sPHENIX EMCal discussion

["Huang, Jin" <jhuang AT bnl.gov>]

Hi, Joe

 

Nice job! Thank you!

 

When you get time, the next thing we can do is to do a simple leading order position dependent correction, and see whether we can beat down the constant term:

 

1.       For the leading 8,12,16 GeV photon cluster cross all rapidity ranges, iterate through its constituting towers: TowerConstRange RawCluster::get_towers(), get energy and eta/phi ID of each tower

2.       Then calculate a simple energy weighted average position on the eta - phi bin ID grid (not actual eta/phi value as saved in the clusters).  

3.       Do a fmod (average bin, 2) for each eta and phi average bin ID. Then we have the effective shower center on a 2x2 SPACAL block (it is quite non-linear to truth position, but it is fine for the next step).

4.       Bin the energy response E_cluster/E_truth into 16x16 bins on the 2-D grid of [0-2] x [0-2] from step 3, this give us the position dependent energy correction as what we did in the test beam with 2-D hodscope grid.

5.       Use the above correction factor to correct for the observed cluster energy for all energy-point and EM shower species (e+/-, gamma).

 

If the result looks good (significantly lowers the constant term), we could write an reconstruction module to do such corrections for all EM shower clusters.

 

Cheers,

 

Jin

 

 

______________________________

 

Jin HUANG

 

Associate Physicist

Brookhaven National Laboratory

Physics Department, Bldg 510 C

Upton, NY 11973-5000

 

Office: 631-344-5898

Cell:   757-604-9946

______________________________

 

From: sPHENIX-EMCal-l [mailto:sphenix-emcal-l-bounces AT lists.bnl.gov] On Behalf Of Joe Osborn
Sent: Friday, May 26, 2017 3:38 PM
To: sphenix-emcal-l AT lists.bnl.gov
Subject: [Sphenix-emcal-l] Simulated Resolution of EMCal

 

Dear EMCalers,

 

As Jin presented in the simulations/EMCal meeting this week, he has updated the EMCal simulations with the tower tilting in azimuth and polar directions, amongst other changes. With the simulations code tagged, Chris produced single particle simulations that people can play with before we start producing large batches of simulations.

 

Attached are the resolution of the EMCal for photons, electrons, and positrons in several different eta bins. Just to be clear, the single particles were thrown for 9 different energies in the four different eta regions surrounding the values quoted in my plots (i.e. eta=0 corresponds to truth particles being thrown in +/-0.05 units of pseudorapidity around 0, same for eta=0.3,0.6, and 0.9).

Any comments would be great, or perhaps everyone will be too busy enjoying the long weekend in which case we can also discuss them at the EMCal meeting next week.

 

Thanks,

 

Joe 

 

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

 

Joe Osborn

Ph.D Candidate

University of Michigan

jdosbo AT umich.edu

(859) 433-8738