sPHENIX tracking discussion

["Frawley, Anthony" <afrawley AT fsu.edu>]

Hi All,

The minutes of today's tracking meeting are below.

Cheers
tony

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The talks are posted at:

https://indico.bnl.gov/conferenceDisplay.py?confId=1578

Our guest speaker, Luciano Musa (MAPS expert) developed a last minute conflict, so we will have to reschedule his talk.

Mike - MAPS inner detector
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Discussion about how the cost of an all MAPS tracker might be reduced.
Tom:  It would reduce the outer radius if the middle layer was thinner. What if you swapped Al for Cu in the middle layer, could you get closer to 0.3% instead of 0.8%?
This is easy to test in simulations, will do.
Also, If the outer layer was a single layer (6 layer tracker) it would significantly the reduce cost. Six layers might be OK for the MAPS detector.

Ed: Is extending the ALICE ITS inner layer production feasible? Mike: will have to see how ALICE schedule works. They may be too early for us.

Ed: What is the source of $11M estimate for ITS? Draft of CDR.  Is everything in there? Mike will send a copy to Ed.

DR proposal is aimed at reaching the point where everything has been explored, and it is just a production project after that. The FEM design is an important add-on that we would need to provide.

If LDRD request is successful, when would money appear? Calls in January, proposal due March, 1st round done soon, defense, decision in July. Funding starts in October. There is a second review before they release funds. So latest about February of 2017, earliest would be October 2016, if the review could be hurried up.

There are no limitations on outside help, but do not know of a mechanism to send LDRD money outside of the lab.

Itaru - Schedule for silicon strip tracker
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Mechanical design: Ed: When are you next at BNL? December. Let's sit down with engineers and see if can get some momentum on mechnical design then.

Ed: What is the current thinking on getting the electronics design? Intend to rely on LANL. Ming: will use the same readout as for FPHX. Would be paid for by JSPS through RBRC.

Mike: When are you locked into a particular technical design? Need to make sure that physics performance is good enough before locking in.
Discussion: We are not yet at the point where we know what the physics performance will be. We need more effort on simulations to verify that what we settle on will do the job in central HI collisions. This includes understanding what tracking software changes would improve performance.
We should settle on a plan to resolve the remaining questions and modify the design as needed.
Tony: At the next simulations meeting (or ASAP), make a proposal with suggestions as to who does what.to resolve pattern recognition issues.

Ming: Is there a funding plan-B? Answer: if we do not get funding this year, we plan to assign money from operations to keep prototyping going, apply for JSPS again next year.

Tom: Cost & Schedule review recommended that tracker be part of the baseline. Ed: There are some subtleties in that. They recommend planning as if the tracker is part of the baseline project, but not necessarily adding the cost to the project. Ed said he can't see how to fund the tracker out of redirected RHIC ops, so there is a possibility we would be asked to descope other things to fund tracker if we do not get external tracker money. That would be bad. Ed thinks pursuing outside funding is critical.

Tom  - TPC project status (milestones and timelines)
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slide 10: The second line of electrodes is intended to smooth the field lines.

Sasha: where does the laser go? Tom: from the right, to shine on the central membrane.

Slide 14: Do you expect the circuit board to survive beyond the 1st spark? Tom: don't know. Want to test it.

Slide 13: is there a plan to make a prototype of a section of field cage for long term voltage testing? Yes, but only after testing of circuit board material to decide what thickness works.
Intend to make 4 sides of a square box (for convenience), at full length (1.6 m long) with actual material to be used in field cage.

Sasha - TPC R&D status (same slides as Tom's)
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Slide 18: This will will be used to understand how to control ion backflow.
The square GEM's are a feature, they allow easier offsetting of holes.

Slide 10: Sasha: plan to have electrodes between HPVF layers? No. The 5 mil layers are for isolation, assembly is already done by the company.
Would intermediate electrodes help? Tom: no - we will have essentially linear fields, so should not need stabilization. Essentially, it is a parallel plate capacitor.
Also, the voltage to ground is graded along the length so the electrodes would have to be bands.

Next meeting (December 4, 2 weeks from today):
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Next Tuesday does not work for Tom and Mike, so we agreed to ask Luciano Musa if he can come in 2 weeks to talk about MAPS detector.
Tom will make a presentation on ion backflow and space charge calculations.

We decided to ask Alan what is needed to get to where we can tell if we need an intermediate tracking layer between the TPC and pixels for central collisions. This would best be done in the simulations meeting, with a report back to the tracking meeting.