sPHENIX tracking discussion

["Yasuyuki Akiba" <akiba AT rcf.rhic.bnl.gov>]

Dear Tony,

 

What do you mean with preparation of tracking review? The topics you listed below seem to focus on a particular option of tracking. I remind you that there is no decision whatsoever is made on the technological choice of tracking. You should be open to all options and you need to be careful about the use of words.

 

I have a question on “event pile up”. What is your concern here. I suppose this is for p+p. The collision rate in AuAu in RUN16 was less than 10kHz in “narrow vertex” (|z|<10cm) except for the beginning of run so two collisions in one beam crossing is <0.1% within narrow vertex.

 

> Intermediate tracker
>      Do we need it to reconstruct pileup events?
>         Has to be settled by simulations before tracking review
>      What radius, configuration should it have to optimize performance?
>      What effect does its thickness have on mass resolution?

I want to point out that if you have a MAPS and 4 or more layers of strip layers, one can reconstruct tracks around the beam pipe. Such internal tracker is needed for b-jet tagging and heavy flavor measurement. You seems to concerned on the effect of the mass of silicon layers, but the study by your student last week has already shown that its effect is quite small for 1 layers of 4% radiation length at R=10cm. The effect should become even smaller for 4 layers of 1 % each at R=6,8,10,12cm as I proposed. And I think we can build such a silicon tracker from RIKEN internal funding alone.

 

As I wrote in my message for many times, tracks reconstructed in such a compact silicon tracker can be connected with hits of an outer tracker. Since you can use (1) positon (2) direction vector and (3) momentum for matching of the inner and the outer tracker, the gap between the two tracker can be quite large. And it is already demonstrated by a full Geant 4 simulation that combination of such a compact internal silicon tracker and a large outer tracker can achieve mass resolution to separate 3 Upsilon states.

 

In my opinion, your question “Do we need it to reconstruct pile up events” is a wrong one. A better question is “what is the best solution for the outer tracker used with a compact silicon tracker near the beam pipe.

 

Sincerely yours,

              Y. Akiba

 

 

From: sphenix-tracking-l-bounces AT lists.bnl.gov [mailto:sphenix-tracking-l-bounces AT lists.bnl.gov] On Behalf Of Frawley, Anthony
Sent: Thursday, July 21, 2016 3:02 PM
To: sphenix-tracking-l AT lists.bnl.gov
Subject: Re: [Sphenix-tracking-l] sPHENIX tracking meeting Friday July 22 at 9:00 am ET

 

Hi All,

 

I would like to focus in the tracking meeting tomorrow on preparations for the tracking review.

 

I made a list (below) of relevant topics that is likely not very complete. It would be good to expand it as needed, and to see where we stand on each item. Jin suggested that the MAPS ladder simulation would make the HF tagged jets case more convincing. We should discuss if we think this should be pursued for the review.

 

Cheers

Tony

 

Tracking prep for review
  Event pileup
      Event pileup generation
      Time dependence added in g4main and g4detector
      Revision of generator workflow, node storage in progress
      Needs multiple vertexing (RAVE)
  MAPS ladder code
      Completed code through creation of cell list
      Still need to update digitizer, live areas, thresholds, clustering
      Needs flexible tracker (GenFit)
      Need to make macro to run MAPS ladders + TPC
  TPC code developments
      Mike's rework of handling of uncertainties in TPC code should be done soon     
      What else is being done / needed on TPC code?
  TPC hardware
      How well do we understand the technical issues?
      What remains to be done before the tracking review?
      Cost and schedule status
  MAPS hardware
      How well do we understand the technical issues?
      What remains to be done before the tracking review?
      Cost and schedule status
  Intermediate tracker
      Do we need it to reconstruct pileup events?
         Has to be settled by simulations before tracking review
      What radius, configuration should it have to optimize performance?
      What effect does its thickness have on mass resolution?
         Being studied in cylinder cell geometry

 

 

 

 

---

From: Frawley, Anthony
Sent: Wednesday, July 20, 2016 10:35 PM
To: sphenix-tracking-l AT lists.bnl.gov
Cc: Frawley, Anthony
Subject: sPHENIX tracking meeting Friday July 22 at 9:00 am ET

 

Hi All,

 

We will have an sPHENIX tracking meeting at 9:00 am on Friday, July 22, at 9:00 am ET. The agenda page is:

 

https://indico.bnl.gov/conferenceDisplay.py?confId=2272

 

In addition to the status of the ongoing efforts, we should review our preparations and plans for the tracking review in September - not so far away!

 

Cheers

Tony