[G8b_run] inconsistent timing in EVNT and TBID/GPID

[Franz Klein]

absolutely! part of the wings (actually caused by our mod(2nsec) slicing 
of detector times) are always there when we run with high rates on the 
tagger, but the 'bad' thing was the 0.64nsec offset which caused that 
more particles were assigned to the neighboring beam bucket. 
Accidentally the 0.64nsec is just the photon flight time to cover the 
target offset of -20cm.
Sorry that I didn't catch this early on ... for g9 and g14 we used the 
same plots to check the quality (fitted values are kept in csql and 
monitor plots), but both targets were short (and centered close to the 
center of CLAS).

Cheers,
Franz

On 06/27/2013 03:07 PM, Barry Ritchie wrote:
> I realize it might be difficult to say at this point, Franz, but do you think these might have played some part in  generating some of the pronounced "wings" in the PID (beta v momentum) plots that Mike and Chuck saw (before applying other cuts)?
>
> Barry G. Ritchie
> Vice Provost for Academic Personnel
> Arizona State University
> 300 E. University Ave, Suite 420
> Tempe, AZ 85287-7805
>   
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>
> -----Original Message-----
> From: g8b_run-bounces at jlab.org [mailto:g8b_run-bounces at jlab.org] On Behalf Of Franz Klein
> Sent: Thursday, June 27, 2013 12:03 PM
> To: g8b
> Subject: [G8b_run] inconsistent timing in EVNT and TBID/GPID
>
> Hi,
>
> after running user_ana in the debugger a few times, I found a few wrong timing corrections in SEB and I made some updates in PID. Corrections in PID deal with finding the 'best event time' - using the more robust g12 code; the 2 changes in SEB correct the usage of RFoffset (was added
> twice) and photon time (was not corrected for target offset).
> As a result I relinked the original st2tof offset! And I started a few jobs on the farm to check the modified version in clasg9 account (which we use for g8b recooking).
>
> Now I go back to SC and TAG calibrations ....
>
> Cheers,
> Franz
>
> --
> ===============================================================
>                     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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-- 
===============================================================
                   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
---------------------------------------------------------------