[G14_run] G14 work on TOF

[Franz Klein]

Reinhard,
the corresponding histograms display calculated versus detected flight 
time for pions and protons after a few cuts (e.g. momentum and dE in TOF 
paddle), for the detected flight time you have to know, of course, the 
velocity (for the way the code is set up, at least 1 good start counter 
time per event). I looked also at time offsets for 2-track events and 
they are consistent with my statement. If Haiyun corrects for the 'pion' 
offset for those run ranges and Jamie gets ST the timing aligned for 
protons and pions, there are only paddle2paddle offsets left for a few 
paddles. For the other cases (difference between proton and pion timing 
 > ~100-150psec), I suggest to redo the gmean calibration first.
Cheers,
Franz

On 08/14/2012 03:50 PM, Reinhard Schumacher wrote:
> Hello Franz,
>     I'm glad to see that you are back on line.  For the non-experts, 
> could you briefly explain how the ST timing can affect the SC 
> offsets?  I would have supposed that the timing of the SC is to the 
> RF-corrected tagger, and that the Start Counter plays little role in 
> the overall track timing.  But your comments indicate that this is not 
> the case, so could you explain that?
>
> Cheers,
> Reinhard
>
>
> ___________________________________________________________________
> Reinhard Schumacher         Department of Physics, 5000 Forbes Ave.
> Carnegie Mellon University, Pittsburgh, PA 15213, U.S.A.
> phone: 412-268-5177         web: www-meg.phys.cmu.edu/~schumach
> ___________________________________________________________________
>
> On 08/14/2012 02:11 PM, Franz Klein wrote:
>>
>> Haiyun,
>> overall the SC offsets in pass0/v5 look quite large for some run ranges!
>> This may be in part due to ST offsets, which differ between protons and
>> pions by -0.1 nsec ... likely due to poor timewalk correction for ST?!),
>> but also SC calibration (if proton and pion offsets differ a lot, check
>> gmean (and timewalk)):
>>
>> until run 68188 ~0.2 nsec for both proton and pion,
>> runs runs 68188-68305 ~0.2 nsec for pion and ~0.33 nsec for proton
>> (difference between proton and pion likely due to ST),
>> runs 68772-68779 ~0.19 nsec for pion and ~0.32 nsec for proton
>> (difference between proton and pion likely due to ST),
>> the next runs until 68998 poorly calibrated for ST and SC!
>> runs 69002-69044 ~ -0.28 nsec for pion and ~ -0.15 nsec for proton
>> (difference between proton and pion likely due to ST),
>> runs 69061-69113 ~0.42 nsec for pion and ~0.6 nsec for proton,
>> runs 69114-69147 ~0.22 nsec for pion and ~0.39 nsec for proton,
>> runs 69155-69369 and 69501-69597 have small absolute offsets but 100
>> psec difference between pion and proton (likely due to ST),
>> for 69370-69500 ~ -0.33 nsec for pion and -0.2 for proton (difference
>> between proton and pion likely due to ST),
>> runs 69604-69640 ~0.2 nsec for pion and ~0.37 nsec for proton.
>>
>> At this stage corrections for SC and ST depend a lot on each other
>> except individual paddles and large overall offsets: if you focus on
>> these and let Jamie work on ST, we should be in good shape.
>>
>> Greetings
>> Franz
>>
>> On Mon, 13 Aug 2012, Haiyun Lu wrote:
>>
>>> Dear Reinhard,
>>> I corrected all the runs with different offsets. Almost all runs
>>> should show very little offsets now. My corrections are based only on
>>> pions. The fact that the offsets are different for pions and the 
>>> protons
>>> is out of my control. It most likely links to some other 
>>> calibrations or
>>> corrections.
>>>
>>> Cheers,
>>> Haiyun
>>>
>>>
>>> _______________________________________________
>>> G14_run mailing list
>>> G14_run at jlab.org
>>> https://mailman.jlab.org/mailman/listinfo/g14_run
>>>
>>
>> ===============================================================
>> Franz J. Klein, Associate Professor
>> CUA, Department of Physics
>> Washington, DC 20064
>> office: Hannan Hall 206 phone: 202-319-6190
>> or: Jefferson Lab,CC F-243 phone: 757-269-6672
>> ---------------------------------------------------------------
>>

-- 
===============================================================
                   Franz J. Klein, Associate Professor
                   CUA, Department of Physics
                   Washington, DC 20064
   office: Hannan Hall 206          phone: 202-319-6190
   or: Jefferson Lab,CC F-243       phone: 757-269-6672
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