[Olympus] Updated TDR for Friday

[Belostotski, Stanislav]

Dear Richard, Grate  that things are moving so fast.
We have prepared 3 pieces which may help drafting additions yet missing =

in TDR:
---------------------------------------------------------------------------=
-------------
MC STUDY OF MOLLER/BHABHA LUMI MONITOR
......................................
Configuration: symmetric ee scattering angle at 2 GeV =3D 1.28deg.=3D22.3mr=
ad

distance between the IP and  front plane of symmetrically positioned =

3x3 counters(shown in figure attached)=3D300 cm along the beam;

Only central counters of  3x3 counter calorimeter blocks detect =

MOLLER/BHABHA coincedences

@Lumi=3D2.81 1/cm2sec
Bhabha coincedence rate(e+e- or e-e+ and  gamma*gamma)=3D 27.1 kHz
Moller coincedence rate(e-e-) =3D 55.6 kHz

As an example,  distributions of inclusive Bhabha count rate    and =

coincidence rate (only charged e, without gamma*gamma)
  detected by the central counters ( @ 3 meters from IP) are shown in =

figure attached (eps and pdf): inclusive count (left panel, red points) =

and coincidence (right panel, blue points), respectively.



SLOW CONTROL
............
" Successful operation of the OLYMPUS experiment relies, in addition
to the detector electronics, trigger and DAQ, on numerous other
components which status has to be controlled, monitored and recorded.

   These include the high voltage for the PMTs and tracking chambers, low
voltage power supplies, the gas system for the tracking chambers and
GEMs, the electron (positron) beam current in the DORIS ring, beam
offsets and slopes at the OLYMPUS interaction area, gas target density,
toroid magnet current and others.

   These diverse components and bits of information will be organized
using Slow Control and Monitoring system similar to the one successfully
used over years in HERMES experiment at DESY. The system will be using
MySQL client-server interaction model and Tcl/Tk window interface for
visualization and online control. Collected information will be stored
in MySQL database as well as in the ROOT tree format, readily available
for the offline analysis."

BACKUP SOLUTION FOR GEM's 12deg. LUMI MONITOR
.............................................
  "The absolute measurement of luminosity ratios for electron and positron
running is very important  for OLYMPUS. Independently of the additional
Bhabha/Moeller monitor installation, Collaboration considers a =

possibility to strengthen
the already proposed GEM-based 12 degree ep-elastic scattering luminosity
monitor. An option to interleave GEM modules with the three XY 1mm pitch
proportional chambers, as well as to install scintillating counters with
~100ps timing resolution in both arms of the GEM luminosity monitor is
presently being evaluated."
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The last item is of course tentative being  in process of  discussion.
But it is important for PNPI group that it will be at least mentioned in =

TDR. As I understand for the Moscow  finance department (and also =

locally in PNPI) it is important that PNPI commitments/responsibility =

will be  clearly outlined and  documented.

Finally, we assume that PNPI  commitments/responsibilities  would be:
1.MC studies( MC simulations of Bhabha/Moeller luminosity monitor =

jointly with Frank Maas group, other MC tasks);
2.Slow Control ;
3.Backup solution for ep scattering luminosity monitor.

With my best regards StanB





Richard G Milner wrote:
> Dear OLYMPUS colleagues,
> I have learned to-day that the DESY Directorate would like to give offici=
al
> approval to OLYMPUS at its regular meeting next week. They have asked for=
 a
> revised TDR. I will provide this by the end of this week. I will update t=
he
> manpower and schedule information. I would also like to include a short
> description of the symmetric Moller detector, which can be expanded upon =
later.
> If you have edits that can be incorporated quickly I will do my best to i=
nclude
> them.
> best regards,
> Richard
> _______________________________________________
> Olympus mailing list
> Olympus at mit.edu
> http://mailman.mit.edu/mailman/listinfo/olympus
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