sPHENIX tracking discussion

[Abhay Deshpande <abhay.deshpande AT stonybrook.edu>]

Hi All,

Sorry, I got distracted clearing the snow…. during the afternoon.

Sasha and I seem to be on the same plane. Indeed the momentum that we maximize the benefit from

the TPC is from the Jacque-Blondel method where the kinematic reconstruction occurs using the hadron’s

kinematics. I also agree with Sasha’s comment on the eta (up-to-2) reach for the electron side. Here I

must say, I need to think more, do not recall what we decided earlier. Sasha’s argument is logical, but can 

not say if that would be possible/practical or an alternate technology may help. I know there are some

interesting ideas are being pursued by the JLab folks. I will write more about this when I learn more.

Cheers, Abhay

-----------------------------------------------------------------

Abhay Deshpande
Professor, Department of Physics and Astronomy
Stony Brook University
Phone: +1 (631) 632-8109

Email: abhay.deshpande AT stonybrook.edu

Skype ID: adeshpande_at_sbu

On Feb 5, 2016, at 3:46 PM, Alexander Bazilevsky <shura AT bnl.gov> wrote:

Hi Tony, 

I just second to what Abhay commented - I haven't seen why TPC geometry should be different for HI and EIC (sorry if I missed some discussions on that). 
Probably one point to mention is that at EIC we intend to use TPC not only for central rapidity tracking but also for forward tracking, particularly in electron going direction (up to eta=2), where we may not have enough space to put a few more tracking planes between EMCal and TPC. So we may think about higher resolutions in inner TPC. 

... My 2 cents. 

Sasha. 

On 2/5/16 2:16 PM, Frawley, Anthony wrote:

Hi All,

My question was not whether there should be space for a PID detector in the EIC detector. Clearly there should.

My question was based on some early discussions I heard, where it was thought that the TPC geometry for the HI experiment and for the EIC would be optimized differently, so the field cage and gas vessel would be replaced, for the EIC detector but everything else would be reused. If that was the case, and the TPC would be replaced after sPHENIX, then it did not make sense that we have to limit the radial envelope of the sPHENIX version to make room for a PID detector that would only have to coexist with the EIC version of the TPC.

Of course if we plan to use the same detector for sPHENIX and the EIC detector, then it has to fit inside the PID detector for the EIC detector.

Cheers

Tony

---

From: sphenix-tracking-l-bounces AT lists.bnl.gov <sphenix-tracking-l-bounces AT lists.bnl.gov> on behalf of Alexander Bazilevsky <shura AT bnl.gov>
Sent: Friday, February 5, 2016 1:51 PM
To: sphenix-tracking-l AT lists.bnl.gov
Subject: Re: [Sphenix-tracking-l] Minutes of sPHENIX tracking meeting January 29, 2016

 

I think we did some simple evaluation of the TPC PID while preparing ePHENIX LoI (I can try to find it if necessary), and indeed the effect was marginal for a very simple reason - for DIS we're mainly interested in high z (hence high momentum) hadrons. However it may be more important for Jacque-Blondel approach (using hadron state) for DIS kinematics reconstruction. So, I think TPC will be important for both tracking and low momentum PID in ePHENIX. 

Sasha. 

On 2/5/16 11:38 AM, Mickey Chiu wrote:

Hi,

I haven’t seen any plots for the proposed TPC, but typically TPC PID extends out to only about 1 GeV, which as Abhay knows is way too limited for an EIC detector.  I think the 10 cm space should definitely be reserved for PID.  I know a group of PHENIXians working on R&D for a 10 ps TOF.  That work is going well and would fit in that space.  One could also consider a DIRC, but there are many issues with that approach which I won’t go into here.

One thing I would mention is that while I’m not sure which outer tracker we will have for sPHENIX, a silicon option would not be ideal for an EIC detector where one wants to minimize the material seen by the electron.  However, if it were designed to be reconfigurable, it could be reused nicely in the EIC detector.  One could, for instance, possibly place it as an outermost tracking layer (assuming there is enough space) which would take advantage of the L^2 in the tracking resolution.  One could also consider reusing it as part of a forward tracker.

Mickey

On Feb 5, 2016, at 11:14 AM, EdwardOBrien <eobrien AT bnl.gov> wrote:

    Hi Abhay,
     For now I think it best that we keep a 10 cm wide radial space set aside
     for an undetermined PID detector between the Tracker and EMCal, in
     the EIC era. In addition we'll need a small stay clear region front and back 
    to make installation possible and to take into account mechanical tolerances.

    Ed

On 2/5/2016 5:52 AM, Abhay Deshpande wrote:

Yes, true. But the TPC itself will serve us as a PID detector. We could further think of something thin beyond that if necessary. 

Cheers, Abhay

Sent from my iPhone

On Feb 4, 2016, at 6:51 PM, EdwardOBrien <eobrien AT bnl.gov> wrote:

    Dear all,
     The sPHENIX radial control envelop has a space beginning at 80 cm
    for an undefined future PID detector (EIC era). Presuming a stay-clear space
    between detectors of 2 cm that means the outer radius of
    the Tracker can reach to 78 cm, no further. The proposed design of the
    Si Tracker does not approach that radius but the TPC option would
    in principle reach that radius.

    Ed

On 1/29/2016 1:39 PM, Frawley, Anthony wrote:

The minutes of today's tracking meeting are below. The slides are posted at:

https://indico.bnl.gov/conferenceDisplay.py?confId=1719

Cheers

Tony

sphenix tracking meeting, January 29, 2016
---------------------------------------------------------

Itaru Nakagawa - strip tracker status:
-------------------------------------------------

Itaru reported on the status and future timeline of the strip tracker silicon R&D.

Ed: Can you send me a couple of slides outlining what you have done for R&D in last 6 months and what will happen in next 6 months. Useful to have this in hand if questions are asked.

Rachid: Can you send us the table of sensor characteristics so we can decide which ones are better? Helps to choose the testing order.

It will be early March for the next funding news - will learn then if we make the interview. Maybe April for the actual funding decision.

Rachid Nouicer - integration of the silicon pixels into sPHENIX:
----------------------------------------------------------------------------------

Slide 4: The outer tracking envelope is at 75 cm or 80 cm? Ed is still checking, will report later.

slide 6: How much do the sensors overlap in phi? We should start by using the same overlap as in the VTX, see slide 5 for the configuration.
Rachid will check that slide 7 has the same sensor overlap as the VTX. Mike: You may have to fiddle with radius to get the 12 sensors to fit nicely, but will need to check if the result satisfies all engineering stay clear boundaries.

What is the dead space at the end of each sensor? Rachid will check. Comment: the dead area around the edge depends on the chip. 
Mike: There are two questions - we need both the intrinsic dead areas and the dead pixel map for simulations.
With the dead area that exists in the pixels already, it may not make sense to worry too much about gaps between sensors.

We need to know how the number of active pixels that overlap at each gap in sPHENIX affects the momentum measurement at low momentum. Mike said we could use the VTX simulations and scale the bend by the magnetic field ratio. Remember that at some point we are ruled by multiple scattering.

Action item: Rachid will get back to us by email with an overlap geometry for the pixels, we will then do some crude estimates  of where the momentum measurement is affected. Note that every other ladder is staggered in radius.
 
Mike: At some point we need the GEANT 3 geometry ported to GEANT 4, so we can simulate the actual proposed configuration.

Tom Hemmick - Brief TPC update:
----------------------------------------------

Slide 3: Ed: do you need help from BNL? Tom: yes, need professional engineering to discuss details of how to do the machinable foam. Ed: bring Niv to BNL, set up a meeting with BNL engineers and experts. 

Tom: still trying to figure out which foam to buy. Four densities on the market, more expensive with density. Not sure if the lightest density foam will work. Ed: Mike Lenz has experience with foam. 

Mike McCumber - MAPS layers for sPHENIX:
-----------------------------------------------------------
Mike made a verbal report, but uploaded a few slides after the meeting. He reported on three areas that are being pursued.

Slide 3: LANL LDRD funding: Mike outlined the path and timeline. 

Slide 4: Exploring collaborations. Working hard on establishing ties with LBL now. 

Slide 5: Santa Fe MAPS cost and schedule workshop. Three day workfest to produce cost and schedule document for the inner tracker, and a full tracker option.

Discussion:
Ming is working on when the needed experts are available. Will define the workfest schedule around the schedule of experts (Luciano Musa, Leo Greiner, ... ).
Dave: An earlier date would be better. Does the request for CD0 in April mean this should be before April? Ed: the CD0 does not address the scope, so they are in principle not coupled. Comment: won't DOE want to have an idea of the scope before awarding CD0? 

Ed: What would the full tracker outer radius be? The outer radius with 1.5 T field would be 60 cm. With 1.4 Tesla it would increase to about 64 cm.
We were told by Luciano in his presentation that a CERN engineer thought the ALICE ladders would work without re-engineering at the increased radius. That opinion would need to be checked carefully.

Mike would like to get from Berkely the MAPS geometry in simulation, and hopes to do that when he visits LBL in two weeks.

Discussion of the review recommendation that we should focus on reusing the pixels. Ed commented that we do not have to follow the review, if we make a good case for not doing so.  In this case the response will be a document that outlines the MAPS plan and justification. The response would be needed by the time of the next review (probably next Fall?). We need to think about the time scale for preparing the document. The intended audience is Berndt Mueller and David Lissauer. 

Ed noted that there is a web page for review comments and responses. 

Dave: When do you think you can settle on a date for the workfest? Mike said they will push hard to get it defined in the next week.

---

From: Frawley, Anthony
Sent: Thursday, January 28, 2016 10:44 AM
To: sphenix-tracking-l AT lists.bnl.gov
Cc: Frawley, Anthony
Subject: sPHENIX tracking meeting Friday January 29 at 9:00 am ET

 

Hi All,

We will have an sPHENIX tracking meeting tomorrow, Friday January 29, at 9:00 am ET. The agenda page is:

https://indico.bnl.gov/conferenceDisplay.py?confId=1719

At present we are expecting to hear from:

Rachid Nouicer - Update on reused pixels integration

Tom Hemmick - TPC progress

If anyone else would like to add an agenda item, please let me know.

Tony

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Upton, NY 11973 Tel: 631-344-3712
Email: shura AT bnl.gov
-------------------------------------------------

-- 
Alexander Bazilevsky
Brookhaven National Laboratory, Bldg. 510D, 2-232
Upton, NY 11973 Tel: 631-344-3712
Email: shura AT bnl.gov
-------------------------------------------------

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