[Clas12_rgh] [EXTERNAL] RGH meeting February 17

Mon Feb 17 13:34:12 EST 2025

Hi Marco,
Thanks for the questions and comments. Here are the answers to some of your questions.

------------------
Slide 2:
------------------

- What do you mean by "pixel": Is it a SiPM ?
In the geometry the sensor plane is segmented into 50 um x 50 um "cells" . So, a "pixel" is one of these "cells".

- You ask at least 10 photons, and take the time of
the first, is it correct ?
Yes, the event is required to have at least 10 unique pixels hit. Then I take the first photon (one with minimum time).

- Do you vary the impact position of the proton or
take just the middle of the bar ?
The impact position is fixed for all events (middle of bar).

------------------
Slide 3:
------------------

- Cherenkov radiation is prompt, scintillation is
slow. How can the second arrives earlier ?
I'm not entirely sure, maybe Cherenkov photon can arrive late since it's emitted at an angle?

------------------
Slide 5:
------------------

- The scale factor describes the fraction of detected
light. I am not sure it drives the resolution. Can not
you consider only the photons within the sensor
equivalent area ?
>From the simulation we found that the mean number of photons detected is proportional to ratio of areas considered for sensors and time resolution roughly varies as sqrt(number of photons).
In the current geometry sensor plane covers the entire cross section on one end of the bar.

------------------
Slide 6:
------------------

- What is the difference between coloumn 2 and 3: is
the 2 the first photon, and 3 the threshold time ?
Yes, column 2 is resolution from first photon (as in top plot in slide 3) and column 3 is using threshold time (as in right plot in slide 5).

- Which electronics are you considering ?

- In the last two rows, 10 mm is thickness or width ?
Row 4 is better than row 2, and row 5 is better than 3
while I would expect the contrary for wider tiles.
10 mm is the width of the bar.

You may consider also this benchmark:

T.~Rostomyan et al., {\it Timing detectors with SiPM
read-out for the MUSE experiment at PSI},
Nucl. Instrum. Meth. A 986 (2021) 164801.
Thanks, I'll take a look.

Regards,
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: Monday, February 17, 2025 11:52 AM
To: Nilanga Wickramaarachchi, Ph.D. via Clas12_rgh <clas12_rgh at jlab.org>
Subject: Re: [Clas12_rgh] [EXTERNAL] RGH meeting February 17

Hi Nilanga,
thank you for this interesting study. You are welcome to
present it next time. Meanwhile, let me ask you some
clarification:

------------------
Slide 2:
------------------

- What do you mean by "pixel": Is it a SiPM ?

- You ask at least 10 photons, and take the time of
the first, is it correct ?

- Do you vary the impact position of the proton or
take just the middle of the bar ?

------------------
Slide 3:
------------------

- Cherenkov radiation is prompt, scintillation is
slow. How can the second arrives earlier ?

------------------
Slide 5:
------------------

- The scale factor describes the fraction of detected
light. I am not sure it drives the resolution. Can not
you consider only the photons within the sensor
equivalent area ?

------------------
Slide 6:
------------------

- What is the difference between coloumn 2 and 3: is
the 2 the first photon, and 3 the threshold time ?

- Which electronics are you considering ?

- In the last two rows, 10 mm is thickness or width ?
Row 4 is better than row 2, and row 5 is better than 3
while I would expect the contrary for wider tiles.

I guess PANDA combines the sensors at both ends, i.e.
has a sort of 1/sqrt(2) improvement.

You may consider also this benchmark:

T.~Rostomyan et al., {\it Timing detectors with SiPM
read-out for the MUSE experiment at PSI},
Nucl. Instrum. Meth. A 986 (2021) 164801.

Ciao, Marco.

On Mon, 17 Feb 2025, Nilanga Wickramaarachchi, Ph.D. via Clas12_rgh wrote:

> Hi All,
>
> I uploaded a few slides on TOF timing resolution studies to the meeting wiki page.
> https://urldefense.com/v3/__https://clasweb.jlab.org/wiki/images/b/b2/RGH_Update_02_17_2025.pdf__;!!OToaGQ!tXRbmZcOYPNykUNU8A4sgAS_7InCzWaW1LBKllbJ-fWvsq1hvq38iKtO2iGZ8POJ_6aUqw-J8yFRYjMYpoMsLqGYJ40nXLSj$
> I can present it at the next meeting.
>
> Regards,
> 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: Sunday, February 16, 2025 4:11 AM
> To: clas12_rgh at jlab.org <clas12_rgh at jlab.org>
> Subject: [Clas12_rgh] [EXTERNAL] RGH meeting February 17
> Dear all,
> the next RGH meeting is scheduled for Monday
> February 17 at 8:00 am EST (2 pm CET).
>
> We will discuss the recoil status and plans
> for background studies.
>
> Please let me know if you are ready to present a
> contribution and be ready to upload it on the
> wiki:
> https://urldefense.com/v3/__https://clasweb.jlab.org/wiki/index.php/RGH_Meetings__;!!OToaGQ!qMC9F600sjSQKu3j2cz-W7cmU8LVgIqaw8glXNY07ROPiounVSgFCSwLxP0H9OTU5Hm_KK4gX5twu7pQ4UT3_OwhCpW-CPQm$
>
> Zoom connection details:
> ID 160 307 2676
> Code 273174
>
> See you there, Marco.
>
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