[Olympus] Fwd: questions prior to review

[Richard G Milner]

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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