[Olympus] Updated TDR for Friday

Frank Maas maas at kph.uni-mainz.de
Thu Dec 10 06:50:47 EST 2009 

Dear Stan, 

it depends on what you call critical, 
with the dimensions of the crystals, 
we will just sit very close to the beam line, 
depending on the beam tube diameter
there might be evennot 5mm space.
best regards
Frank(M)



Am 10.12.2009 um 12:30 schrieb Belostotski, Stanislav:

> Dear Frank M  and collegues,
> 
> Perhaps , I misunderstood anything(?) As I wrote in the  previous mail(s), for Bhabha /Moeller symmetric monitor, change from 2.0 to 2.3 gev means practically just minor changes: the symmetric angle changes to 1.19 (compared to 1.28 at 2 geV). If the monitor position is at 3 m from the IP the corresponding shift towards  the beam line is less than a half of cm (each side).Is that so critical?
> 
> As I understand at the meeting we agreed that only central counter of 9 (each side) will detect the coincidences.I believe this is the only reasonable solution in our case  In this case
>               > @Lumi=2.81 1/cm2sec ( @2GeV)
>>>> Bhabha coincedence rate(e+e- or e-e+ and  gamma*gamma)= 27.1 kHz Moller coincedence rate(e-e-) = 55.6 kHz
> quite enough for a good statistics.
> The kinematic dependence of  E(theta) within one counter  is not so sharp.
> The edge track  inefficiencies of the calorimeter  is totally excluded.
> 
> The plots showing distributions of the coincidences in the central counters (as well as inclusive count rate distributions) sent by me to Richard (and all) may of course be easily recalculated for 2.3 Gev, but i am sure there will be no noticeable change except this (mentioned above) shift of the two blocks towards the beam by 0.44cm.
> 
> With best Regards, StanB
> 
> Frank Maas wrote:
>> Dear All, I agree with FrankB. For the symmetric Moeller lumi monitor
>> we are at 2.0 GeV already at the edge of the beam line.
>> If the symmetric Moeller pair is not at the center, the system should still work, but in order to tell this we have to do ore simulations and
>> that takes time.
>> best regards
>> Frank
>> Am 09.12.2009 um 16:33 schrieb Brinker, Frank:
>>> Hi,
>>> Of course the clean way is to include numbers for both energies. If this
>>> is not possible in the short time I think it's also fine to leave it as
>>> it is now. - The planned energy for the experiment is 2.0 GeV. - What's already proved is an energy of 2.3 GeV. One could add a sentence like : Since no parameter depends criticaly on
>>> the energy 2.3 GeV could also be accepted.
>>> 
>>> Best regards
>>> Frank Brinker
>>> 
>>>> -----Original Message-----
>>>> From: Calarco [mailto:jrc at einstein.unh.edu] Sent: Wednesday, 09 December, 2009 14:40
>>>> To: FWD_kisselev
>>>> Cc: Brinker, Frank; olympus at mit.edu
>>>> Subject: Re: [Olympus] Updated TDR for Friday
>>>> 
>>>> 
>>>> The obvious solution is to include numbers for both 2.0 and 2.3 GeV  plus a statement that the ring has been run at 2.3 GeV and while we  plan to try to run at 2.0, we will accept 2.3 if that is not possible.
>>>> 
>>>> Sent from my iPhone
>>>> 
>>>> On Dec 9, 2009, at 2:12 AM, Alexander Kisselev <kisselev at mail.desy.de>  wrote:
>>>> 
>>>>> Dear Frank,
>>>>> 
>>>>>> I think, I should remind you, that we have'nt stored beam 
>>>> in DORIS at 
>>>>>> 2.0 GeV but only at 2.3 GeV. I'm not quite sure that we will be
>>>>>> able to
>>>>>> reduce the energy further while maintaining beam current and  stability.
>>>>> so what would be the proper way to quote the proposed beam 
>>>> energy in 
>>>>> the TDR? There are now several places in the text where 2.0GeV is mentioned explicitely. In particular on p.16 "we propose to run only
>>>>> at
>>>>> one beam energy, 2.0GeV". In several cases (table 1.2, figure 1.8,
>>>>> synchrotron radiation section, beam life time calculation, 
>>>> kinematic  
>>>>> range
>>>>> plots, ep-elastic luminosity monitor counting rates) 2.0GeV 
>>>> was used  
>>>>> to
>>>>> do numerical estimates.
>>>>> 
>>>>> Regards,
>>>>>  Alexander.
>>>>> 
>>>>>> Please be aware of this before fixing any hardware 
>>>> sensitive to a 15% 
>>>>>> energy change. I guess this might be the case for the 
>>>> Moeller/Bahbha 
>>>>>> Lumi Monitor, right?
>>>>>> 
>>>>>> With my best regards,
>>>>>> Frank Brinker
>>>>>> 
>>>>>>> -----Original Message-----
>>>>>>> From: olympus-bounces at mit.edu [mailto:olympus-bounces at mit.edu] On Behalf Of Belostotski, Stanislav
>>>>>>> Sent: Tuesday, December 08, 2009 5:42 PM
>>>>>>> To: Richard G Milner
>>>>>>> Cc: olympus at mit.edu
>>>>>>> Subject: Re: [Olympus] Updated TDR for Friday
>>>>>>> 
>>>>>>> 
>>>>>>> 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 =
>>>>>>> 1.28deg.=22.3mrad
>>>>>>> 
>>>>>>> distance between the IP and  front plane of symmetrically 
>>>> positioned 
>>>>>>> 3x3 counters(shown in figure attached)=300 cm along the beam;
>>>>>>> 
>>>>>>> Only central counters of  3x3 counter calorimeter blocks detect MOLLER/BHABHA coincedences
>>>>>>> 
>>>>>>> @Lumi=2.81 1/cm2sec
>>>>>>> Bhabha coincedence rate(e+e- or e-e+ and  gamma*gamma)= 27.1 kHz Moller coincedence rate(e-e-) = 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."
>>>>>>> ---------------------------------------------------------------
>>>>>>> ---------------------------
>>>>>>> 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 
>>>>>>>> official 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 the 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 include them. best regards, Richard _______________________________________________
>>>>>>>> Olympus mailing list
>>>>>>>> Olympus at mit.edu
>>>>>>>> http://mailman.mit.edu/mailman/listinfo/olympus
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