sPHENIX Event Plane Detector discussion

[Rosi Reed <rosijreed AT lehigh.edu>]

Some answers to these questions:

2. Broken spine - metal plate to support them -

The drawings are in process.  There are two parts to the frame for the sEPD, the overall frame and then the Strongback that the sEPD sectors will be clipped into.  We needed to make changes to the STAR design in order to stay under the cost envelope - namely changing the material from fiberglass to Al and to remove the pockets that the sectors would sit into.  I can send around the STAR drawings which are essentially 95% of the way there.

From looking at this, I don't think we need to add any additional plates to the scintillator, once they are held into the strongback they should be safe from movement.  The only issue would be if the break occurred before tiles 6 and 7 (assuming tile 1 is the point tile), which we do not have.

We will reglue the 3 broken sectors.  These will need to be checked for life before installation, but from the CO tests of SS01 it seems that a sector can operate just fine even with a break.  One would have to worry about damage to the fibers which is why we will reglue, in order to give them some more protection.

We will reglue the 2 sectors we have here at Lehigh this week, we have already made the reflective glue.  Once these are dry, either Tristan or Micah will drive them to BNL and pick up the 3rd sector in this condition so we can do the same with it.

The sector with the broken connector is not usable.  More details to follow.

Regards,

Rosi

On Mon, Jan 9, 2023 at 4:27 PM Ron Belmont <belmonrj AT gmail.com> wrote:

Hi All,

Here are the minutes from today’s meeting.  They’re numbered according to Jamie’s email below, which is also reproduced on the agenda page.

Regards,

Ron

*** The main action item is to get information, probably from Rosi, about the status of the SiPM boards, no later than tomorrow (Tuesday Jan 10).  We want to make a decision by this Friday (January 13) about when to resume cosmics testing. ***

1. Critical need for information, Tristan will ask Rosi ASAP (next 24 hrs)

2. Broken spine - metal plate to support them - how do we request drawings?  No engineered solution but Tristan will ask about that.  John Haggerty might know, worth asking him whenever someone runs into him.  Before we try additional plates we'll try adding more reflective epoxy (esp on s01).  Need more information about when installation will occur. Do we have cables? More information needed, shared with group.

3. Material scan in GEANT done.  Ejiro needs to talk to expert, then present.  2-d slice can help show whether support materials are there (e.g. silicon ladders).  Ejiro hoping to get it done this week and then send to list.

4. s10 broken? s01 and s14 at Lehigh to be repaired, s21-s30 at BNL (transported for collab meeting, waiting for cosmics)

a. sectors in cosmic stand at BNL s02-s09 (odd tiles tested for all), switch to even: inefficient, wanted to wait for more SiPM boards to come in to read out more channels

b. if we had an SiPM board that didn't have bad SiPM we'd save half time because we wouldn't do even vs odd?  two extra tests for shifted tiles.

c. could we test more than one at a time if we had more SiPM boards?  if we had 4 SiPM boards we could test four sectors even or odd or two sectors all tiles.  odd/even tiles go to two separate SiPM boards.  but not missing other things?  right.

d. nobody runnings cosmics right now because if we get SiPM boards soon because we'll be much more efficient; problem is we don't know when the boards are arriving... 

e. Colorado has more new people at the lab, and could start up again; big paddles have been returned

f. Not gonna have meeting on Monday because of federal holiday, need to have information about electronics and decision about cosmics by Friday (Jan 13)

Other: Dan talked to Eric to confirm he's on board with sEPD electronics plan.

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Ron Belmont (he/him/his)
RHIC/AGS Users' Executive Committee
Assistant Professor, Department of Physics & Astronomy
University of North Carolina at Greensboro
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On Jan 8, 2023, at 4:17 PM, Ron Belmont <belmonrj AT gmail.com> wrote:

Hi Jamie,

It’s completely fine with me, I’m not in EPIC and have no conflict.  All four of your points seem completely reasonable.  For point 3, I think it’s too short notice for a formal update, but it would be great if Ejiro can give a verbal report, and maybe a full report next week.

Agenda: https://indico.bnl.gov/event/18056/

Zoom: https://lehigh.zoom.us/j/99703618048?pwd=djFkNWNCSGk4dHlQRTdObkYwMXhKUT09 

Alternate zoom: https://uncg.zoom.us/j/95704655241?pwd=bjJqM01ZaUp0OFMvYWZPdmU4aS8xUT09 

I think the normal room works even if Rosi is not present.  We can fall back on the above alternative if that doesn’t work.

Regards,

Ron

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Ron Belmont (he/him/his)
RHIC/AGS Users' Executive Committee
Assistant Professor, Department of Physics & Astronomy
University of North Carolina at Greensboro
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On Jan 8, 2023, at 3:36 PM, Jamie Nagle <jamie.nagle AT colorado.edu> wrote:

Hello  Ron (cc sEPD list),

Thanks for the email.    Might I politely push back and see if we can have a short meeting.    

It  sends an odd vibe to cancel sEPD meetings -  where we have significant items to discuss and need to be ready to take data  in a  couple of months - for  EPIC meetings which is a different collaboration and a project a decade out.    

In particular,  I  would like  to hear about / discuss some open items.

1.   What is  the schedule for delivery of sEPD readout boards?      This  in particular has direct implications for completing the cosmic test data at BNL.     The tests would be much more efficient with more  boards, and also we would then have the  SiPM gains, which  makes the test results even more useful..

2.    We  had requested engineering drawings for the support of the sectors, and that was input to a discussion about  mounting sectors with broken "spines" -- those were never sent around.

3.    There was a nice study by Ejiro  on the sEPD occupancy, which feeds into questions for running and zero suppression.    There was an open question about what support / cables / services  material is in GEANT,  which  is what generates a lot of a hit background in the sEPDD -- directly impacting the occupancy.    An update here  would   be useful.

4.   You mentioned that the status of remaining sectors - seems worth going through the sector list and confirming the status of each.    Note that the last sector that was in Boulder arrived at BNL before the winter break, but likely needs to be re-wrapped -- this is the one that was broken when UPS opened the box at their facility in Utah.

Sincerely,

Jamie

||------------------------------------------------------------------------------------------
|| James L. Nagle   
|| Professor of Physics, University of Colorado Boulder

|| EMAIL:   jamie.nagle AT colorado.edu
|| SKYPE:  jamie-nagle        
|| WEB:      http://spot.colorado.edu/~naglej 
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On Sun, Jan 8, 2023 at 10:32 AM Ron Belmont <belmonrj AT gmail.com> wrote:

Hi All,

Since there’s a conflict with the EPIC council meeting, this week’s sEPD meeting is canceled.  Email updates are welcome.  It’d be great to know if the final sector has been received by BNL.

Regards,

Ron

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Ron Belmont (he/him/his)
RHIC/AGS Users' Executive Committee
Assistant Professor, Department of Physics & Astronomy
University of North Carolina at Greensboro
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Rosi Reed
RHIC/AGS UEC member
Associate Professor, Physics Department
Lehigh University
(610)758-3907
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