[Clas_cascades] Fwd: Re: analysisnote_Lambda1520_v3

[Zhiwen Zhao]

-------- Original Message --------
Subject: Re: [Clas_cascades] analysisnote_Lambda1520_v3
Date: Wed, 26 Jan 2011 15:16:39 -0500
From: Paul Mattione <pmatt at jlab.org>
To: Zhiwen Zhao <zwzhao at jlab.org>

No, I mean triggering efficiency.  The thresholds for SC detection are
20mV, but for triggering are 100mV.  Therefore you can have paddles
that reconstruct pi-'s just fine but that won't send trigger signals.
A really quick way to check is to look at the ADCs of reconstructed
pi-'s and see if they look as terrible as mine do (Trigger
efficiencies were set assuming the pedestal subtracted ADC is at 600):

http://clasweb.jlab.org/rungroups/g13/wiki_secure/index.php/PiMinusTriggerEfficiencyStudy#ADC_Study

eg3 may have been fine, I'm just wondering if you've looked into it.
The effect this has depends on your event topology: if you have
several pi-'s in your final state and some of them are hitting these
low-gain paddles then you may not get triggers.  It may have a larger
effect for eg3 than other experiments since you guys had the three
sector trigger.

  - Paul

On Jan 26, 2011, at 3:09 PM, Zhiwen Zhao wrote:

hi,Paul

When you are talking SC trigger efficiency, do you actually mean SC
efficiency?
I didn't really do SC eff study, but I did cut away some paddle with
low occupancy away as showed in the note.
Once I have looked g10's SC eff study, but it's takes a very different
approach from what you did and is more similar to a DC hit eff.
For your approach, I will need to study all kaon/pion/proton SC eff.
That's gonna be a lot of work.
With the large trigger eff correction of eg3, I hope SC eff will be
buried in the other big error bars.

Did you put your result into gpp? How about your pion and proton SC eff?

Zhiwen


On 01/26/2011 02:51 PM, Paul Mattione wrote:
> Hey Zhiwen, did you try to do a trigger efficiency study on the SC
> paddles? For g13, I found a lot of SC paddles that had really low
> triggering efficiency because they had low gain (old PMTs at max
> voltage
> but weren't replaced yet). For me, this mostly had an effect on
> pions at
> back angles.
>
> Old but "close enough" study plots (trigger efficiency of pi-'s with
> momentum > 400 MeV/c):
> http://clasweb.jlab.org/rungroups/g13/wiki_secure/index.php/PiMinusTriggerEfficiencyStudy#P_.3E_400_MeV
>
>
> - Paul
>
> On Jan 20, 2011, at 2:35 PM, Zhiwen Zhao wrote:
>
> Hi, folks
>
> I put up things related to the note at the page
> http://clasweb.jlab.org/rungroups/eg3/wiki/index.php/Analysisnote_Lambda1520
>
> which is linked from the main wiki page
>
> I has got comment from Kijun and Elton. More comments are welcome.
> Thanks a lot
>
> Zhiwen
>
>
> On 12/14/2010 02:20 PM, Zhiwen Zhao wrote:
>> Hi, folks
>>
>> I posted the Lambda1520 analysis note v3 on wiki and you can also
>> get it
>> directly from
>> http://www.jlab.org/Hall-B/secure/eg3/zwzhao
>> /analysisnote_Lambda1520_v3.pdf
>> This is for reviewing within eg3
>> Please send me your comment and I really appreciate it.
>>
>> Zhiwen
>> _______________________________________________
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