sPHENIX cold QCD topical group

[John Lajoie <lajoie AT iastate.edu>]

Hi Nils,

    Just a few comments -

- in the hadron-going direction ('right' in the drawing): The barrel EMCAL is not instrumented beyond the dashed-dotted white line of eta = 1.1 even though the EMCAl envelope extends further (it covers the readout). This means we have a range of pseudorapidities between approximately 1.1 and 1.45 without EMCal coverage. We might be able to recover this range by extending the barrel EMCal if we find it is necessary.

Of course, this gap is even worse if you limit the EMCal acceptance to 0.85.  All the simulations we did for the LOI use the forward EMCal acceptance picking up at 1.45.  If you try to extend coverage in the 1.1-1.45 gap you will have the Inner HCAL support structure in the way, so having an EM calorimeter there might not be very useful.

- in the hadron-going direction ('right' in the drawing): The sPHENIX engineering drawing still assumes a 30cm flux return 'door', while our forward-sPHENIX and EIC-sPHENIX studies have assumed only a 15 cm flux return. We need to agree on some number and move the forward-HCAL or decide we get rid of that flux return door and go back to using a magnetic hadron calorimeter (or get rid of the forward hadron calorimeter?).

The 15cm number was based on studies by Walt Sondheim at LANL. In principle BNL has engineering dedicated to the magnetic analysis for sPHENIX so they should be pushed to raise this issue in their engineering priorities.

It would be great if we could get sPHENIX to commit to a forward HCAL/flux return now and avoid the door entirely.  There may be a clever way of designing the steel so it could be instrumented (maybe as just the first longitudinal compartment) but calling it infrastructure, much as we are doing now with the barrel steel.

Regards,
John

On 4/18/2018 2:29 PM, Nils Feege wrote:

Hi Ming and all,

Attached is a screenshot of the sPHENIX + EIC detectors envelope drawings I discussed with the sPHENIX integration group last week. The boxes represent the areas reserved for detectors and their readout and some support, i.e. the actual sensitive areas are smaller and some additional required support structure is not included. The bright green boxes correspond to our latest 'EIC-sPHENIX' detector additions, while the other boxes are the sPHENIX envelopes.

Conflicts are wherever envelopes overlap, in particular:

- in the hadron-going direction ('right' in the drawing): What is not shown is e.g. the support structure for the TPC which, in the current design, extends from the TPC outer radius to the right all the way to the end of the inner HCAL, i.e. it goes right through the current gas RICH envelope. There might be ways to adjust the TPC support structure or have it limit the RICH acceptance only in some parts, not at all azimuthal angles. Also, the RICH envelope currently does not account for any support structure and readouts, so the actual acceptance for particle ID may be smaller.

- in the hadron-going direction ('right' in the drawing): The barrel EMCAL is not instrumented beyond the dashed-dotted white line of eta = 1.1 even though the EMCAl envelope extends further (it covers the readout). This means we have a range of pseudorapidities between approximately 1.1 and 1.45 without EMCal coverage. We might be able to recover this range by extending the barrel EMCal if we find it is necessary.

- in the hadron-going direction ('right' in the drawing): The sPHENIX engineering drawing still assumes a 30cm flux return 'door', while our forward-sPHENIX and EIC-sPHENIX studies have assumed only a 15 cm flux return. We need to agree on some number and move the forward-HCAL or decide we get rid of that flux return door and go back to using a magnetic hadron calorimeter (or get rid of the forward hadron calorimeter?).

- forward / backward tracking: The current locations of the GEM stations inside the TPC overlap with the MVTX and its support structure. It's not clear if we can fit any GEM discs inside the TPC inner radius with the MVTX present with its current design of support structure (which extends all the way to the end of the TPC as far as I understand).

- TPC envelope: The latest request for TPC envelope is even bigger than the one shown in the drawing, so we have even less space on either side. That includes readout cards and cables, so one solution may be to expect we'll be able to replace the TPC readout electronics in the EIC area with something that takes up significantly less space.

- electron-going direction ('left' in the drawing): It looks like we need to move the electromagnetic calorimeter in this direction further out to leave space for an mRICH or other particle ID detectors if we decide we need them. If we do, we'll get a gap in EMCal coverage around pseudorapidity of eta ~ -1.1 which will most likely be a problem. Maybe we can extend the barrel EMCal to recover this range.

If anyone has thoughts on this and wants to work on optimizing our detector design, please let us know! We could definitely use some help.

Best,

Nils

On Tue, Apr 17, 2018 at 2:14 AM, Ming Liu <ming AT bnl.gov> wrote:

Hi Christine and Nils, 

Could you elaborate a bit more on the possible conflicts/resolutions mentioned in the TG news?

Cheers 

Ming

Sent from my iPhone

On Apr 16, 2018, at 7:59 PM, Aidala, Christine <caidala AT bnl.gov> wrote:

Minutes:

 

Christine - TG News

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

As announced at the last sPHENIX General Meeting, the LOI charge from Berndt Mueller is now finalized.  A separate e-mail with the final charge will be sent out to the Cold QCD list shortly, as it was realized that this was never done. 

 

Following up on this, last Thursday Thomas Ullrich, who leads the EIC Working Group at BNL, held a discussion with Nils and Dave Morrison during the weekly EIC WG meeting on the simulation needs to fulfill the charge and how the EIC WG could help. 

 

On Friday, Nils, Mickey Chiu as the lead person for subsystem integration in sPHENIX, and Don Lynch as the chief engineer for sPHENIX, met to examine in detail the detector subsystem envelopes for the baseline sPHENIX detector.  Some conflicts were discovered with regions currently envisioned for EIC subsystems; possible resolutions are starting to be discussed.

 

 

Sasha Bazilevsky (BNL) – PHENIX-style clustering for (e, f, s)PHENIX EMCals

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

Clustering code based on PHENIX EMCal clustering.  Was implemented for sPHENIX Barrel EMCal a number of months ago.  Now implemented for EM calorimeters in both hadron-going and electron-going directions.  Should become part of standard simulation build in the next several days after approval by Chris/Jin, after which it will be available to everyone.  Energy and position resolutions shown for photons in the EEMC (electron-going direction).  Similar studies for electrons will need to include tracking.  Current geometry in GEANT is not projective, and not needed for hadron-going direction, but these studies conclude that projectivity is a must to fully utilize the high-resolution capabilities of the crystal EMCal in the electron-going direction. 

 

 

Enrique Gamez (Michigan) – Deeply Virtual Compton Scattering studies with EIC-sPHENIX

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

DVCS planned as the primary exclusive observable to be discussed in the LOI.  2014 LOI only included 2 DVCS plots: photon energy vs. pseudorapidity, and x-Q^2 coverage corresponding to different pseudorapidity ranges of the DVCS photon.  We need to update these with currently anticipated acceptances and decide what to include beyond this.  So far ASCII files for 500k 10 GeV x 100 GeV MILOU events provided by Salvatore Fazio of BNL EIC Working Group were translated into a Fun4All-readable tree and examined.  Basic kinematic distributions look as expected.  Next steps are to implement updated acceptances via angular cuts and/or GEANT, look at the distribution of electron-photon separation angles, and expand to a wider range of beam energies.

 

 

 

From: sPHENIX-cold-QCD-l <sphenix-cold-qcd-l-bounces AT lists.bnl.gov> On Behalf Of Nils Feege
Sent: Friday, April 13, 2018 3:05 PM
To: sphenix-cold-qcd-l AT lists.bnl.gov
Subject: [Sphenix-cold-qcd-l] Next sPHENIX Cold QCD TG meeting on Monday, April 16th, evening at 8:30pm ET

 

Dear Cold QCD enthusiasts,

 

our next meeting is scheduled for

 

Monday, April 16th, 8:30pm ET.

 

The meeting is BlueJeans only (https://bluejeans.com/345777492) with the agenda evolving at https://indico.bnl.gov/event/4539 with:

 

Sasha Bazilevsky - Clustering for EEMC Calorimeter in Fun4All / Geant4

Enrique Gamez - DVCS studies with EIC-sPHENIX

 

If you would like to present something (either at this meeting or at the next one on 4/30), please let Christine and me know and we will happily put your name on the agenda.

 

We look forward to hearing you at the meeting.

 

Best,

Christine Aidala & Nils Feege

Conveners sPHENIX Cold QCD Topical Group

 

--

Dr. Nils Feege

Research Assistant Professor

 

SUNY at Stony Brook

Department of Physics & Astronomy

Stony Brook, NY 11794-3800

 

e-mail nils.feege AT stonybrook.edu

skype nils1920

phone +1-631-632-8710

 

www.linkedin.com/in/nilsfeege

 

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Dr. Nils Feege

Research Assistant Professor

SUNY at Stony Brook

Department of Physics & Astronomy

Stony Brook, NY 11794-3800

e-mail nils.feege AT stonybrook.edu

skype nils1920

phone +1-631-632-8710

www.linkedin.com/in/nilsfeege

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John Lajoie

Professor of Physics

Iowa State University

 

(515) 294-6952

lajoie AT iastate.edu