sPHENIX HCal discussion

[pinkenburg <pinkenburg AT bnl.gov>]

    Hi Bill,
    
    the trigger information is available offline (it's in one of the
    streams). For the online monitoring which works on single streams we
    would need this information in every packet, which means the mode
    bits would have to be inserted into the packet header in the
    frontends. That functionality doesn't exist and it's not on top of
    the priority list. I have the feeling that we will definitely want
    this at least in pp. In PHENIX we decided to do the monitoring with
    MB events or at least some fixed trigger. I am pretty sure we will
    have luminosity dependent trigger downscales but if you take
    whatever comes any change in the trigger mix will affect the look
    and feel of the monitoring which will just confuse the shift crews
    (or involve a large folder of reference histograms for each trigger
    setting).
    
    In our sims we run with a 50kHz rate which is our maximum rate when
    running with the crossing angle. The problem is going to be how to
    identify a central event with the information in your single stream.
    While one can argue that a central event should fire all towers, you
    can only identify a central event by requiring that it fired all
    towers which leaves you with a chicken/egg problem. I guess one
    would argue that if a given tower hasn't seen a hit in 100 events a
    closer look at this tower might be warranted.
    
    just my 2c,
    Chris

On 7/18/2022 10:23 AM, W.A. Zajc via sPHENIX-HCal-l wrote:

      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   
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