[Erd108] ePIC Gaseous Detector DSL and DSTC

Sat Apr 15 18:00:29 EDT 2023

Hi Alexander,
Thanks for your feedback. Let me add some personal comment, but please keep in mind that a lot of the aspect of the DSC (not DSS 😊) are still a bit of not fully clear for me and what I am saying are just my current understanding which is probably not better than yours.

  *   You are right that MPGD trackers (hypothetical) in ePIC do not constitute a subsystem stricto sensu but this is the same for the Si layers… My understanding is that because of the nature of the ePIC tracker mostly MAPS technology everywhere complemented by MPGDs when necessary, it is better to have two separate groups MAPS-DSC and MPGD-DSC to allow experts in each technology to be included in the discussion because you don’t want for example a DSL for the barrel tracker who is a MAPS expect to be making decision regarding MPGD technology. Therefore this approach makes sense to me.

To which extent we can call it collaboration is not clear for me. It will still be, at least at the beginning an eRD108 like consortium but expanded to new groups and singularly focused on developing the technologies  relevant to ePIC detector needs.

  *   Regarding where MPGD layers are present in the current ePIC detector, I agree that for now, after the choice of imaging calorimeter as barrel EMCAL, the planar uRWELL behind DIRC are no longer part of the picture. My personal opinion is that. Regardless the number of imaging calo layers (4 or 6), if tracking behind DIRC is necessary to provide angular resolution information after the particle pass through to help the DIRC bars, I would argue that you need a second hit points in addition to the first tracking layer of the calo to provide a track.

  *   But actually, the real question is whether the DIRC folks need that information at all. We asked explicitly this question a couple of weeks ago to the DIRC people and their answer seems to imply that precision tracking before DIRC was what is needed ==> I will come back to this point later when addressing the barrel Micromegas layer. So planar uRWELL layer might not be needed not really because of the imaging calo tracking layer but because it is not crucial for DIRC. There is a similar lack of interest from the collaboration for an MPGD layer behind dRICH in the forward region that I also don’t understand.

  *   Additional MPGD discs in the forward and backward regions to provide tracking points and precision timing are been discussed and we (former tracking WG) are going to present the optimization of MPGD trackers options at the TIC meeting in the coming weeks.

  *   Regarding the current cyl. Micromegas in the barrel tracker, I have some real issues with the current design. I don’t know of any good argument (other than the available space) for having this layer at a radius 55 cm between the Si layers and the TOF layer which also is a precision tracking layer. It would make more sense in my view to me to move the layer(s) at a larger radius between TOF  and DIRC. This will combine the benefit of providing a better tracking capability (assumption) for the DIRC and less material (when we account for all services, support structure, cables and connectors) in the way of the Si tracker performance (momentum and DCA resolution) and still been mainly used for pattern recognition and precision timing for the overall tracker performance ==> We are also going to present this alternative option of swapping the order of AC-LGAD and MM to the TIC at the meeting.

  *   Last point, my view is that we need to focus our future effort in developing MPGD technologies that provide good performance (spatial point resolution > 150 um or more is not a good performance) and more  importantly are robust and resilient technologies  that can operate in a stable manner over the lifetime of ePIC ==> to do so, an eRD108 like consortium consolidated by new institutions with experience in these technologies should be the path toward forming the Detector Subsystem Collaboration (DSC).

I provide long answers to your questions because the optimization of ePIC tracker with MPGD layers has just actually started recently and there are a lot of questions that are still not answered to in the current geometry, that we need to quickly converge to

Any comment and feedback is welcome as whatever I said here are my raw personal opinion

Best regards
Kondo

From: Kiselev, Alexander <ayk at bnl.gov>
Sent: Saturday, April 15, 2023 2:42 PM
To: Kondo Gnanvo <kagnanvo at jlab.org>; erd108 at jlab.org; eic-rd-tracking-l at lists.bnl.gov
Cc: Seung Joon Lee <sjlee at jlab.org>; Huong Nguyen <htn3r.uva at gmail.com>
Subject: [EXTERNAL] Re: ePIC Gaseous Detector DSL and DSTC

  Dear Kondo,

  remind me please what DSS are we talking about. I mean the MPGD technology does not sound like a DSS to me, and eRD108 (as a project-funded consortium) either, even that the management plan tells us otherwise. As of yesterday a tracker behind the DIRC is seemingly gone, although it may not be true any longer with just four imaging EmCal layers. Endcap disks behind the silicon tracker look more than likely to me. Micromegas barrel is still alive, while uRWell barrel layers are questionable, right? Is there anything left behind the dRICH in the ePIC baseline configuration?

  Anyway, are we talking about an umbrella DSS governing all these possible (MPGD) subsystems, as proposed by the management? With a unified DSSL and just a single DSTC for e.g. a barrel micromegas and an endcap uRWell "real world Detector Subsystems"? How it is supposed to work in real life, if the former will probably be designed and built at Saclay, and the latter one say at FIT (and / or JLAB)?

  Cheers,
    Alexander.

________________________________
From: Eic-rd-tracking-l <eic-rd-tracking-l-bounces at lists.bnl.gov<mailto:eic-rd-tracking-l-bounces at lists.bnl.gov>> on behalf of Kondo Gnanvo <kagnanvo at jlab.org<mailto:kagnanvo at jlab.org>>
Sent: Friday, April 14, 2023 2:31 PM
To: erd108 at jlab.org<mailto:erd108 at jlab.org> <erd108 at jlab.org<mailto:erd108 at jlab.org>>; eic-rd-tracking-l at lists.bnl.gov<mailto:eic-rd-tracking-l at lists.bnl.gov> <eic-rd-tracking-l at lists.bnl.gov<mailto:eic-rd-tracking-l at lists.bnl.gov>>
Cc: Seung Joon Lee <sjlee at jlab.org<mailto:sjlee at jlab.org>>; Huong Nguyen <htn3r.uva at gmail.com<mailto:htn3r.uva at gmail.com>>
Subject: [Eic-rd-tracking-l] ePIC Gaseous Detector DSL and DSTC

Dear all,

I am assuming that you have all been following the new structure put in place for the ePIC collaboration that requires the formation of Detector Subsystem Collaboration (DSC) with a designated leader (DSL) and technical contact (DSTC). These two people are going to be representing the subsystem collaboration at the ePIC Technical and Integration Council (TIC) regular meeting

We would need to identify two people within our consortium (eRD108 and affiliates) So I would suggest if there are candidates for either role, please put your name in the ring and at some point we will find a way by next week to select the two people.  I am certainly putting my name for the DSL role.

We need to select the two people before the first TIC meeting on Friday 28 April.

Best regards

Kondo
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