[Olympus] remaining program

[Douglas Kenneth Hasell]

Hi,

	I would vote to NOT have another energy calibration run.  It is unfortunate that the last measurement was unsuccessful but looking at the existing monitoring of the energy with Uwe I am reasonably confident that the variations are on the order of 10^-4 or at least can be corrected for to this level.

Cheers,
Douglas

On Dec 20, 2012, at 4:43 PM, Brinker, Frank wrote:

> Dear all,
> Beside the program you discuss here I want to ask whether another energy
> calibration is wanted.
> We have a calibration for e+ and e- from mid of November  and for e+
> from Dec 22nd.
> A try for e- in December was not successful.
> 
> I can offer to try another calibration in the night from Dec 31st to Jan
> 1st.
> 
> Best regards
> Frank Brinker
> 
>> -----Original Message-----
>> From: olympus-bounces at mit.edu [mailto:olympus-bounces at mit.edu] On
>> Behalf Of Michael Kohl
>> Sent: Thursday, December 20, 2012 2:14 PM
>> To: olympus at mit.edu
>> Subject: [Olympus] remaining program
>> 
>> Dear all,
>> 
>> we have collected 3.2 fb^-1 so far, almost close to the design
>> luminosity.
>> 
>> For the 12-day addendum we should make a plan for a set of additional
>> measurements that could be helpful for the analysis.
>> 
>> Here is my proposal for low-luminosity running:
>> -run all four configs (e+-,B+-) without shielding but with the
> intensity
>> reduced to optimze the noise, each for a day.
>> E.g. reduce lumi by x10, expect ~3Hz elastics = 250k elastic events per
>> day -> 20 mA current / 0.2 sccm flow;
>> vary the magnetic field (100%, 75%, 50%, 25%) every six hours.
>> Open up the trigger by reducing the prescale on the 3-of-4 trigger type
>> to max out the DAQ (<30-40% deadtime).
>> 
>> This would cost us four days of running.
>> A data set with minimized noise can help us train and optimize the
>> reconstruction software, rather than using "noisy" high-luminosity
> data.
>> 
>> A dataset with minimized moise in all four configs will show how the
>> cancelations in the ratio occur and will help us validate the MC.
> Varying
>> the magnetic field in addition will serve the same purpose. The
> statistics
>> will be good enough for the validation at forward angles, where also
> the
>> systematic effects on the single-polarity ratio were the largest.
>> In the end we will need to be able to trust the MC for B+ at low
> epsilon.
>> 
>> At low luminosity, a trigger which is more more open also allows to
> verify
>> TOF and trigger efficiencies, and to break any inefficiencies further
> down
>> as a function of channels, coordinates etc.
>> 
>> We should start producing that set of measurements beginning on
> Saturday,
>> so that it could be finished by Wednesday. If it takes longer we still
>> have a few days left. Any final remaining days would be used to further
>> improve the statistics.
>> Frank Brinker also would like to do another Touchek energy measurement,
>> probably on Dec 31 / Jan 1.
>> 
>> If you have further ideas or wishes, please bring them up.
>> 
>> Best regards
>>  Michael
>> 
>> 
>> 
>> +---------------------------------------------------------------------
>> | Dr. Michael Kohl, Assistant Professor and Staff Research Scientist
>> | Physics Department, Hampton University, Hampton, VA 23668
>> | Jefferson Lab, C117, 12000 Jefferson Avenue, Newport News, VA 23606
>> | Phone: +1-757-727-5153 (HU), +1-757-269-7343 (Jlab)
>> | Fax:   +1-757-728-6910 (HU), +1-757-269-7363 (Jlab)
>> | Email: kohlm at jlab.org
>> | Cell:  +1-757-256-5122 (USA)
>> |
>> | Deutsches Elektronen-Synchrotron DESY, Bd. 66, Rm. 6,
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                                                    Cheers,
                                                            Douglas

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