sPHENIX Event Plane Detector discussion

[Jamie Nagle <jamie.nagle AT colorado.edu>]

Hello Ejiro (cc same),

Thank you!   These updated numbers are very useful.    

It seems to me that trying to avoid zero suppression in the sEPD, particularly in the first year of running, is the best path forward.     Thus, if the Collaboration/Project/Day-1 Task Force decide to allocate boards for the sEPD, I think the configuration of 3 ADC boards per XMIT (for a total of 12 ADC boards and 4 XMITs) is optimal.   That should deliver up to 10 kHz without zero suppression, and if we need more rate capability, we can consider reducing the number of samples from 16 to 10 (for example). 

One other item on occupancy, is that it would be good to detail the material in front of the sEPD.    Often services from the silicon detectors, support materials, etc. have an incomplete description in GEANT.    Ejiro is there a way to follow up with Chris and maybe have a visual cross section of the material that is currently in place - and then labels on what things are going through with experts from the MVTX and INTT?

Sincerely,

Jamie

 

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

|| EMAIL:   jamie.nagle AT colorado.edu
|| SKYPE:  jamie-nagle        
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On Thu, Dec 15, 2022 at 8:31 AM Ejiro Umaka <ejironaomiumaka AT gmail.com> wrote:

Hi Jamie,

Here are some or all of the EPD information you requested (let me know if something is missing).

The plot of the MIP distribution and the occupancy distributions as a function of centrality can be found here:

https://github.com/eumaka/coresoftware/blob/master/simulation/g4simulation/g4detectors/macro/occupancy.pdf

A text file of the list of percentages for the16 different tiles going outward is here:

https://github.com/eumaka/coresoftware/blob/master/simulation/g4simulation/g4detectors/macro/tileoccupancy.txt

The source code used to pull this information is here:

https://github.com/eumaka/coresoftware/blob/master/simulation/g4simulation/g4detectors/PHG4EPDModuleReco.cc

The macro to run this is here:

https://github.com/eumaka/coresoftware/blob/master/simulation/g4simulation/g4detectors/macro/Fun4All_EPD_Analysis.C

The rootfile is here:

//sphenix/user/eumaka/sPHENIX/EPD/62run

Best regards,

Ejiro

On Thu, Dec 8, 2022 at 10:08 PM Rosi Reed <rosijreed AT lehigh.edu> wrote:

Hi Jamie and everyone,

I'm not sure how helpful this will be, but I have some data on this from the brief 200 GeV AuAu run done by STAR - this was essentially minbias triggered.  The MIP peaks were pegged to 160 ADC, so this doesn't quite reach 40%, but gets close and there was no evidence of a drastic change.  I can dig through my computer to try to generate it further if there is interest.   (The label should be Run 19, but it is indeed 200 GeV.)  There is zero suppression for ADC < 4.  The material budget shouldn't be completely different in this case. 

Rosi

On Thu, Dec 8, 2022 at 6:26 PM Ejiro Umaka <ejironaomiumaka AT gmail.com> wrote:

Hi Jamie,

Thanks! Chris has informed me that our newest mdc2 sample (run 62, type 4: min bias Hijing with 50kHz pileup) has 2.5M events available for this study. I'll keep you posted.

Thanks,

Ejiro

On Thu, Dec 8, 2022 at 5:32 PM Jamie Nagle <jamie.nagle AT colorado.edu> wrote:

Hello Ejiro,

Yes, exactly.    I was not sure if the geometry / response is the same as when that study was done.    Also, as you correctly not, having the exact Minimum Bias value for all 15 rings would be best.

For the most central events 0-10%, the occupancy is essentially 100% in all rings (as you noted on slide 4).

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 
||------------------------------------------------------------------------------------------

On Thu, Dec 8, 2022 at 10:41 AM Ejiro Umaka <ejironaomiumaka AT gmail.com> wrote:

Hi Jamie,

Thanks for your question. Looking through past studies, I noticed that you had done something close to this in the past (https://indico.bnl.gov/event/12501/contributions/52473/attachments/36192/59403/nagle_sepd_occupancystudy.pdf)

In particular, slide 4, middle plot (although it is a slightly different cut on the energy deposit/MIP distribution). Are you asking to do the same with a cut of (0.4* MIP) for a tile in the different 16 rings and retrieve an estimate of how many times hits fall beyond this cut? (The reverse (zero hits) can be inferred from the same estimate).

Thanks,

Ejiro

On Thu, Dec 8, 2022 at 10:29 AM Jamie Nagle <jamie.nagle AT colorado.edu> wrote:

Hello Ejiro and Brennan (cc to the sepd list),

Dan and I are going through the mapping of ADC boards into groups with XMIT transmitter boards.     In order to optimize the limited number of boards, it would be very helpful to have hit information from simulation for the sEPD.     Ideally, depending on radiation damage over time to the SiPMs, we would like to zero suppress below the single particle hit level (MIP). 

For Au+Au minimum bias collisions, can you provide a percentage for tiles for when they have >= 1 particle hit (based on cutting at 0.4 * MIP) and hence the percentage of the time a tile has zero hits.

Since this percentage will only vary radially, one can just have a list of percentages for the 16 different tiles going outward.

Thanks in advance,

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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Rosi Reed
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