sPHENIX HCal discussion

["Kistenev, Edouard" <kistenev AT bnl.gov>]

Eric,

I second John, symmetry is the king in this case. 

Thought that maybe we could also make use of the fact that 8-channels cables are already on the table. Bringing all channels from IHCal in groups of 8 may(?) help the trigger. If 8 channels are 2x4 then combining two groups of 2x4 (4x4 trigger seed) from two neighboring sectors on a common 16 channel input connector to digitizer may save time in trigger computations (Chi will be happy to have and spend it). 

All the best and Happy New Year to everyone.

Edward

---

From: sPHENIX-HCal-l <sphenix-hcal-l-bounces AT lists.bnl.gov> on behalf of Lajoie, John G [PHYSA] <lajoie AT iastate.edu>
Sent: Tuesday, December 29, 2020 2:27 PM
To: Mannel, Eric <mannel AT bnl.gov>; sphenix-hcal-l AT lists.bnl.gov <sphenix-hcal-l AT lists.bnl.gov>
Subject: Re: [Sphenix-hcal-l] iHCal Interior signal cables

 

Hi Eric,

For my $0.02, I like keeping symmetry at the detector level so I would go with 24/24 and keep north/south ends together at that level.

John


John Lajoie
he, him, his
Professor of Physics
Iowa State University
 
(515) 294-6952
lajoie AT iastate.edu

-----Original Message-----
From: sPHENIX-HCal-l <sphenix-hcal-l-bounces AT lists.bnl.gov> On Behalf Of eric mannel
Sent: Tuesday, December 29, 2020 1:14 PM
To: sphenix-hcal-l AT lists.bnl.gov
Subject: [Sphenix-hcal-l] iHCal Interior signal cables

Folks-

Some time ago, we agreed that we would bring 24 signals out the north and 24 signals out the south end of the iHCal.  The implications of this are that we would need to run 1 16-channel and 1 8-channel cable from the iHCal and plug 2 8-channel iHCal channel cables into a singe connector on the digitizer board. This balances the cabling north/south.  An alternative would be to route 32 channels to one end and 16 channels to the other.  The implications here are which end do you route the 32 channels, all north or all south? 50/50 and hope you get all the modules correctly assembled and installed.  And just to be completely open, there is a small difference in timing.  For the case of
24 North and 24 south I estimate that the timing difference is going to be of oder 7 nSec or ~1/2 a digitizer timing bin. If we go with with 16 and 32 channels N/S then the difference will increase by by 3-4 nSec. For analysis, I don't think this is an issue, for triggering, again, I don't think it is an issue, but I just want it to be on the table.

The reason I am bringing this up is that Frank has sent me the lengths for the interior signal cables, and I want to place the order for cables and start assembly when they come in. Once I do that the choice is made.  It can be changed at the cost of dollars and time to redo cables.

I would like to get a consensus on which way to do it, so I can move forward next month with ordering cables and parts.

Eric


--
Eric Mannel, Ph.D.
PHENIX Group
Dept of Physics
Brookhaven National Lab.
631/344-7626 (Office)
914/659-3235 (Mobile)

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