the simplest design to do ther job. And since the performance met spec
no further R&D was expended. There is a light collection simulation code
called Guide7 which I used in collaboratin on the Hall A RCS experiment
which allows one to vary light quide  design but we did not use it because
we did not need to.


> Dear OLYMPUS colleagues,
> I received this message from Elke this morning.  We should make an effort
> to
> address these issues in our talks.
> regards,
> Richard
>
>
> ----- Forwarded message from elke at kirk.desy.de -----
>     Date: Tue, 15 Sep 2009 05:09:34 +0200 (CEST)
>     From: Elke-Caroline Aschenauer <elke at kirk.desy.de>
> Reply-To: Elke-Caroline Aschenauer <elke at kirk.desy.de>
>  Subject: questions prior to review
>       To: "Lehner, Frank" <frank.lehner at desy.de>
>
>
> Dear all,
>
> in view of the restricted time tomorrow for the review here some
> questions, which occurred to me reading the TDR.
> The questions are organized according to the sections in the TDR.
>
> Chapter 1:
>
> How does Olympus compare with the other experiments proposed to study TPE
> -- advantages and disadvantages
>
> Can you elaborate a bit which stability of the detector was reached
> during the running of BLAST at MIT.
>
> Chapter 2:
>
> What is the material of the beam pipe.
> Is Beryllium considered because of synchrotron radiation.
> Are there drawings of the collimator system including the synchrotron
> radiation fans depending on their origin.  It was not clear the
> collimator system is one or two stage.
> Which type of beam slopes and drifts can be tolerated.
>
> Chapter 3:
> GEM-detectors:
> It is not completely clear the design for the GEM detector used in the
> lumi detector and for the tracking upgrade are the same or different, if
> they are different why?
> In view of the time scale and complexity of the detector would it not be
> good to agree on one design.
>
> Is there any interference (manpower, components) of the GEMs for the
> lumi-detector, which are close to the MIT STAR GEM tracker, with the
> production of the star gem tracker.
>
> ToF-system:
> why is the resolution so bad, for GlueX with similar bars the resolutions
> achieved are better than < 100ps
> http://www.jlab.org/Hall-D/reviews/Tracking_PID_REVIEW_Mar08/Final%20Talks/T7-tof-smith.pdf
> yes the bars are wider by a factor of 2 but a factor 3 less resolution.
> What is required on resolution for the experiment.
>
> Chapter 4:
> Are there any requirements on the beam position and slope stability
> page 60: I must admit that I don't understand the statement that bhabha
> and moeller scattering are the same. Bhabha scattering has a scattering
> and annihilation part in the cross section, moeller has only the
> scattering part, which makes the cross sections different by factors
> depending on the energy difference of the 2 leptons. So you must mean
> something else.
> The questions on the GEM are listed above.
>
> Overall:
> it would be nice to see a summary on the performance specifications driven
> by physics for each of the detector elements.
>
> Manpower:
> Table 8.1
> column one list faculty are these the people which are counted as FTEs in
> column 2 or are they in addition.
> Do the people in column 5 still need to be found and / or financed?
>
> Thanks elke
>
>
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-- 
John R Calarco
Dept of Physics
Univ of New Hampshire
phone: 603-862-2088
fax: 603-862-2998
email: calarco at unh.edu