[Clas12_rgh] [EXTERNAL] CLAS coll. meeting

[Marco Contalbrigo]

Hi Nilanga,
sorry, I forgot to upload the last version. Now it is there.

Thank you for the additional study. I guess this rules out
an hypothetical instability due to the area-based scaling
factor, or the 1-photon threshold.

Looking to your table, one concludes that the resolution
is affected by length (L) but not by width (W), at least
within the explored range of values.

PANDA numbers suggest width (W) matters more than length
(L). MUSE is consistently below 100 ps, but shows
inconsistent trends: 65:87:67 ps for 4:5:8 mm wide
scintillator (with same SiPM and length). We might be at
their limit of precision.. indeed MUSE claims a systematic
error of 5 ps that may be optimistic (for example, one
should be sure the SiPM optical contact is the same
among the bars).

I assume resolution depends on the impact point of the
charged particle and is better for close than far
particles. Do you see this effect ? With sensors on both
sides, this may be mitigated. A sqrt(2) should be fine for
(at least) particles at the bar center. In case of PANDA,
the source may produce a beam with some divergence you
do not have though.

I suggest we postpone the fine comparison with PANDA,
and try to implement a digitization in coatjava to
support simulations. Your numbers souds reasonable
enough, and can always be improved.

Ciao, Marco.

On Thu, 6 Mar 2025, Nilanga Wickramaarachchi, Ph.D. via Clas12_rgh wrote:

> Hi Marco,
> 
> Thanks for including TOF time resolution results in your talk (though I don't see the slide in the file linked from agenda - can you upload the updated version please?)
> 
> To follow up on discussion from Monday RGH meeting, I have looked at the time resolutions again using a 3 mm x 3 mm sensor in simulation.
> The resolution results are shown in slide 2 of the attached.
> Also, the resolution values shown on Monday using scaling by cross section to 3 mm x 3 mm area are consistent with the values from 3 mm x 3mm sensor (slide 3)
> 
> I also see a trend of resolution getting poorer as the threshold number of photons increases.
> 
> It's not clear to me yet whether we need to scale the results by sqrt(2) to compare with the PANDA measurements.
> 
> Thanks,
> Nilanga Wickramaarachchi
> 
> __________________________________________________________________________________________________________________________________________________________________________________________________
> From: Clas12_rgh <clas12_rgh-bounces at jlab.org> on behalf of Marco Contalbrigo via Clas12_rgh <clas12_rgh at jlab.org>
> Sent: Thursday, March 6, 2025 7:11 AM
> To: clas12_rgh at jlab.org <clas12_rgh at jlab.org>
> Subject: [Clas12_rgh] [EXTERNAL] CLAS coll. meeting  
> Dear all,
> the draft slides of today's RGH presentation are available
> on the coll. meeting indico page. Any comments or
> suggestions are welcome, Marco.
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