20 september 2005fabrizio cei1 status and perspectives of meg software fabrizio cei infn &...

20 September 20020 September 20055

Fabrizio CeiFabrizio Cei 11

Status and Status and Perspectives Perspectives

of MEG Softwareof MEG Software

Fabrizio CeiFabrizio Cei

INFN INFN && University University ofof Pisa Pisa

INFN Scientific Committee IINFN Scientific Committee I

NapoliNapoli, 20 September 2005, 20 September 2005



OutlineOutline

MC status and perspectivesMC status and perspectives

Offline status, perspectives Offline status, perspectives and milestonesand milestones

First Estimate of CPU/data storage First Estimate of CPU/data storage needsneeds

Contributions: Contributions:

TokyoTokyo, , PisaPisa, , LecceLecce,, PSI PSI, , RomaRoma and and PaviaPavia groups. groups.



MC status & MC status & perspectivesperspectives

• MEGEVE - Event Generator;MEGEVE - Event Generator;• GEMGEM – The detector simulator:– The detector simulator:

– Liquid Xenon Calorimeter;Liquid Xenon Calorimeter;– Drift Chamber;Drift Chamber;– Timing Counter;Timing Counter;– Magnet and Target.Magnet and Target.

• ZEBRA Output and Analysis Tools;ZEBRA Output and Analysis Tools;• Event Cocktail: the MEG “Bartender”;Event Cocktail: the MEG “Bartender”;• LP/Beam Test fully simulated LP/Beam Test fully simulated (not discussed)(not discussed);;• MC code MC code almost ready for preproduction almost ready for preproduction

tests.tests.



Energy release in LXeEnergy release in LXe

Positron trackPositron track

Hits on TCHits on TC



MEGEVE: the event MEGEVE: the event generatorgenerator

• StatusStatus– Signal events;Signal events;– Michel positrons;Michel positrons;– Radiative decay (RD):Radiative decay (RD):

• Exact formulae for unpolarized muon;Exact formulae for unpolarized muon;• Approximation for polarized muon (back-to-back, PApproximation for polarized muon (back-to-back, Pe e P P 52.8 52.8

MeV).MeV).– Positron annihilation in flight (AIF):Positron annihilation in flight (AIF):

• Preliminary AIF within target;Preliminary AIF within target;• Started study for realistic AIF: magnet, DCH, TC and Target.Started study for realistic AIF: magnet, DCH, TC and Target.

– Scheme to generate pile-up events: (Michel + RD, Michel + AIF, AIF Scheme to generate pile-up events: (Michel + RD, Michel + AIF, AIF + RD, + RD,

RD + RD) + additional Michel decays; more than two events can be RD + RD) + additional Michel decays; more than two events can be overlaid;overlaid;

- CPU time: 2 CPU time: 2 6 sec/event, dominated by scintillation photon 6 sec/event, dominated by scintillation photon tracking tracking

(maybe it can be improved).(maybe it can be improved).• NextNext

– Exact formulae for polarized muon’s radiative decay;Exact formulae for polarized muon’s radiative decay;– Realistic AIF and background studies (under way);Realistic AIF and background studies (under way);– Study of online/offline pre-selection and calibrations (under way).Study of online/offline pre-selection and calibrations (under way).



Background studies under way Background studies under way 1)1)

Accidental background from Accidental background from superimposition superimposition of a Michel positron and a of a Michel positron and a from radiative from radiative decaydecay. .

Simulation of Simulation of trigger trigger conditionsconditions quoted in the quoted in the Proposal Proposal

– Photon energy cut Photon energy cut EE > 45 > 45 MeVMeV

– Time window eTime window e++ - - △T = 10 △T = 10 nsns

– ee++- - direction matching direction matchingPreliminary WorkPreliminary WorkE (MeV)E (MeV)



Background studies under way Background studies under way 2)2)

Realistic studies of Michel positron annihilation in Realistic studies of Michel positron annihilation in flight. flight. Almost complete detector simulationAlmost complete detector simulation (not the target (not the target only).only).Main contributionsMain contributions from from targettarget and and drift chambersdrift chambers..

Annihilation Annihilation energy spectrum in LXe energy spectrum in LXe

Preliminary WorkPreliminary Work



Detector simulation 1) Detector simulation 1) LXeLXe

• StatusStatus– Geometry: revised shape for vacuum vessel, PMT holders and Geometry: revised shape for vacuum vessel, PMT holders and

honeycomb;honeycomb;– Implemented decay curve and wavelength spectrum of LXe Implemented decay curve and wavelength spectrum of LXe

scintillation;scintillation;– GEANT based scintillation photon tracking:GEANT based scintillation photon tracking:

• Reflection on PMT quartz window and PMT holders;Reflection on PMT quartz window and PMT holders;• PMT quartz window transmittance;PMT quartz window transmittance;• Absorption and scattering in Liquid Xenon.Absorption and scattering in Liquid Xenon.

– Outputs:Outputs:• Energy deposit, position and timing in Liquid Xenon;Energy deposit, position and timing in Liquid Xenon;• Preliminary waveform output: hit timing of scintillation photonsPreliminary waveform output: hit timing of scintillation photons for each PMT (for each PMT ( ～～ 3 x 103 x 104 4 photoelectrons photoelectrons @ 50 MeV).@ 50 MeV).

• NextNext– Update geometry to match the final design (almost done);Update geometry to match the final design (almost done);– Implement support structure;Implement support structure;– ““Fast” scintillation photon tracking; multiple options ? (GNEXT/hand Fast” scintillation photon tracking; multiple options ? (GNEXT/hand

made).made).



Detector simulation 2) Detector simulation 2) DCHDCH

• StatusStatus– Geometry:Geometry:

• DCH geometry completed; wires simulated; DCH geometry completed; wires simulated; Helium bag included, but turned off by default;Helium bag included, but turned off by default;• Implementation of the Vernier pad.Implementation of the Vernier pad.

– Isochrones tables for various B-field;Isochrones tables for various B-field;– Outputs:Outputs:

• Entrance/Exit position from cells;Entrance/Exit position from cells;• Energy, timing and direction for each hit;Energy, timing and direction for each hit;• Drift time in cells.Drift time in cells.

• NextNext - Update geometry for latest DCH support and peripherals;- Update geometry for latest DCH support and peripherals; - Implement charge and time signal simulation on wires & pads; - Implement charge and time signal simulation on wires & pads; - Implement waveform digitization.- Implement waveform digitization.



Detector simulation 3) Detector simulation 3) TCTC

• StatusStatus– Geometry: scintillation bars/fibers, PMTs, APDs and light guides.Geometry: scintillation bars/fibers, PMTs, APDs and light guides.– Outputs:Outputs:

• Hit position, timing and energy;Hit position, timing and energy;• Energy release and step length for each GEANT hit; Energy release and step length for each GEANT hit; • Waveform outputs for scintillation bars.Waveform outputs for scintillation bars.

– Photon propagation inside the curved fibers recently Photon propagation inside the curved fibers recently implemented.implemented.

• NextNext– Implement support structure;Implement support structure;– Waveform for scintillation fibers;Waveform for scintillation fibers;

- A standalone MC for comparison with scintillation bar beam test.- A standalone MC for comparison with scintillation bar beam test.



Detector simulation 4) Detector simulation 4) Target and MagnetTarget and Magnet

• StatusStatus

- Preliminary approach outside GEM;- Preliminary approach outside GEM;

- Realistic treatment of target geometry included in GEM.- Realistic treatment of target geometry included in GEM.• NextNext

– Implement target support;Implement target support;– Beam transport within the detector;Beam transport within the detector;– Create and implement the module “beam” within GEM.Create and implement the module “beam” within GEM.



ZEBRA Output & Analysis ZEBRA Output & Analysis ToolsTools

• HitsHits– Energy deposit, position and timing for LXe/DCH/TC;Energy deposit, position and timing for LXe/DCH/TC;– Scintillation photon hits for LXe and TC PMTs.Scintillation photon hits for LXe and TC PMTs.

• Preliminary waveform outputPreliminary waveform output

- Brute force approach: record - Brute force approach: record all hit timing for each PMT all hit timing for each PMT (LXe)(LXe)

3 x 103 x 1044 photons @ 500 PMTs/828 PMTs for 52.8 MeV gamma photons @ 500 PMTs/828 PMTs for 52.8 MeV gamma

⇒ ⇒ 120 kB/event (w/ zero suppression); few kB/event 120 kB/event (w/ zero suppression); few kB/event from TC;from TC;

- Need binned waveforms to save disk space.- Need binned waveforms to save disk space. • Analysis toolsAnalysis tools -- ZEBRA2NTUPLEZEBRA2NTUPLE - - ZEBRA2ROOTZEBRA2ROOT – based on – based on ROME frameworkROME framework; ; temporary software temporary software waiting for MegRootwaiting for MegRoot



The MEG “Bartender” 1)The MEG “Bartender” 1)• ROOT basedROOT based program for program for

Event CocktailEvent Cocktail;;

• Read Read experimentalexperimental and and simulation datasimulation data;;

• Make Make mixture mixture of severalof several MC sub eventsMC sub events;;

• Simulation of Simulation of pulse pulse shapeshape of MC data of MC data ((digitizationdigitization));;

• Rearrange Rearrange channels of channels of experimental dataexperimental data to to make them as MC.make them as MC.

• PossiblePossible simple simple calibrationcalibration;;

• PossiblePossible trigger trigger simulationsimulation..

(R. Sawada, (R. Sawada, S. Yamada)S. Yamada)



The MEG “Bartender” 2)The MEG “Bartender” 2)

+ =Nphe = 620Nphe = 620Nphe = 123Nphe = 123

Example: Example: waveform pile-upwaveform pile-up

three possible three possible models of single waveformmodels of single waveform;; gaussiangaussian, , sinusoidalsinusoidal or or constant noiseconstant noise can be added; can be added; event rateevent rate can be specified; can be specified; relative timingrelative timing is extracted randomly. is extracted randomly.



Offline status 1)Offline status 1)

MegRootMegRoot

Main framework, Main framework, based on ROOT;based on ROOT; Under development,Under development, mainly in Lecce.mainly in Lecce.

ROMEROME

Backup framework, Backup framework, also based on ROOT;also based on ROOT; Developed at PSI;Developed at PSI; Already used for beam Already used for beam test analysis.test analysis.



Offline status 2)Offline status 2)

MegRoot:MegRoot:- First version recently released;- First version recently released;

- - BackboneBackbone from from AliRootAliRoot;;

- Copyrights issues solved with F. Carminati;- Copyrights issues solved with F. Carminati;

- Included algorithms: - Included algorithms: Alice, GEM Alice, GEM oror proprietary proprietary..

- - 4 Modules, 344 Classes, > 4000 Methods4 Modules, 344 Classes, > 4000 Methods..

Other topics:Other topics: - - Promising pattern recognition and trackingPromising pattern recognition and tracking

algorithms algorithms under development.under development.



MegRoot ContributorsMegRoot Contributors

• Main ArchitectureMain Architecture: Alice collaboration, : Alice collaboration, V. Di V. Di BenedettoBenedetto

• MagnetMagnet: : E. CavalloE. Cavallo, W. Ootani, W. Ootani• DCHDCH: C. Chiri, : C. Chiri, F. IgnatovF. Ignatov, M. Schneebeli, S. , M. Schneebeli, S.

Spagnolo, Spagnolo,

G. TassielliG. Tassielli, H. Nishiguchi, H. Nishiguchi• LXeLXe: : V. Di BenedettoV. Di Benedetto, S. Mihara , R. Pazzi, R. , S. Mihara , R. Pazzi, R.

Sawada, Sawada,

G. Signorelli, G. Signorelli, G. TerraccianoG. Terracciano• TCTC: : G. SiragusaG. Siragusa• Event Generator for VMCEvent Generator for VMC: F. Cei, : F. Cei, A. MazzacaneA. Mazzacane• DatabaseDatabase: : D. BarbareschiD. Barbareschi, R. Sawada, R. Sawada

Blue: Blue: young people who recently joined the collaborationyoung people who recently joined the collaboration



MegRoot ArchitectureMegRoot Architecture

• MegRoot FrameworkMegRoot Framework– Based on Based on ROOTROOT– User code in User code in C++C++– Usage of Usage of FORTRAN librariesFORTRAN libraries

• Geant3, event generators, “microcernlib”Geant3, event generators, “microcernlib”

• Integrates reconstruction and analysis Integrates reconstruction and analysis softwaresoftware

• Each detector subsystem has one single Each detector subsystem has one single packagepackage (one (one

directory, one library); detector geometry is hard-directory, one library); detector geometry is hard-codedcoded

• Calibration constants read via Calibration constants read via MySQLMySQL interfaceinterface

(to be unified with MC)(to be unified with MC)..



MegRoot statusMegRoot status

• StructureStructure of of all Classesall Classes completecomplete up to the Digitization up to the Digitization stepstep

(main purpose is to (main purpose is to test the Reconstruction Modulestest the Reconstruction Modules););• All All MethodsMethods designed;designed; most algorithmsmost algorithms implemented;implemented;• The The Reconstruction ClassReconstruction Class is currently is currently being designed:being designed:

- DCH reconstruction & Kalman filter almost - DCH reconstruction & Kalman filter almost completed;completed;

- TC & LXe: under development.- TC & LXe: under development. • Reconstruction Class will read out Reconstruction Class will read out ROOT ObjectsROOT Objects ((MC DigitsMC Digits) or ) or streamer objectsstreamer objects ( (raw dataraw data););• Intense collaborationIntense collaboration between Detector Experts and between Detector Experts and Core Offline Group under way;Core Offline Group under way;• Lecce people are Lecce people are joining the effort to bring the LP code joining the effort to bring the LP code

withinwithin MegRoot and analyze the dataMegRoot and analyze the data with the rest of the with the rest of the

collaboration.collaboration.



What’s missing in What’s missing in MegRootMegRoot

• Waveform decoding: studies under Waveform decoding: studies under way.way.

• Detailed structure of the Detailed structure of the Reconstruction Reconstruction classclass

• MySQL interfaceMySQL interface needs to be extended to needs to be extended to the the finalfinal Detector Detector (presently it (presently it only works only works for LPfor LP))

• Calibration ModuleCalibration Module• Farm Manager CodeFarm Manager Code ( (Global/LocalGlobal/Local))• Not final geometry Not final geometry (to be borrowed from (to be borrowed from

GEM)GEM)

It could be one of the It could be one of the most CPU consuming most CPU consuming

processesprocesses



Offline MilestonesOffline Milestones

• LP in MegRoot: LP in MegRoot:

geometry & event display completed; geometry & event display completed;

data decoding: OK for MC, under way for data; data decoding: OK for MC, under way for data;

analysis within Octoberanalysis within October

• Code implementation in CVSCode implementation in CVS: : September September 20052005

• Reconstruction ClassReconstruction Class: : October 2005October 2005 • Estimate LXe analysis CPU loadEstimate LXe analysis CPU load: : October October

20052005• Calibration ModuleCalibration Module: it will start in : it will start in

November 2005November 2005 (after completion of (after completion of Reconstruction Class)Reconstruction Class)



Pattern Recognition Pattern Recognition StudiesStudies

First algorithm developed in PisaFirst algorithm developed in Pisa (2003): (2003): combined use of combined use of detector segmentationdetector segmentation, , fast momentum fast momentum reconstructionreconstruction and and geometrical correlationsgeometrical correlations between hits between hits in a track; in a track; New algorithm developed in LecceNew algorithm developed in Lecce (2005): (2005): - complete simulation of - complete simulation of time measurementtime measurement; ; - definition of - definition of signal sensitive parameterssignal sensitive parameters for for discriminatingdiscriminating tracks related to physical trigger from backgroundtracks related to physical trigger from background;; - - space point reconstructionspace point reconstruction by using timing information; by using timing information; - - technical note in progresstechnical note in progress.. Typical Typical backgroundbackground: : 5 Michel positron tracks5 Michel positron tracks for both for both algorithms.algorithms. Similar performances: Similar performances: 95 % efficiency in reconstructing 95 % efficiency in reconstructing goodgood trackstracks, with , with few per cent contaminationfew per cent contamination of spurious hits; of spurious hits; Complementary techniques; Complementary techniques; possible merging ?possible merging ? Timing counter information to be insertedTiming counter information to be inserted (possible (possible improvement improvement in discrimination power).in discrimination power).



Track fitting studiesTrack fitting studies

Kalman filter based algorithm under development; Kalman filter based algorithm under development; preliminary resultspreliminary results..

Reconstructed Reconstructed tracks (5 etracks (5 e++’s)’s)

Momentum reconstruction: Momentum reconstruction: p/p p/p 1.4 % 1.4 %

Resolutions:Resolutions: Target position AngleTarget position Angle RR ~ 1.7 mm ~ 1.7 mm = 8 mrad = 8 mrad zz ~ 1.9 mm ~ 1.9 mm = 6 mrad = 6 mrad



First estimate of First estimate of CPU/data storage needsCPU/data storage needs

• IngredientsIngredients - - MC productionMC production• GEANT3 simulationGEANT3 simulation• Hit production & digitizationHit production & digitization

- - Data/MC reconstructionData/MC reconstruction (partial) (partial)• Computations based on Computations based on Pentium IIIPentium III, , 1.4 GHz 1.4 GHz

for datafor data

(faster computers available), (faster computers available), Pentium IV, 3.0 GHz for Pentium IV, 3.0 GHz for MCMC

• Data reconstructionData reconstruction– LXeLXe: LP beam test data; QSUM, Linear Fit and MINUIT fit: LP beam test data; QSUM, Linear Fit and MINUIT fit– DCHDCH: Kalman Filter to 5 simulated charged tracks & : Kalman Filter to 5 simulated charged tracks & Track extrapolation to TC (1.2 x storage and 1.5 x Track extrapolation to TC (1.2 x storage and 1.5 x

CPU)CPU) - - TCTC: Not implemented: Not implemented

• Waveform decoding not implementedWaveform decoding not implemented



CPU estimates CPU estimates (msec/evt) 1)(msec/evt) 1)

Hits Hits ProductionProduction

DigitsDigits

ProductioProductionn

ReconstructionReconstruction

Montecarlo event Montecarlo event generation generation

2000 – 60002000 – 6000

Bartender (no Bartender (no noise)noise)

230 230

DCH reconstructionDCH reconstruction 200 200 (MC) (MC)

LXe reconstructionLXe reconstruction 40 – 80 40 – 80 (LP data)(LP data)

TC reconstructionTC reconstruction not includednot included

TotalTotal 2000 - 60002000 - 6000 230230 250 – 300250 – 300



CPU estimates 2)CPU estimates 2)• AssumptionsAssumptions::

– Trigger rate: Trigger rate: 20 Hz 20 Hz (physical events)(physical events)- - MC:MC:

- - 101012 12 accidental eventsaccidental events obtained by “Event Cocktail” obtained by “Event Cocktail” ((101066 Michel positrons & Michel positrons & 101066 AIF/RD photons)/year; AIF/RD photons)/year; Reconstruct ~ 10Reconstruct ~ 1088 events events & use others for occupancy & use others for occupancy

checks;checks;- - 2 x 102 x 1077 correlated eventscorrelated events in the signal region/year. in the signal region/year.

• Results:Results:

- - Montecarlo productionMontecarlo production & event cocktail: & event cocktail: 10 10 30 30 CPUCPU

- - MC/Raw data ReconstructionMC/Raw data Reconstruction: : 20 20 CPU/proc.CPU/proc.

- WF decoding not implemented; studies under way; - WF decoding not implemented; studies under way;

- Calibrations to be estimated;- Calibrations to be estimated;

- No pre-filtering - No pre-filtering (it could (it could reduce CPU timereduce CPU time))..



Data Storage Estimate Data Storage Estimate 1)1)

A) REAL DATAA) REAL DATA Assume 10Assume 107 7 sec/year & an overall trigger rate of 100 sec/year & an overall trigger rate of 100 Hz, Hz, 20 Hz20 Hz of of physical dataphysical data and and 80 Hz80 Hz of of calibrationscalibrations;; Waveform data (channel occupancy assumed: 50 % Waveform data (channel occupancy assumed: 50 % for for LXe, 10 % for DCH & TC): LXe, 10 % for DCH & TC): 1.2 Mb/event 1.2 Mb/event 120 120 Mb/secMb/sec;; Compression factorsCompression factors: : 10 for true events10 for true events (obtained in PIBETA); (obtained in PIBETA); 100 for calibrations100 for calibrations 0.12 Mb/event for 0.12 Mb/event for physical physical events, 0.012 Mb/event for calibrationsevents, 0.012 Mb/event for calibrations

Data storageData storage: (20 x 0.12 + 80 x 0.012) Mb/sec = : (20 x 0.12 + 80 x 0.012) Mb/sec = 3.4 3.4

Mb/secMb/sec

3.4 Mb/sec x 103.4 Mb/sec x 1077 sec/year = sec/year = 34 34

Tbyte/yearTbyte/year




B) MONTE CARLOB) MONTE CARLO Assume a total production of Assume a total production of 10101212 accidental events accidental events (dominant(dominant background in the signal window) and background in the signal window) and 2 x 102 x 1077 correlated correlated events/yearevents/year (first sample obtained by merging (first sample obtained by merging two 10two 1066 independent samplesindependent samples of positrons & photons). To reduce of positrons & photons). To reduce problems problems of multiple disk accesses, MC events must be duplicated of multiple disk accesses, MC events must be duplicated ((x 2 correlated, x 20 accidentalx 2 correlated, x 20 accidental). ). Event size based on LXe (photon arrival times) and TC Event size based on LXe (photon arrival times) and TC information: information: 200 kb/event200 kb/event; waveforms not simulated and noise not ; waveforms not simulated and noise not included. included. Data storageData storage: : - - (200 kb/event x 2 x 10(200 kb/event x 2 x 1077 x 2) = x 2) = 8 Tb/year8 Tb/year (correlated (correlated events);events);

- - (200 kb/event x 2 x 10(200 kb/event x 2 x 1066 x 20) = x 20) = 8 Tb/year8 Tb/year (uncorrelated (uncorrelated events); + events); + factor 3 for digitizationfactor 3 for digitization::

TOTAL ~ 50 Tb/yearTOTAL ~ 50 Tb/year




SummarySummary

Real data: Real data: 34 Tbytes/year34 Tbytes/yearMonte Carlo: Monte Carlo: ~ 50 Tbytes/year~ 50 Tbytes/yearOverhead Overhead (DSTs, reconstructed info …) (DSTs, reconstructed info …) ~ 15 ~ 15 Tbytes/yearTbytes/year____________________________________________________________________________________Total Total ~ 100 Tbytes/year~ 100 Tbytes/year



ConclusionsConclusions

Relevant progressesRelevant progresses were obtained in were obtained in MCMC and and offline frameworkoffline framework;; About About 10 young people joined the collaboration10 young people joined the collaboration in the in the

offline coreoffline core group; the group; the MC groupMC group is also in expansionis also in expansion; ; A A first version of Offline frameworkfirst version of Offline framework was released was released; ;

important milestonesimportant milestones were defined for the Offline group; were defined for the Offline group; Other software jobs are under wayOther software jobs are under way: : trackingtracking and and patternpattern

recognitionrecognition algorithms, studies of possible algorithms, studies of possible calibration procedurescalibration procedures … … Thanks to the Thanks to the experience gained in the beam testexperience gained in the beam test and to the and to the

good level of sophistication reached by the MC codegood level of sophistication reached by the MC code we are we are

in a position to in a position to perform a first estimateperform a first estimate of of CPU powerCPU power and and

disk storage needsdisk storage needs of our experiment. of our experiment. We are starting to We are starting to think at physics analysisthink at physics analysis ( (likelihood, blindlikelihood, blind …) …)



Backup slidesBackup slides



MegRoot structureMegRoot structure

MegRooMegRoott

run management interface classes detector base classes data structure base classes

Detectors DCH LXE

FMDTC

STEER

PYTHIA6

Geant3

MICROCERN

Geant4ROOT

HIJING …EVGEN

Geant3 VMCGeant4 VMCExternalExternalpackagepackage

ss

VMC



ROME featuresROME features

• ROME is a ROME is a framework generatorframework generator..

• Only Only 6 different objects6 different objects with with up to 6 access methodsup to 6 access methods..

• All All classes are generatedclasses are generated, only event methods have to be , only event methods have to be

written.written.

• No knowledge about object oriented programmingNo knowledge about object oriented programming is is

needed.needed.

• Folders and Tasks support a Folders and Tasks support a very clear program structurevery clear program structure..

• Modularity: Modularity: tasks can be exchanged even at runtimetasks can be exchanged even at runtime..

20 september 2005fabrizio cei1 status and perspectives of meg software fabrizio cei infn &...

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