[Olympus] Fwd: questions prior to review
Michael Kohl
kohlm at jlab.org
Tue Sep 15 04:39:49 EDT 2009
Hi Richard and all,
I did a quick back-of-the envelope calculation for the sensitivity of the
lumi rate with the horizontal beam position: Assuming Mott cross section
for the angular dependence at low Q2, I get a change in the elastic rate
at 12 degrees of 1% for a beam shift of 1 mm. This will be studied with
MC in detail.
On the TOF time resolution: In P. Karpius' thesis the intrinsic resolution
is reported with 350 ps FWHM (i.e. 150 ps sigma).
The width of the timing peaks in the TDR from C. Crawford's plot (400ps)
refers to the width of the elastic e-p coinctime which is somewhat broader
due to varying pathlengths etc.
Best regards
Michael
On Tue, 15 Sep 2009, Richard G Milner wrote:
> 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
>
>
> ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
> ) `\ -
> / '. | +
> | `, Elke-Caroline Aschenauer =
> \,_ `-/ -
> ,&&&&&V Brookhaven National Lab +
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>
> ----- End forwarded message -----
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