ATLAS Simulation/Reconstruction Software Reported by S. Rajagopalan work done by most US Institutes. U.S. ATLAS PCAP review Lawrence Berkeley National

ATLAS Simulation/Reconstruction Software

Reported by S. Rajagopalan Reported by S. Rajagopalan

work done by most US Institutes.work done by most US Institutes.

U.S. ATLAS PCAP reviewU.S. ATLAS PCAP review

Lawrence Berkeley National LaboratoryLawrence Berkeley National Laboratory

January 15, 2002January 15, 2002

PCAP review. January 15, 2003PCAP review. January 15, 2003S. Rajagopalan ATLAS Simulation & Reconstruction SoftwareS. Rajagopalan ATLAS Simulation & Reconstruction Software 2

Outline

Simulation/Reconstruction Activities:Simulation/Reconstruction Activities:(mostly by physicists)

Subsystems with US participation:

Pixels, TRT, EM Cal, Forwad Cal, Tile Cal, Muons, Trigger

In addition, extensive participation in combined reconstruction, test

beam software and physics analysis.

Well integrated into overall ATLAS computing effort.Well integrated into overall ATLAS computing effort. In particular, the US core efforts on Athena and DB.


ATLAS Subsystem/Task Matrix

US responsiblesUS responsibles

Being vacatedBeing vacated

Offline Offline CoordinatorCoordinator

ReconstructionReconstruction SimulationSimulation DatabaseDatabase

ChairChair N. McCubbinN. McCubbin D. RousseauD. Rousseau A. Dell’AcquaA. Dell’Acqua D. MalonD. Malon

Inner DetectorInner Detector D. BarberisD. Barberis D. RousseauD. Rousseau F. LuehringF. Luehring S. Bentvelsen /S. Bentvelsen /D. CalvetD. Calvet

Liquid ArgonLiquid Argon J. CollotJ. Collot S. RajagopalanS. Rajagopalan M. LeltchoukM. Leltchouk H. MaH. Ma

Tile CalorimeterTile Calorimeter A. SolodkovA. Solodkov F. MerrittF. Merritt V.TsulayaV.Tsulaya T. LeCompteT. LeCompte

MuonMuon J.ShankJ.Shank J.F. LaporteJ.F. Laporte A. RimoldiA. Rimoldi S. GoldfarbS. Goldfarb

LVL 2 Trigger/ LVL 2 Trigger/ Trigger DAQTrigger DAQ

S. GeorgeS. George S. TapproggeS. Tapprogge M. WeilersM. Weilers A. Amorim /A. Amorim /F. TouchardF. Touchard

Event FilterEvent Filter V. VercesiV. Vercesi F. TouchardF. Touchard


Software Activities Summary

Recent simulation and reconstruction activities have been geared Recent simulation and reconstruction activities have been geared

toward:toward:

High Level Trigger (HLT) Technical Design Report (due summer 2003)

G4 physics validation

Validation of C++ reconstruction software

Data Challenges (DC1 ongoing)

Test beam analysis

Physics studies by various groups


Geant3 simulation software

P. Nevski (BNL) is the ATLAS coordinator for the G3 effort.P. Nevski (BNL) is the ATLAS coordinator for the G3 effort.

Recent Activities include:Recent Activities include:

First revision of geometry since Physics TDR Latest geometry of the Inner Detector (incertable pixels, 2/3

layer variation, strip tilt inverted to minimize cluster size, realistic R/T in TRT)

Service Material updated Calorimeter: gap between barrel and endcap calorimeters

introduced readout of calorimeters updated (including 5 sample

digitization) dead material of the calorimeter readout updated Muon layout modified to latest geometry, digitization updated Optimised pile-up procedure allowing up to > 1k events to be

added


G4 Simulation activities (Pixel)

Pixel Simulation (D. Costanzo et. al., LBNL)Pixel Simulation (D. Costanzo et. al., LBNL) Pixel Geometry: Primary numbers from MySQL database

(used also by Geant3)

Geometry descriptions in GeoModel MisAlignments handled by new Athena Services


Material (Pixel) in G4


TRT Simulation

F. Luehring (Indiana) is the ATLAS TRT software coordinator.F. Luehring (Indiana) is the ATLAS TRT software coordinator. (and member of the TRT steering group)

Athena Pile-Up Requirements documentation ATL-SOFT-2001Athena Pile-Up Requirements documentation ATL-SOFT-2001

GEANT4 code writingGEANT4 code writing TRT hit and digitization definitions

Tabulation of material in the TRT detectorTabulation of material in the TRT detector And its appropriate include in G4 simulation

Studies of effect of Pile-up in TRT detectorStudies of effect of Pile-up in TRT detector


LAr Simulation

ATLAS LAr simulation coordination: M. Leltchouk (Nevis)ATLAS LAr simulation coordination: M. Leltchouk (Nevis)

Participation in G4 EM barrel developmentParticipation in G4 EM barrel development Integration of the LAr Simulation code in G4 architectured by Bill

Seligman : Used as templated by EM, HEC, FCAL.

LAr EM calorimeter hits (LArEMHit) were implemented in GEANT4

by B.Seligman.

Integrated with Athena Framework providing Root based persistency

to G4 Hits and using them for subsequent

Digitization/Reconstruction


GEANT 4 LAr Simulation


G4 Validation

compare features of interaction models with similar features in compare features of interaction models with similar features in the old Geant3.21 baselinethe old Geant3.21 baseline

try to understand differences in applied models, like the try to understand differences in applied models, like the effect of cuts on simulation parameters in the different effect of cuts on simulation parameters in the different variable space (range cut vs energy threshold…);variable space (range cut vs energy threshold…);

use available experimental references from testbeams for use available experimental references from testbeams for various sub-detectors and particle types to determine various sub-detectors and particle types to determine prediction power of models in Geant4 (and Geant3);prediction power of models in Geant4 (and Geant3);

use different sensitivities of sub-detectors (energy loss, track use different sensitivities of sub-detectors (energy loss, track multiplicities, shower shapes…) to estimate Geant4 multiplicities, shower shapes…) to estimate Geant4 performance;performance;

tune Geant4 models (“physics lists”) and parameters (range tune Geant4 models (“physics lists”) and parameters (range cut) for optimal representation of the experimental detector cut) for optimal representation of the experimental detector signal with ALL relevant repects;signal with ALL relevant repects;


G4 validation comparisons

Muon energy loss and secondaries production in the ATLAS Muon energy loss and secondaries production in the ATLAS calorimeters and muon detectorscalorimeters and muon detectors

Electromagnetic shower Electromagnetic shower simulations in calorimeterssimulations in calorimeters

Hadronic interactions in tracking Hadronic interactions in tracking devices and calorimeters devices and calorimeters

(Different showering models

in Geant3 and Geant4)

Reconstructed Energy [GeV]0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

Reconstructed Energy [GeV]

Δ e

vents

/0.1

GeV

[%

]Fra

ctio

n e

vents

/0.1

GeV

10-4

10-3

10-2

10-1

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Eμ= 100 GeV, ημ ≈ 0.975


G4 Validation (continued)

Geant4 can simulate relevant features of muon, electron and Geant4 can simulate relevant features of muon, electron and pion signals in various ATLAS detectors, often better than pion signals in various ATLAS detectors, often better than Geant3;Geant3;

Remaining discrepancies, especially for hadrons, are being Remaining discrepancies, especially for hadrons, are being addressed and progress can be expected in the near future;addressed and progress can be expected in the near future;

ATLAS can has a huge amount of the right testbeam data for ATLAS can has a huge amount of the right testbeam data for the calorimeters, inner detector modules, and the muon the calorimeters, inner detector modules, and the muon detectors to evaluate the Geant4 physics models in detail;detectors to evaluate the Geant4 physics models in detail;

feedback loops to Geant4 team are for most systems feedback loops to Geant4 team are for most systems established since quite some time; communication is not a established since quite some time; communication is not a problem;problem;

Few people in US involved in G4 validation studies Few people in US involved in G4 validation studies I don’t think anyone from US is a member of the G4 team


Sub-System Reconstruction

Extensive involvement by US people, primarily in:Extensive involvement by US people, primarily in: LAr, Tile and Muon reconstruction Combined reconstruction: egamma, Jets, tau’s and MissingET

The overall reconstruction chain is functional, a lot of the fortran The overall reconstruction chain is functional, a lot of the fortran code has been rewritten in C++, albeit several missing pieces code has been rewritten in C++, albeit several missing pieces and far from perfect.and far from perfect.

Most of the effort is focussed on:Most of the effort is focussed on: Validation Calibration issues Test Beam Analysis Standardizing the EDM and Detector Description usage


Database/Detector Description

Support for ROOT persistency for current Detector Description & some Support for ROOT persistency for current Detector Description & some Event Data Objects (Hong Ma, BNL who also coordinates ATLAS LAr Event Data Objects (Hong Ma, BNL who also coordinates ATLAS LAr database activities)database activities)

LAr Database/Detector Description activitiesLAr Database/Detector Description activities

Designed interfaces for accessing conditions data in Athena. Implemented interim solution for conditions data in MySQL for MC simulation, reconstruction, and some testbeam analysis.

Provide requirements input to ATLAS Conditions DB development

Detector Description: 2-day workshop at BNL (12/16/02) to discuss the adoption of the new Detector Description Architecture in LAr Simu/Rec.

Tile Database activities coordinated by Tom Lecompte (ANL)Tile Database activities coordinated by Tom Lecompte (ANL)

Similar activities as those for LAr.

Muon database and detector descriptionMuon database and detector description

XML detector description: MDTs, RPCs, TGCs implemented

Identifier scheme for Muons implemented by Goldfarb, Assamagan


Calorimeter Reconstruction

Liquid Argon : Liquid Argon : H. Ma, S. Rajagopalan (BNL), P. Loch (Arizona)H. Ma, S. Rajagopalan (BNL), P. Loch (Arizona) Tile Calorimeter : Tile Calorimeter : A. Gupta, F. Merritt (Chicago)A. Gupta, F. Merritt (Chicago) Combined Calorimeter Data Classes and AlgorithmsCombined Calorimeter Data Classes and Algorithms

SimulationSimulation OnlineOnline OfflineOfflineReconstructionReconstruction

CombinedCombinedReconstructionReconstruction

LArHitLArDigit

LArRawCaloCell

CaloTower

CaloClusterTileHitTileDigit

TileRaw

SimpleTrack

egamma

ProtoJet/Jet

tauObject

MissingET


1MB at t=0+ 25 bunch crossings with10 interactions each

(E not corrected for sampling fraction)

Expected elec. noise reduction from optimal filtering

Pile up increase

(note: OF coeff used are the sameIn real life, they will change with luminosity

Middle SamplingEM Barrel


Recent Plots using LAr recon. program


ATLAS Muon Software J. Shank (Boston U.) is the overall software coordinatorJ. Shank (Boston U.) is the overall software coordinator

Muon Database activities coordinated by S. Goldfarb (Michigan)

Current activity:Current activity: OO muon reconstruction (Moore) development

Contributors: G. Stavropolous (LBNL), K. Assamagan (BNL)

Integrated into Athena; in repository; in early development

Migration to new Event Data Model

Clusterization for MDT and CSC completed

Makes use of common track fitting and data classes with InDet Reco

Material Integration Service being implemented Muon database and detector description

Conditiond DB and Athena Testbeam work for the April run. J. Rothberg (U. Wash)

Identifers & detector description by Goldfarb, Assamagan


ATLAS Muon Database Contributions

Descriptions of Barrel Toroid (left)

and H8 test beam geometry (below).

Both geometries were generated using

compact AGDD syntax and both were

developed by REU summer students,

under the supervision of S. Goldfarb.


Raw Data Flow

Raw Data Flow Model establishedRaw Data Flow Model established London Meeting: (D.Quarrie & S. Rajagopalan met with London Meeting: (D.Quarrie & S. Rajagopalan met with

HLT to discuss their software design) HLT to discuss their software design) Established strategy on use of Athena/StoreGate in HLT

Data Converters (Hong Ma, BNL): Data Converters (Hong Ma, BNL): Simulation of ROB data and establishing relevant services ByteStream Raw Data and Calibrated Objects for use in

L2, L3 coordinated across all sub-systems by Hong Ma (and implemented for Liquid Argon)

Being implemented for Muons (K. Assamagan, BNL) Efficient on demand access to data in Regions of Interest


Simulation Data Flow

Generator McTruth(Gen)HepMC

ROD EmulationAlgorithm

L1 Digitization

Particle Filter Simulation

PileUp

McTruth(Sim)HitsROD Input

Digits

McTruth(PileUp)

DigitizationRawDataObjects

ByteStreamConversionSvc

MergedHits

L1Digits

L2Result

EFResult

L1 Emulation(inc. L1 ROD)

L1Result

ROD Emulation

(passthru)

L2 SelectionAlgorithm

EF SelectionAlgorithm

ByteStream

Use

s R

aw

Da

taO

bje

cts

ATLAS


Validation of Athena for HLT Use

The ATLAS EF will use selection and classification algorithms derived The ATLAS EF will use selection and classification algorithms derived

from the offline suitefrom the offline suite

Offline software performance therefore has a direct impact on EF farm Offline software performance therefore has a direct impact on EF farm

size and costsize and cost

The HLT community has started “validation studies” (detailed The HLT community has started “validation studies” (detailed

benchmarking) of Athena, offline algorithms, and event modelbenchmarking) of Athena, offline algorithms, and event model

The aim is to set metrics for monitoring trends in software performanceThe aim is to set metrics for monitoring trends in software performance

It is clear that the software is presently far from adequateIt is clear that the software is presently far from adequate Not fair to judge during development phase But benchmarking can (and has) helped spur improvements Feedback during monthly meetings with A-team and regular interactions with

developers

Software performance is also important for offline – hope that offline Software performance is also important for offline – hope that offline

community will continue this workcommunity will continue this work


Combined Reconstruction

egamma Reconstruction egamma Reconstruction Algorithms developed by H. Ma, S. Rajagopalan (BNL) Algorithms to associate clusters and tracks and analyze variables necessary

for e identification (shower shapes, isolation, E/p, …) Calorimeter Cluster calibration (J. McDonald, Pittsburgh)

Jet ReconstructionJet Reconstruction Jet Algorithms (KT and cone) developed by A. Gupta, F. Merritt (Chicago) Jet and Tau Calibration (F. Paige, H. Ma, S. Rajagopalan) (BNL)

H1 style calibration adopted : Provides weighting at a cell level. EM showers are denser than hadronic showers: Cells with dense energy

deposition are weighted toward EM scale. Effective in improving linearity and resolution over standard techniques

(sampling weights).

Missing ET ReconstructionMissing ET Reconstruction


Physics validation

DC1 data production includes datasets from single electrons, pions, DC1 data production includes datasets from single electrons, pions, di-jet events to full physics events with & without pile-up using G3.di-jet events to full physics events with & without pile-up using G3.

Much of this data is already being analyzed to extract the relevant

calibration constants that is fed back into the process for full

reconstruction. One of the physics signatures fully simulated is 50k SUSY events at One of the physics signatures fully simulated is 50k SUSY events at

the following msugra point : (I. Hinchliffe, F. Paige driving this effort)the following msugra point : (I. Hinchliffe, F. Paige driving this effort)

m0=100, m1/2=300, A0=-300, tan=6, sign() = +

Rich in leptons (including tau’s), jets, b-jets, high multiplicity hard events which is an ideal candidate to test the software.

Most such signatures have previously been studied only with fast simulation


e/Jet identification in SUSY events

First look at First look at 500 events from the SUSY sample : 500 events from the SUSY sample :


Summary

New ATLAS framework, Athena, enthusiastically embraced by broad spectrum New ATLAS framework, Athena, enthusiastically embraced by broad spectrum

of sub-system community.of sub-system community.

Many US physicists active in code developmentMany US physicists active in code development

Well integrated into overall ATLAS software effort

Schedule: Schedule:

DC 0 12/2001

First phase which provided a useful software continuity check

DC 1 02/2002

Large scale simulation/reconstruction with G3.

Phase 1 ongoing, Phase 2 due in March 2003.

Athens Physics Workshop (May 2003)

DC2 : Will use Geant4, Scheduled for early 2004

Documents

ATLAS Simulation/Reconstruction Software Reported by S. Rajagopalan work done by most US Institutes. U.S. ATLAS PCAP review Lawrence Berkeley National