sPHENIX HCal discussion

["W.A. Zajc" <zajc AT nevis.columbia.edu>]

Hi Justin:

Question and a comment:

The main new developement was that it was determined that it will indeed be too difficult  to put markers to directly identify LED events, so we should plan not to have those.  

Does this statement apply to offline, or just online monitoring? I assume LED’s fire according to some trigger that is recorded in the global data, correct?

For Hcal is it possible very central events might  have a decent probability of firing all 1500 towers in one event? 

Seems quite likely: for central collisions dN_ch / d\eta ~ 600 => dE_T / d\eta = 300 GeV => 3 GeV per tower (HCal). 

There should ~ 1+ kHz of such events if the Au+Au MB rate is 30 kHz, which is consistent with an (effective) luminosity of 5 10^27 /cm^2/s .

Here (effective) means “taking into account crossing angle” ; if I am wrong and the cited luminosity is for head-on collusions then there could be reduction in this rate.

Best regards,

Bill 

—————————————————

W.A. Zajc
I.I. Rabi Professor of Physics
Columbia University
New York, NY 10027

https://blogs.cuit.columbia.edu/waz1/
—————————————————

On Jul 18, 2022, at 9:03 AM, Frantz, Justin via sPHENIX-HCal-l <sphenix-hcal-l AT lists.bnl.gov> wrote:

Hi Hcal'ers,

I think a few of the hcal management folks have expressed that what I presented last week at the calo calibrations meeting for both calos seemed reasonable enough for the Hcal as well, with a few exceptions.   Since then there have been some further evolution at DAQ mtg and EMcal mtgs I wanted to share, plus just give an overall rundown so that we can  come to a consensus at tomorrow's calo calib mtg (10:30am), and then present that consensus at the Software meeting (which I can do but I would welcome any Hcal'er that is interesting in taking the lead on this to feel free to become involved even in what we present).  

The main new developement was that it was determined that it will indeed be too difficult  to put markers to directly identify LED events, so we should plan not to have those.   For EMCal it is presumed (although since John Haggerty was on vacation, there might not be FINAL confirmation on the possible LED firing patterns) that we can probably still identify LED events because "ALL"  towers in a ~sector will be fired during them.  For Hcal is it possible very central events might  have a decent probability of firing all 1500 towers in one event? which may hamper-- simply from multiplicity it seems possible...  (couple thousand particles per event in most central).   We should probably determine this rate, if anyone has data to confirm and measure the rate, I can check it in MDC2 Hijing maybe not by tomorrow.    Anyway, it's not necessarily that important to identify the LED events, I think the verdict is still out on that, and we will probably try to as much as possible, but we already also seem to have agreed on the other fast feedback monitoring methods TOO,  like rolling average hits per tower  ie  a map of this, that can serve to probe similar info.

So here is the current list of monitoring items (please comment or bring discussion to calo mtg tomorrow morning)  the things I've highlighted in red are unique for the Hcal, the other items are also envisioned for EMcal (e.g. could use common code)

Shift crew :

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

-like emcal monitoring in PHENIX

-2D Channel map (summative info based on below)

     -Tower hits /event   per tower based on rolling averges

     -Tower energy mean (or eqiuv) per tower (rolling avg)

          (whole spectra per sector?)

     -PIN diode data if in data stream?

      -whatever can be gathered from LED events if ID-able

      -temperatures, leakage currents, etc... ?   

      -timing t0 check per channel

 -text with out lying channel warnings

-total global energy in each (I&O) whole system per event

Expert  (Onl Mon based)

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

-mean pedestal for all towers (e.g. 2D map display) from peak extraction

-individual 2D Channel maps of above quantities

-Tower slope gain drift check per channel (? TBD)

-temperature , leakage currents, etc. NOT here

Separate gui -- Expert/ possibly some for "Voltage Operation Shifter" 

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

-temperature, leakage currents, etc.  from database.

With event-built events on SDCC fast reco pass (~2 hrs delay)

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

-Total ALL-calo energy per event

-Full tower slope fits

-Calibration items

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

Justin Frantz, Ph. D.  he 

RHIC UEC/Diversity Working Group 

Brookhaven National Lab, sPHENIX Experiment 

Associate Professor 

Ohio University Dept. Of Physics and Astronomy    

frantz AT ohio.edu    

646-228-2539   

PERSONAL ZOOM MEETING:  369-910-7530   Password:  1   

https://us02web.zoom.us/j/3699107530?pwd=TkZLeU1MY2d5eUpqeTJ5WUJTRHlVUT09

 

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