[Rich] [EXTERNAL] draft of presentation at RICH 2025 workshop

[Marco Contalbrigo]

Ciao Marco,
thanks for the slides. The logic flow is nice.

slide 4: better remind here that the RICH complicated
design was dictated by the necessity to fit inside
the baseline CLAS12 (in substitution of LTCC) + a
containment of costs.

slide 5: rightmost panel in the bottom row has a
legend different from the others and less clear.

slide 6: it is not clear to what the "hundreds of plots"
refers. This is just reconstruction.

slide 10: this slide calls for a comparison with
simulation. The formula accounts for only the
un-correlated errors. There is a contribution from e.g. 
tracking and alignment that does not scale with sqrt(N).
I guess it is worth to specify. The 5 mrad expectation
seems in contradiction with the simulations in slide 17
(with values typically below 4 mrad).
At the time of TDR we expected somewhat around 4.5
mrad, accounting also for the aerogel "forward
scattering" (or surface effect) and Rayleigh (see Fig.
94 in TDR) that, I assume, are not yet in the simulations.

slide 15: I would add a bullet to say RICH improves
with respet CLAS (FTOF). Given the available quality
parameters mentioned in slide 13, RQ is just an example.
In the blue box I would write "The quality parameter".
Are we using the first spherical mirror row ? If yes,
I think is worth to mention as it is a distinctive
feature of CLAS12 RICH.

slide 19: calibrate -> calibration
Maybe one could explain the problem is that at
large plar angles, the number of possible patterns
(reflection sequences) for the photons emitted by
the *same* particle increases. A global approach that
accounts for all the mirror (and particles) at once
is therefore required. The selectin of specific
photon topologies as done with pass1 is not enough.
We have more distinctive information with pass2,
but it is not granted that could be enough (and
by sure will be human-time demanding). At this
point, AI could be more effective.

Bests, Marco.

On Wed, 10 Sep 2025, Marco Mirazita via Rich wrote:

> Hi all,
> next Monday I will give a presentation on the CLAS12 RICH at the RICH 2025 
> workshop.
> I uploaded a draft of my presentation on the RICH wiki:
> https://clasweb.jlab.org/wiki/index.php/RICH_Presentations  The talk will be 
> 20 minutes.
> Please let me know your comments by Thursday end of day.
> Thank you
> Marco
>
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