sPHENIX tracking discussion

[Xin Dong <xdong AT lbl.gov>]

Dear All,

My internet connection got cut out near the end of today's meeting. I would like to throw out a couple of comments to follow up.

1) For the outside-in vs. inside-out, 

in the STAR's approach, as you know, originally there was only the TPC. The silicon detectors were added in later. So it starts from outermost layers of the TPC first and propagate inside for the occupancy reason. Later on when added the silicon detectors, although there are 4 layers, but one layer of strip detector has quite sizable fraction of dead channels. And the most inner MAPS layer is dominated by the pileup and UPC background hits (80% are background in MB AuAu events). So we didn't pursue further on the inside-out direction. And the tracker does first outside-in and then inside-out re-search.

In the sPHENIX case, the MAPS should be fast enough so that the background hit level is significantly reduced. Starting from inside may be a good option considering the occupancy.

2) I can see there are some good use of having the tracking with silicon layers alone in addition to the track seeding.

    - it will help with the TPC distortion correction check and use these track segments to improve the TPC calibration more conveniently. The level arm of the track segments will offer better sensitivities to separate offsets vs. rotations than just hit positions.

    - this also offers an independent measure of track multiplicities which is more immune to the pileup than TPC.

Please feel free to add more. Thanks

/xin

On Thu, Mar 9, 2017 at 8:05 PM, Frawley, Anthony <afrawley AT fsu.edu> wrote:

Hi All,

The agenda page for the meeting is:

https://indico.bnl.gov/conferenceDisplay.py?confId=2936

Cheers

Tony

---

From: Frawley, Anthony
Sent: Wednesday, March 08, 2017 4:47 PM
To: sphenix-tracking-l AT lists.bnl.gov; sphenix-software-l AT lists.bnl.gov
Cc: Frawley, Anthony
Subject: Targeted tracking meeting Friday March 10 at 9:00 am ET

 

Hi All,

There will be a tracking meeting on Friday March 10 at 9:00 am ET that will be focused on the upgrades to the tracking software that we discussed at the simulations meeting on Tuesday. We had 8 people volunteer during or after that meeting to work on upgrades to the tracking software, and this tracking meeting is aimed at getting that work started.

The topics that will be addressed are:

1) Replacing the pattern recognition. The current pattern recognition results in poor performance of the tracker, and is very slow. Christof had a proposal at the sims meeting for how to replace it.

2) We need to implement charge sharing for the MAPS detector.

3) We need the cluster precision problem for the INTT fixed (Gaku has committed a fix) and the results evaluated.

4) There has been good progress on the TPC simulation. Carlos will show slides on that.

Our goal will be to come out of the meeting with a well defined path to completion, with names attached to all asks.

Cheers

Tony

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--

===========================
Xin Dong
Nuclear Science Division
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road
Berkeley, CA 94720, USA
Tel: +1-510-486-4121
Email: XDong AT lbl.gov
===========================