[g2p_ana] Minutes of G2P|GEP weekly analysis meeting

[zhupengjia]

Hi Alexandre and Vince,
Thank you very much for your suggestions, unfortunately when I use the 
pedestal value for itself the result doesn't get better(we can not do 
run-by-run subtraction because a lot of runs are stable and don't have 
beam trip, the most closed way is using the most closed run's pedestal 
value,the pedestal didn't change much in a short time), and the problem 
of the current dependent is still appear in 100nA (though it is better 
than 50nA).
The calibration constant difference between 75nA and 50nA is much larger 
than between 100nA and 70nA, for example for bpm A x(better one) which 
is(with ped subtract)  :
100nA: -0.901074987358478 0.028868851417355 2.387399951051098
75nA : -0.856755468059708 -0.005854287652885 1.681694325042157
50nA: -0.713440219213956 0.072444814661664 2.438741146875114
and for without ped subtract:
100nA: -1.155462351157096 0.041404464454182 2.826371996079349
75nA: -1.186206089036325 0.013744756763266 2.325247200492234
50nA: -1.235578231194879 0.131146132895789 3.331838988641703
Another problem is we don't know if pedestal depend on current, as I 
understand there should be some additional pedestal effect caused by 
real signal, but I can not find a way to approve it.
Maybe I will use without ped subtract first and do the non linear fit 
for calibration data, and try to add current dependent parameter to 
calibration.
Thanks!

On Thu, 18 Jul 2013 11:55:27 -0400 (EDT) Vincent Sulkosky 
<vasulk at jlab.org> wrote:
>
> Hi Jixie,
>
> From Pengjia's presentation yesterday, I came away with a different 
> understanding.  I agree that he subtracts only an average pedestal, 
> but I thought he did that for each run and did not use one set of 
> pedestals for all runs.  Since the pedestal changes, he most 
> certaintly needs to do a run-by-run subtraction.
>
> Thanks,
> Vince
>
> -- 
>
> Vincent A. Sulkosky, MIT Senior Postdoctoral Associate
>
> CEBAF Center F358
> Jefferson Lab                Phone: (757) 269-5487
> 12000 Jefferson Avenue      Pager: (757) 584-5487
> Suite #4, MS 12            email: vasulk at jlab.org
> Newport News, VA 23606        Fax:   (757) 269-5703
>
> On Wed, 17 Jul 2013, Jixie Zhang wrote:
>
>> Dear all,
>>  The minutes for the weekly analysis meeting is ready here:
>> https://hallaweb.jlab.org/wiki/index.php/G2p_Analysis_Minutes#7.2F17.2F2013 
>>
>>
>> -- 
>> With Best Regards,
>> Jixie Zhang
>> 757-269-7735
>> _______________________________________________
>>

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