sPHENIX is a new detector at RHIC.

["Frawley, Anthony" <afrawley AT fsu.edu>]

Hello All,

I want to report back on my two homework items from my talk on MAPS ladder charge sharing at the sims meeting today.

1) I reran a check on the sensitivity of the cluster resolution to the charge sharing radius using 30 micron pixels, as requested by Jin. The results were:

diffusion radius far/near the diodes = 25/8 microns => 4.6 micron cluster position resolution

diffusion radius far/near the diodes = 35/12 microns => 4.7 micron cluster position resolution

diffusion radius far/near the diodes = 45/20 microns => 4.9 micron cluster position resolution

So the variation in cluster position resolution when varying widely from the default diffusion radius parameters of 35/12 microns is +4% and -2%. This supports my conclusion that the position resolution is insensitive to the diffusion radius parameters.

2) Chris reported at the meeting that the MAPS geometry object was occasionally returning negative pixel numbers - not good. I tracked this down to having the sensor sizes reversed for the inner and outer stave types in an "if-else", so that the geometry object thought our inner barrel sensors were smaller than they are in the gdml file. I fixed this and the negative pixel numbers went away.

Cheers

Tony

---

From: sphenix-software-l-bounces AT lists.bnl.gov <sphenix-software-l-bounces AT lists.bnl.gov> on behalf of Huang, Jin <jhuang AT bnl.gov>
Sent: Tuesday, March 14, 2017 4:36 PM
To: 'sphenix-software-l AT lists.bnl.gov'; 'sphenix-l AT lists.bnl.gov'
Subject: [Sphenix-software-l] [minutes] sPHENIX simulation and software meeting, Tue Mar 14, 1PM EST @ bluejeans

 

Minutes also available on agenda: https://indico.bnl.gov/conferenceDisplay.py?confId=2684

 

 

Single Photon Studies - Joe Osborn (U. Mich), Abinash Pun (Ohio U.)

 

Summary: Detailed investigation on response of 2-D projective EMCal on photon

 

Joe/Slide 5:

Jin: offset in eta comes may come from coordinate assignment of EMCal blocks. Default code assign the center of the block as the position of the block. On the level of detail at fraction of block width, one can improve by assigning the coordinate at EM-shower maximum depth as the position of the block. An convenient approach would be applying an offline recalibrator depending on the pseudorapidity of the photon.

 

Joe/Slide 6:

Jin: resolution shown here is similar to the simulation prepared for the pre-CDR and cost/schedule review. SPACAL simulation study has been stable

 

Joe/Slide 8-9: Zig zag position response VS truth position is observed. It leads to the double peak in position response.

Jin: expected structure as observed in test beam [ https://wiki.bnl.gov/sPHENIX/index.php/2017_calorimeter_beam_test/EMCal_runs_and_analysis#EMCAL3_third_position_scan_.280_degree.29 ], which we can in principal fit and subtract.

Jin: Gabor D. suggested using the log-scale energy weight instead of linear energy weight in order to correct for such non-linear position response. Need to find the energy scale used in the log-scale conversion that minimize the non-linearity.

 

Joe/Slide 12:

Chris: for the vertical irregular structure around phi_hCal = 90 degrees, expect some wrap-around problem that induced the problem at the phi = 90 degrees cut

Jin: we can cut on the off-trend events and investigate them. Will be happy to help.

 

Abinash/slide 4: zoom-in view of the low energy response location on one EMCal block, revealing features of fibers, sector boundary and tower boundaries

Chris: we will NOT see the fiber leakage in real life due to the random wavy of fiber in a real block. Simulation used ideal straight fibers for computational simplicity.

 

Jin: There is a revision of the EMCal engineering design in the next level of details as we speak. Preview of new features expected are

·       EMCal block will be tilted by 100-160 mrad away from perfect projection, which avoids the perfect projection of fiber and gaps. Slight non-projectivity is common feature among projective calorimeters to avoid non-uniformity around edges.

·       The EMCal block boundary and sector boundary are expected to be larger than the current model

 

Discussion:

Chris: with the current perfect projective EMCal model in Geant4, we can mimic this slight tilt effect by shifting the vertex location that photons are generated.

Jin: suggest shift by 15 cm, which is the expected value of tilt in the coming design.

Jin: Also suggest bring the talk to EMCal meeting 3pm EST on Tuesdays.

 

 

Exploring non-prompt D-meson b-jet correlations - Xuan Li

 

Summary: explore statistics of non-prompt-D and b-jet correlation from Pythia-8 simulation, which show a promising result.

 

Slide 5:

Jin: Double check parent z_j distribution of B-meson-b-jet correlation w.r.t. Ivan's paper [PLB, 750 (2015) 287-293]

 

Slide 8:

Jin: since there are enough statistics, we could separate in pT bins in central Au+Au collisions too.

 

Megan: is there cut induced drop at z_j around 0.7?

Xuan: form dropping of decay and pT spectrum?

Jin/Megan: suggest further suggest source of the cut off, e.g. by investigating the B-meson b-jet z_j spectrum that is the source of the D-meson b-jet correlation.

 

Jin: large statistics also allow us to investigate event plane dependence in a few phi-bins in the mid central event.

Jin: Suggest bring needs of D-meson trigger to Thu trigger meeting [ https://indico.bnl.gov/conferenceDisplay.py?confId=2943  ]

 

Plan: verify and produce statistics projection for MVTX proposal.

 

 

MAPS charge sharing simulation - Tony Frawley

 

Summary: a charge sharing model is implemented for the MAPS detector

 

Slide 3-4: Previous simple approximation need improvements.

 

Slide 5+: a charge sharing model was implemented based on arXiv:10053.3710

 

Jin: curious the dependence of diffusion parameters for 30 um-sized pixels.

Tony: #pixel per cluster look reasonable VS. thesis

 

Plan: Update proposal DCA plot with updated MAPS and INTT simulations.

 

 

Further discussions on tracking software

 

INTT clustering status

Christof : what is the status of INTT cluster offset debugging?

Tony: private discussion on-going debugging the INTT clusters on further debugging the secondary peak.

Chris: suggest separate INTT Cell reco from TPC Cell Reco code to avoid cross talks in development of very different detectors.

 

Cluster container TODOs

Christof : how to get clusters for a given later without iterate through all of them?

TODO item to implement fast layer fetching from the cluster container.

More tracking software TODO list to be discussion in the coming tracking meeting

 

 

______________________________

 

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: Huang, Jin
Sent: Monday, March 13, 2017 2:11 PM
To: 'sphenix-software-l AT lists.bnl.gov' <sphenix-software-l AT lists.bnl.gov>; 'sphenix-l AT lists.bnl.gov' <sphenix-l AT lists.bnl.gov>
Cc: 'sphenix-hf-jets-l AT lists.bnl.gov' <sphenix-hf-jets-l AT lists.bnl.gov>; 'sphenix-maps-l' <sphenix-maps-l AT lists.bnl.gov>
Subject: [reminder] sPHENIX simulation and software meeting, Tue Mar 14, 1PM EST @ bluejeans

 

Hello everyone,

 

We will have a sPHENIX simulation meeting to warm up the snowy Tuesday in the Northern US.

 

Currently on agenda is:

•         Photon+jet and photon simulations - Joe Osborn

•         D-meson b-jet correlation, a follow up to MVTX brainstorming meeting   - Xuan Li

Further topics will be welcomed too  

 

The agenda page is at https://indico.bnl.gov/conferenceDisplay.py?confId=2684  , for which the common modification password is "1008"

•         For residents at BNL, we will meet at the 2-219 conference room if not closed for snow

•         To join the Meeting via phone bridge:  https://bluejeans.com/619960505 

•         To join via Phone:

1) Dial:

        +1.408.740.7256

        +1.888.240.2560(US Toll Free)

        +1.408.317.9253(Alternate number)

        (see all numbers - http://bluejeans.com/numbers)

2) Enter Conference ID: 619960505

 

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

______________________________