[Clas12_calcom] [EXTERNAL] Re: new timelines for RGB available - ECAL check - feedback needed

[L Smith]

Silvia,

In my view it is more important to look at 8.5.0 vs 8.7.0 with the current calibration. There is already a SF parameterization in place for the first and second half of RGB.  In any case I don’t believe the PMT gains are stable below the 2% level, due to CAEN HV shifts and luminosity dependence (beam current ramping up and down or off for long periods), in addition to the overall slow gain drifts with time.  With this calibration the drift was reduced from 3% to 2%. 

Cole

> On Apr 13, 2023, at 9:41 AM, silvia--- via Clas12_calcom <clas12_calcom at jlab.org> wrote:
> 
> Dear all,
> new timelines for RGB S19 have been produced after the recent changes to
> CCDB for ECAL.
> They can be found at this link:
> https://clas12mon.jlab.org/rgb/pass0/v28.51/tlsummary/
> 
> I have made a comparison, restricted to ECAL, with the timelines done with
> the February cooking, please find my slides at the link:
> https://urldefense.proofpoint.com/v2/url?u=https-3A__box.in2p3.fr_index.php_s_ENtSbFexnzxfxS8&d=DwIFaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=qEkdYeiAbIsODpxTO59E_ab70KWmehf8Tr3XybSYmSs&m=qYQ-FcE6Mbby6RTYRCtAAjz6iTwPMPvdUKeFzKkJCvCL7m93EnGIOS9SVeMb6fyv&s=cZvgYQiuN6_U9-GaEpsPSbnwc0qLlJDvMZEQydl0hP8&e= 
> 
> There is an overall loss of electrons/trigger or roughly 2%, with the new
> reconstruction and CCDB.
> 
> I need feedback from Cole and CalCom in order to decide how to proceed.
> 
> Should we cook our 6 test runs to verify the performances? Or are further
> changes expected to happen to ECAL calibration constants or SF
> parametrizations (for both electrons and photons)?
> 
> In our RGB meeting of last week various possible tests were mentioned:
> - cook the 6 runs with the same CCDB timestamp (the old one or the new
> one, or both?) and the two versions of CJ (8.5.0 and 8.7.0)
> - cook the 6 runs with the same CJ and different CCDB timestamp.
> 
> What should we do?
> 
> Thanks a lot for your feedback.
> Best regards,
> Silvia
> 
> 
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