[Clas12_calcom] Calibration Challenge Report

Wed Sep 6 20:11:24 EDT 2017

Dear Dan,

I don’t think that I can follow exactly the format you are requesting and I don’t know if you can include the results I have in the report. The following is the status of what I am doing. We found out that the PMT/readout channel position is assigned on the wrong (opposite) edge of each strip; we will further confirm this with ECal geometry documents. We didn’t notice this for the KPP data (please see the example below) since the Tvertex which we got using information from FTOF dominated the Texpected+Tvertex term and Tvertex then was (positively) proportional to ECal’s TDC values. Of course, there was nothing wrong with the values we got from FTOF banks, but had the Tvertex behaved like a constant, like what we see now in our simulated data, back then we could have extracted a negative a1.

Correcting the readout channel position assignment, we get about 0.2 a1 (please refer to the example below), which is close to the expected 0.02345, but a2 of around 100, which is now, the negative inverse of the expected -108. 

In other words, with or without the mistake in readout channel position during the calibration of the KPP data, we could have extracted a positive a1 value because of the dominating correlation of Tvertex (which is independent to the effective length between the hit position and the readout channel) and TDC and this value can be re-extracted from the simulated data, even with a constant Tvertex, with the right readout channel positions. On the other hand a2, for which Tvertex has no significant effects, is more dependent on Texpected so “flipping” the readout channel’s position would likely flip the sign of of a2 and this is what we see after correcting the position. With the corrected readout channel position, a0 (we got 30) got nearer to the uploaded value of -10; since we do not have now higher order correction terms (those associated with a3 and a4), and we have a faulty a2 value, we are not expecting a0 value to be very close to the uploaded one.

Perhaps, I can only have input for items 3 and 4 of the requested list:

3. Issue encountered: negative correlation between Texpected and TDC values due to wrong assignment of readout channel positions. What was done: correction of readout channel position in the calibration code.

4. Plans: Recalculation of constants from KPP data.

Thanks,

Josh

> On Sep 6, 2017, at 7:33 AM, Daniel Carman <carman at jlab.org> wrote:
> 
> Folks,
> 
> We will not have a CALCOM meeting today related to the Calibration Challenge as 
> Raffaella indicated yesterday. However, I wanted to remind folks that by the end of 
> the day today we would like the feedback and results plots from each of the detector 
> subsystems that have completed their work for the Calibration Challenge. The request 
> information (and format) is given below from my original email from last week. Let me 
> know if you have any questions.
> 
> Regards,
> Daniel
> 
>> On Sep 1, 2017, at 2:27 PM, Daniel Carman <carman at jlab.org <mailto:carman at jlab.org>> wrote:
>> 
>> Folks,
>> 
>> Now that the second CALCOM Calibration Challenge exercise has (nearly) been
>> completed, we need to prepare a report over the next week or so to be entered
>> as a CLAS12-Note in advance of the upcoming Hall B Ready for Science (RfS)
>> review. To this end I would like each subsystem to prepare the following items:
>> 
>> 1). Set of comparison plots of calibration parameters vs. input parameters of
>> the form shown in CLAS12-Note 2017-002 (the first CALCOM Calibration Challenge
>> report) at:
>> https://misportal.jlab.org/mis/physics/clas12/viewFile.cfm/2017-002.pdf?documentId=37 <https://misportal.jlab.org/mis/physics/clas12/viewFile.cfm/2017-002.pdf?documentId=37>
>> Each subsystem should supply no more than 2 pages of plots.
>> 2). List of successes achieved during the challenge and list of those portions of the
>> calibration not studied as part of this challenge.
>> 3). List of problems and issues encountered (and what was done)
>> 4). Remaining calibration suite development plans.
>> 
>> I would propose that the subsystem teams provide me this material by Wednesday,
>> Sep. 6. The draft report will be circulated shortly after that time for final comments
>> before submission. Please let me know if you have any questions or if something
>> is not clear.
>> 
>> Regards,
>> Daniel
>> 
>> ***********************************************************************************
>> *                                                                                                                  *
>> * Dr. Daniel S. Carman                  e-mail : carman at jlab.org <mailto:carman at jlab.org>                     *  
>> * Staff Scientist                              office : (757)-269-5586                         *
>> * Jefferson Laboratory                   web: http://userweb.jlab.org/~carman <http://userweb.jlab.org/~carman>  *  
>> *                                                                                                                  *
>> ***********************************************************************************
>> 
> 
> 
> ***********************************************************************************
> *                                                                                                                  *
> * Dr. Daniel S. Carman                  e-mail : carman at jlab.org <mailto:carman at jlab.org>                     *  
> * Staff Scientist                              office : (757)-269-5586                         *
> * Jefferson Laboratory                   web: http://userweb.jlab.org/~carman <http://userweb.jlab.org/~carman>  *  
> *                                                                                                                  *
> ***********************************************************************************
> 
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