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<p class="MsoNormal">Hi Ashot,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Right now we have three experiments approved using essentially the same apparatus. After PAC51 it may become four, we all hope. We have to get all groups together after the PAC and discuss what should be done to make these experiments successful.
<o:p></o:p></p>
<p class="MsoNormal">As for calibration of HyCal, you are correct that in PrimEX and PRad we did gain matching using tagged photons. This was important because we used dynod signals for triggering while anode signals we digitized. The final energy calibration
(and signals) the tagged photons were not used but it was done using physics processes. In case of PrimEx it was pi0 and in case of Prad it was ep elastic and Moeller. With upgraded HyCal DAQ with flADC we are NOT splitting signal from each PMT. The exact
same information will be used in trigger and energy reconstruction in HyCal.<o:p></o:p></p>
<p class="MsoNormal">We still have to do gain matching but it can be done with cosmic. This will be sufficient to setup the trigger. The final energy calibration will be done the same way as we did in previous experiments with HyCal. I think it is important
to revisit the discussion of what is the best an most efficient way to calibrate our detectors. I am not ruling out tagged photon beam but we should see if this is something absolutely necessary, all pros and cons.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:black">-Eugene</span><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">PRad <prad-bounces@jlab.org> on behalf of gasparan--- via PRad <prad@jlab.org><br>
<b>Date: </b>Tuesday, July 11, 2023 at 12:19 PM<br>
<b>To: </b>Eugene Pasyuk <pasyuk@jlab.org><br>
<b>Cc: </b>Jingyi Zhou <jingyi.zhou@duke.edu>, prad@jlab.org <prad@jlab.org><br>
<b>Subject: </b>Re: [PRad] [EXTERNAL] Re: Presentation for the CLAS Collaboration Meeting<o:p></o:p></span></p>
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<p class="MsoNormal"><br>
Hi Eugene,<br>
<br>
Sorry for this late comment on your email, was traveling in last few<br>
days.<br>
<br>
Yes, one can colibrate the colorimeter/GEM system in different ways<br>
(as I also mentioned in my previous email). The only question is that<br>
we are planning a high precision cross section measurement that requires<br>
maximum detector performance. We used the same principle during the<br>
PrimEx and PRad experiment.<br>
As I remember, for the PRad-II experiment we developed and agreed on this<br>
subject, that is: (a) we use only T5 Tagger counter for a fast HyCal<br>
gain Equalizing and GEMs performance information. (b) after that we use<br>
3 short/small sections of the Tagger to have energy calibration, linearity<br>
check, and the HyCal efficiency measurement vs. position.<br>
<br>
These are our current agreement on the Tagger and we better to keep them<br>
as our plans unless somebody (including Ilya) presents and proofs a better<br>
plan for a High Precision Experiment(s).<br>
<br>
Hope we agree on our previous "agreements".<br>
Best,<br>
Ashot<br>
<br>
> Ashot,<br>
><br>
> It is possible to do pi0 calibration with untagged photons, or even with<br>
> electron beam. Ilya is evaluating this option, what is the optimal beam<br>
> energy to get the entire area covered.<br>
> We calibrate CLAS12 forward tagger calorimeter that way.<br>
><br>
> -Eugene<br>
> -<br>
>> -----Original Message-----<br>
>> From: PRad <prad-bounces@jlab.org> On Behalf Of gasparan--- via PRad<br>
>> Sent: Saturday, July 08, 2023 04:28<br>
>> To: Patrick Achenbach <patricka@jlab.org><br>
>> Cc: Jingyi Zhou <jingyi.zhou@duke.edu>; prad@jlab.org<br>
>> Subject: Re: [PRad] [EXTERNAL] Re: Presentation for the CLAS<br>
>> Collaboration<br>
>> Meeting<br>
>><br>
>><br>
>> Dear Patrick and Jingyi,<br>
>><br>
>> I would like to add few points on your comments/answers:<br>
>> 1) the Rsenblith plot is not "central" for our physics since we are<br>
>> not using in our FF extraction process. It can be easily removed<br>
>> from the presentation, you will only gain from that.<br>
>> 2) The "Tagger" issue was discussed during the PRad-II proposal several<br>
>> times. We better to have it partially operational for the GEM/HyCal<br>
>> calibration and HyCal equalizing process. For this we wanted to have<br>
>> the ~30% of Tagger focal plane detectors operational. In bad<br>
>> scenario<br>
>> we may also use tagger with a few T-counter open and use the pi0<br>
>> calibration. However, for the pi0 calibration we will need a solid<br>
>> target to insert it in the target area. This question needs further<br>
>> development.<br>
>><br>
>> Thanks,<br>
>> Ashot<br>
>><br>
>><br>
>> > Dear Jingyi<br>
>> ><br>
>> > I still believe that the plot is not very attractive. First, it is<br>
>> > based on a very old data set from the 1990s. Then, it is not very<br>
>> > intuitive to me why the reduced cross section normalized to the<br>
>> > squared dipole form factor should not be within a few percent from<br>
>> > unity, at least at low epsilon. At epsilon = 0, the reduced cross<br>
>> > section equals G_M^2 and the value on the y-axis equals (G_M/G_D)^2,<br>
>> > right? I believe one can easily produce a much more convincing plot<br>
>> from<br>
>> today's existing world data set.<br>
>> > The A1 data set, Bernauer et al., has Rosenbluth separations for 77<br>
>> > different Q2 values.<br>
>> ><br>
>> > I was referring to your label saying "Tagger" on p. 17, it gives the<br>
>> > impression that it is used in the measurement.<br>
>> ><br>
>> > Have a nice weekend,<br>
>> > Patrick<br>
>> ><br>
>> > ________________________________________<br>
>> > From: Jingyi Zhou <jingyi.zhou@duke.edu><br>
>> > Sent: Friday, July 7, 2023 15:17<br>
>> > To: Patrick Achenbach; prad@jlab.org<br>
>> > Subject: Re: [PRad] [EXTERNAL] Re: Presentation for the CLAS<br>
>> Collaboration<br>
>> > Meeting<br>
>> ><br>
>> > Hi Patrick,<br>
>> ><br>
>> > Thanks for your questions.<br>
>> ><br>
>> > The plot on page 4 is from Fig.3 of this paper, I added the reference<br>
>> > to the slides now.<br>
>> > <a href="https://arxiv.org/pdf/hep-ph/0612014.pdf%3chttps:/urldefense.proofpoint">
https://arxiv.org/pdf/hep-ph/0612014.pdf<https://urldefense.proofpoint</a><br>
>> > .com/v2/url?u=https-3A__arxiv.org_pdf_hep-<br>
>> 2Dph_0612014.pdf&d=DwMFAg&c=<br>
>> > CJqEzB1piLOyyvZjb8YUQw&r=DexAQjBL_LBq3J1v5tq-2pUGL-<br>
>> q3U3lNFJACyX2xBKA&m<br>
>> ><br>
>> =E_EYfRyweu3oKMK978wA9Tm_nYzjkM99u1ajkLgDfSn9CB9wOD1QEel7xDggrg<br>
>> 2h&s=ej<br>
>> > kZvtT8yGHmd3_8R2wNTNjWrDqn3Ic574InVqdmILw&e=><br>
>> > It is an example demonstrating the Rosenbluth separation technique.<br>
>> > Data points are shown for the Q2 values of 2.5 (open triangles), 5.0<br>
>> > (open<br>
>> > circles) and 7.0 (filled triangles) (GeV/c)^2 . The straight lines are<br>
>> > linear fits to the corresponding data points.<br>
>> ><br>
>> > I am confused about your question on p.17. I don't have any references<br>
>> > on p.17.<br>
>> ><br>
>> > I also changed that to "proposal" on p.23.<br>
>> ><br>
>> > Best,<br>
>> > Jingyi<br>
>> > ________________________________<br>
>> > From: Patrick Achenbach <patricka@jlab.org><br>
>> > Sent: Friday, July 7, 2023 2:40 PM<br>
>> > To: prad@jlab.org <prad@jlab.org>; Jingyi Zhou <jingyi.zhou@duke.edu><br>
>> > Subject: Re: [PRad] [EXTERNAL] Re: Presentation for the CLAS<br>
>> > Collaboration Meeting<br>
>> ><br>
>> > Dear Jingyi,<br>
>> ><br>
>> > thanks for the nice slides. I have a few comments:<br>
>> ><br>
>> > I don't fully understand your plot on page 4.<br>
>> > - Which data set is plotted there? Is this from PRad? No reference is<br>
>> > given.<br>
>> > - Why are the values between 7 and 9? Is this in per mille? The<br>
>> > differences of any cross section data form the standard dipole form<br>
>> > are maximum of 2-3 %.<br>
>> > - What is the Q2-value for the three different data sets?<br>
>> ><br>
>> > I also don't quite understand the references to the tagger on p. 17.<br>
>> > The tagger is not operational. I have not seen a request to upgrade<br>
>> > the tagger in the DRad proposal.<br>
>> ><br>
>> > On p. 23 I would call the DRad a "proposal", in line of what Ashot was<br>
>> > discussing.<br>
>> ><br>
>> > Best,<br>
>> > Patrick<br>
>> ><br>
>> > ________________________________________<br>
>> > From: PRad <prad-bounces@jlab.org> on behalf of Jingyi Zhou via PRad<br>
>> > <prad@jlab.org><br>
>> > Sent: Friday, July 7, 2023 14:06<br>
>> > To: prad@jlab.org<br>
>> > Subject: [PRad] [EXTERNAL] Re: Presentation for the CLAS Collaboration<br>
>> > Meeting<br>
>> ><br>
>> > Dear all,<br>
>> ><br>
>> > Thank you very much for your comments! Attached please find the latest<br>
>> > version of my presentation.<br>
>> ><br>
>> > Best,<br>
>> > Jingyi<br>
>> > ________________________________<br>
>> > From: PRad <prad-bounces@jlab.org> on behalf of Jingyi Zhou via PRad<br>
>> > <prad@jlab.org><br>
>> > Sent: Wednesday, July 5, 2023 6:42 PM<br>
>> > To: prad@jlab.org <prad@jlab.org><br>
>> > Subject: [PRad] [EXTERNAL] Presentation for the CLAS Collaboration<br>
>> > Meeting<br>
>> ><br>
>> > Dear all,<br>
>> ><br>
>> > Attached are my slides for the CLAS Collaboration Meeting. The talk<br>
>> > will be on next Friday (July 14th) at 10:05 am. It will be 20mins<br>
>> > presentation<br>
>> > + 5mins Q&A. Please let me know if you have any suggestions.<br>
>> ><br>
>> > Thanks,<br>
>> > Jingyi<br>
>> ><br>
>> > _______________________________________________<br>
>> > PRad mailing list<br>
>> > PRad@jlab.org<br>
>> > <a href="https://mailman.jlab.org/mailman/listinfo/prad">https://mailman.jlab.org/mailman/listinfo/prad</a><br>
>> ><br>
>><br>
>><br>
>> _______________________________________________<br>
>> PRad mailing list<br>
>> PRad@jlab.org<br>
>> <a href="https://mailman.jlab.org/mailman/listinfo/prad">https://mailman.jlab.org/mailman/listinfo/prad</a><br>
><br>
<br>
<br>
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PRad mailing list<br>
PRad@jlab.org<br>
<a href="https://mailman.jlab.org/mailman/listinfo/prad">https://mailman.jlab.org/mailman/listinfo/prad</a><o:p></o:p></p>
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