sPHENIX HCal discussion

["Hodges, Anthony" <ahodges4 AT illinois.edu>]

Hi everyone, 

Here are the minutes from today's Calorimeter Calibrations meeting. They're somewhat lengthy as a decent bit of discussion was had. Feel free to email me if there is anything missing. 

Best, 

-Anthony

Begin Minutes:

• Shyam, Tower-by-Tower pi0 Calibration 

• Shyam recaps the previous work on this calibration by Justin, noting the intense statistical needs  

• The study is extended here by applying decalibrations in both phi and eta.  

• Not enough statistics from MDC2 for every tower to be calibrated, so the decalibration is made periodic in phi and eta, so regions with similar decalibrations can be stacked on top of one another. Calibration method converges within 7 iterations.  

• Megan: How are error bars calculated on slide 13 calculated? 

• Shyam: The first two have no errors bars, the others are the error on the mean value extracted via fitting 

 

• Part 2: investigating minimum energy cuts to try to simultaneously improve S/B ratio and maximize statistics.  

• Current minimum photon energy set to 1.1GeV, will investigate going down to 0.6GeV 

• Bill: For the sketch on slide 16, does the increase in statistical error at high energy come simply from low statistics at high energy? 

• Justin/Shyam: Yes, whereas the error at low energy is due to low S/B ratio. 

• Currently using estimator function for statistical error from previous PHENIX study, currently shows error decreasing at low energy, but no data points to constrain behavior.  

• Conversation between Craig and Justin about feasibility of mid-run calibrations. Primary concern is that calibration is very sensitive to statistics. Overall, will use the full statistics of the Run when calculating the EM scale calibration. Optimizing cuts to improve statistics is mainly to see at what point one can pull pi0 peaks during the run. Craig points out that this could be useful in looking at drifts in the pi0 peak which correspond to detector status. Anthony clarifies this could happen during the QA process that happens slightly downstream of the online monitoring. How far downstream "downstream" means is still up for discussion.  

 

• General Updates on HCal Online Monitoring by Blair 

• Code can call from client, fill, and plot 2D histograms. Also include warning messages with dummy thresholds.  

• Initial git push by Shuang.  

• Conversation about phi coordinates between Megan, Stefan, and John Haggerty. Original HCal sector numbering scheme used during installation now no longer used. JH clarifies that the new numbering scheme starts with phi = 0 (along the x-axis which is parallel to the ground), and ticks upwards from there. This is the preferred ordering, so no need to change anything.  

• Justin: Any change to sector numbering with HCal update? 

• Megan: Shouldn't be, will double check with Xiaochun 

• Plots shown on left are hits since beginning of run, right is running average of energy.  

• Justin: Eventually want to move towards what PHENIX had where the color codes correspond to different status codes (e.g. red = noisy, etc).  

• Anthony: You have to start with just filling these histos first though. Once you're happy with that, you can mask them however you want.  

• Discussion on running mean. Difficult to choose what quantities to track over time. Primary benefit of running mean is that it will show drastic changes to the detectors more quickly that single hit maps. 

• Blair has implemented quick running mean functionality into code. Anthony points out that Martin has ported PHENIX's running mean framework into the EMCal's repository. Blair will check it out and see what works better.  

• Maxim: Possibly want something other than a histogram to quickly track changes over the course of the run.  

• Justin: Not sure if there's anything but histograms within the server/client framework currently.  

• Also discussion about what databases currently exist and what/how much can be passed to/saved by them. Current understanding based on what's included as an example in the OnlMon repository.  

• Conclusion: Current hcal framework looks good, Blair and company will continue to provide updates.  

• Will also reach out to Tim about pulse fitting software. Maxim also chimed in to say a separate, faster system is being validated now. Might be worth comparing methods.  

• Justin: When and where should updates be posted? New work fest? 

• Anthony: Should definitely have another workfest, possibly on timescale of next CM. Post general updates to the software meeting, if calorimeter-specific problems arise, post in the calo-calibrations meeting.  

Anthony Hodges, PhD (he/him/his)

Postdoctoral Researcher

High Energy Experimental Nuclear Physics

University of Illinois Urbana-Champaign

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From: sPHENIX-software-l <sphenix-software-l-bounces AT lists.bnl.gov> on behalf of Frantz, Justin via sPHENIX-software-l <sphenix-software-l AT lists.bnl.gov>
Sent: Monday, August 8, 2022 9:44 PM
To: sphenix-hcal-l AT lists.bnl.gov <sphenix-hcal-l AT lists.bnl.gov>; sphenix-calibration-l AT lists.bnl.gov <sphenix-calibration-l AT lists.bnl.gov>; sphenix-emcal-l AT lists.bnl.gov <sphenix-emcal-l AT lists.bnl.gov>; sphenix-software-l AT lists.bnl.gov <sphenix-software-l AT lists.bnl.gov>
Subject: [Sphenix-software-l] Calo Calibrations Meeting Tomorrow Tuesday 8/9/22 10:30 am

 

Hi, 

Reminder again regular calo calibrations mtg tomorrow 8/9/2022  10:30am.    Shyam will go first giving his update on the pi0 Tower by Tower calibration and probably after myself will give some related updates.  Other than that, the agenda is open. Let me know if you would like to present.   

ZOOM Meeting info: 

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

indico:

https://indico.bnl.gov/event/16580/

and the zoom info: (same as before--it's a meet anytime)

Topic: sPHENIX Calibrations Meeting

https://bnl.zoomgov.com/j/1617635022?pwd=WmlVME9tcnlTYnlkUC9nU3crNTdRdz09

Meeting ID: 161 763 5022

Passcode: 503420

-Justin

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

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