Sci Fi Simulation Sci Fi Simulation StatusStatus

Malcolm EllisMalcolm Ellis

MICE MeetingMICE Meeting

Osaka, 2Osaka, 2ndnd August August 20042004

22

OutlineOutline

Status at last Status at last collaboration meetingcollaboration meeting

Progress since April:Progress since April:– dE/dx in track fitdE/dx in track fit– addition of fibres as addition of fibres as

measurementsmeasurements– pattern recognitionpattern recognition– current performancecurrent performance

momentum resolutionmomentum resolution efficiency/purityefficiency/purity

To-do/priority settingTo-do/priority setting

33

Status at CERN Status at CERN MeetingMeeting Prototype data had been analysed, Prototype data had been analysed,

light yield, efficiency, dead channels light yield, efficiency, dead channels and resolution matched expectations.and resolution matched expectations.

Specifications for next station used in Specifications for next station used in G4MICE, light yield, dead channels, etc G4MICE, light yield, dead channels, etc matched in G4MICE to prototype.matched in G4MICE to prototype.

Lack of time had meant some Lack of time had meant some improvements predicted at Abingdon improvements predicted at Abingdon meeting had yet to be implemented...meeting had yet to be implemented...

44

Beam/BackgroundsBeam/Backgrounds

All plots presented in this talk were All plots presented in this talk were produced with the following conditions:produced with the following conditions:– Beam: Default G4MICE beamBeam: Default G4MICE beam– RF Background: 0, 0.1, 1 and 10 times RF Background: 0, 0.1, 1 and 10 times

expected rate (100 impossible due to file expected rate (100 impossible due to file size)size)

– Detector description: current design, as Detector description: current design, as reported at CERNreported at CERN

– Only modification in datacards was to vary Only modification in datacards was to vary the RF background rate (see next slide)the RF background rate (see next slide)

Hope to start using beam from Hope to start using beam from G4Beamline once I have time to work G4Beamline once I have time to work with Kenny on this (not before with Kenny on this (not before September).September).

55

Sample datacardsSample datacards

numEvts 50000numEvts 50000 SciFiadcFactor 6.0SciFiadcFactor 6.0 SciFiFiberConvFactor 3284.0SciFiFiberConvFactor 3284.0 SciFivlpcEnergyRes 2.0SciFivlpcEnergyRes 2.0 SciFiMUXNum 7SciFiMUXNum 7 TPGMode OffTPGMode Off SciFiDeadChanFName SciFiDeadChanFName

nom.dclnom.dcl rfBGSource gammarfBGSource gamma rfBGPhotonModel UniformrfBGPhotonModel Uniform rfBGNumberOfPhotons 10rfBGNumberOfPhotons 10 rfBGDirection 1rfBGDirection 1 rfBGPhotonEnergy 10rfBGPhotonEnergy 10 rfBGTimeWindow 100rfBGTimeWindow 100 rfBGTimeDelay -15rfBGTimeDelay -15 rfBGZstart -5650rfBGZstart -5650 rfBGRadius 150rfBGRadius 150

Due to file size limitation (max 2G) didnot achieve 50k events for large background rates.

0.25% Dead channels as before

Same RF background model as beforeModify RF Background rate

66

Progress since AprilProgress since April

Improved model of dE/dx in the energy range Improved model of dE/dx in the energy range of interest has been added to the of interest has been added to the Reconstruction for use by the Kalman Reconstruction for use by the Kalman packagepackage

Prototype code to add clusters as Prototype code to add clusters as measurements in the track fit. Can not be measurements in the track fit. Can not be used fully until after the design iterationused fully until after the design iteration

Pattern recognition improved to enhance Pattern recognition improved to enhance purity of muon track selectionpurity of muon track selection

Code still does not “talk” to PID detectors, Code still does not “talk” to PID detectors, this will not happen until design-iteration is this will not happen until design-iteration is carried forward...carried forward...

77

dE/dx in KalmandE/dx in Kalman

Kalman package can Kalman package can accept a table of accept a table of mean dE/dx as a mean dE/dx as a function of total function of total momentum.momentum.

Currently, does not Currently, does not differentiate differentiate between particle between particle types.types.

dE/dx versus P dE/dx versus P determined from determined from GEANT4 and fed into GEANT4 and fed into Kalman for use in Kalman for use in ReconstructionReconstruction

88

Clusters in Track FitClusters in Track Fit

A space point (triplet) consists of three A space point (triplet) consists of three clusters, each describing a line in a clusters, each describing a line in a Sci-Fi plane.Sci-Fi plane.

These clusters can be added to the These clusters can be added to the track and used in the fit as individual track and used in the fit as individual measurements, rather than as the 3D measurements, rather than as the 3D space point of the intersection.space point of the intersection.

This allows efficiency to be recovered This allows efficiency to be recovered by adding 2 or even only 1 cluster per by adding 2 or even only 1 cluster per station to the track fit (next version).station to the track fit (next version).

99

Pattern RecognitionPattern Recognition

Proceeds as before, only changes Proceeds as before, only changes are extra cuts to remove are extra cuts to remove background and reduce CPU use.background and reduce CPU use.– Find clustersFind clusters– Build space points (only triplets)Build space points (only triplets)– Find straight tracks and lock off Find straight tracks and lock off

pointspoints– Find best helixFind best helix– Fit helixFit helix

1010

Space Points (Triplets)Space Points (Triplets)

A triplet should be three clusters A triplet should be three clusters (one in each view) which intersect (one in each view) which intersect in space and timein space and time

Pattern recognition checks the Pattern recognition checks the geometrical alignment of the geometrical alignment of the three fibres, as well as the three fibres, as well as the difference in time between them difference in time between them as recorded in the TDCsas recorded in the TDCs

1111

Triplet FindingTriplet Finding

1212

Straight TracksStraight Tracks

PPTT distribution shows a lot distribution shows a lot of RF induced background of RF induced background are essentially straight are essentially straight trackstracks

Use this to select potential Use this to select potential straight tracks and lock the straight tracks and lock the points off so that they will points off so that they will not be considered when not be considered when searching for a helixsearching for a helix

This produces a massive This produces a massive saving in CPU use for high saving in CPU use for high RF backgroundRF background

Potential for use of a better Potential for use of a better track model that does not track model that does not need to differentiate need to differentiate between “straight” and between “straight” and “curved” tracks – see Ken’s “curved” tracks – see Ken’s talk.talk.

1313

Straight TracksStraight Tracks

1414

Muon Track Muon Track RecognitionRecognition Pretty much as before:Pretty much as before:

– Pick three pointsPick three points– Determine the circle Determine the circle

parametersparameters– Check TDC information Check TDC information

is consistentis consistent– Look for a 4Look for a 4thth or 5 or 5thth

matching pointmatching point– Fit track using Kalman Fit track using Kalman

filterfilter– Pick track with best Pick track with best 22..

Use of the old MINUIT Use of the old MINUIT based code is gradually based code is gradually being phased out.being phased out.

By the time we move to By the time we move to the design iteration the design iteration version, it will not be version, it will not be used at all...used at all...

1515

Current PerformanceCurrent Performance

All plots following are with the expected All plots following are with the expected amount of RF background, 0.25% dead amount of RF background, 0.25% dead channels, conservative light yield, etc, etc...channels, conservative light yield, etc, etc...

Result purely Sci Fi, no matching to particle Result purely Sci Fi, no matching to particle ID detectors for PR or Particle ID (require ID detectors for PR or Particle ID (require design-iteration code for that)design-iteration code for that)

Position resolution effectively unchanged Position resolution effectively unchanged (slight variation due to new fibre spacing): (slight variation due to new fibre spacing):

~400 ~400 mm RMS values quoted versus RF level at end...RMS values quoted versus RF level at end...

1616

PPX X Resolution – 6.0%Resolution – 6.0%

1717

PPYY Resolution – 6.7% Resolution – 6.7%

1818

PPZZ Resolution – 1.9% Resolution – 1.9%

1919

PPTT Resolution – 4.7% Resolution – 4.7%

2020

X’ Resolution – 7.4%X’ Resolution – 7.4%

2121

Y’ Resolution – 7.8%Y’ Resolution – 7.8%

2222

T’ Resolution – 0.5%T’ Resolution – 0.5%

2323

Track-Finding Track-Finding EfficiencyEfficiency

2424

Track Purity – 99.8%Track Purity – 99.8%

2525

Variation with RFVariation with RF

RMS RMS ValuesValues

No RFNo RF 0.1 RF0.1 RF 1.0 RF1.0 RF 10.0 RF10.0 RF

StatisticsStatistics 5000050000 5000050000 2624726247 31833183

PPXX (MeV/c) (MeV/c) 1.681.68 1.681.68 1.751.75 1.861.86

PPYY (MeV/c) (MeV/c) 1.901.90 1.881.88 1.911.91 2.092.09

PPZZ (MeV/c) (MeV/c) 3.563.56 3.633.63 3.713.71 3.843.84

PPTT (MeV/c) (MeV/c) 1.681.68 1.681.68 1.751.75 1.651.65

X’ (mrad)X’ (mrad) 10.5310.53 10.6310.63 10.8510.85 7.797.79

Y’ (mrad)Y’ (mrad) 11.1211.12 11.1611.16 11.3611.36 11.3811.38

T’T’ 5.23E-35.23E-3 5.31E-35.31E-3 5.84E-35.84E-3 4.94E-34.94E-3

Purity InPurity In 99.8299.82 99.8199.81 99.8399.83 99.3399.33

Purity OutPurity Out 99.8399.83 99.8399.83 99.8299.82 99.3699.36

2626

Magnetic Field versus Magnetic Field versus P?P? Test the hypothesis that as the Test the hypothesis that as the

tracker is m/s limited, there is no tracker is m/s limited, there is no advantage to be had by lowering advantage to be had by lowering the solenoid field if the mean the solenoid field if the mean momentum is lowered.momentum is lowered.

Simulated 160 MeV/c muons at 4T Simulated 160 MeV/c muons at 4T and at 3.2T, compare momentum and at 3.2T, compare momentum resolution...resolution...

2727

160 MeV/c – 4T160 MeV/c – 4T

10.6 % 13.7 %

2828

160 MeV/c – 3.2T160 MeV/c – 3.2T

6.5 % 8.0 %

2929

To-do / Priority SettingTo-do / Priority Setting

Using a realistic description of tracker, Using a realistic description of tracker, background, etc, performance is better than background, etc, performance is better than 10% required.10% required.

Purity is very high.Purity is very high. Efficiency of PR requires more work.Efficiency of PR requires more work. Further major improvements will not be Further major improvements will not be

made without moving to the new design and made without moving to the new design and taking it forward.taking it forward.

Question – is the performance of this code (in Question – is the performance of this code (in CVS already) sufficient for other work (e.g. CVS already) sufficient for other work (e.g. emittance calculation) to carry on?emittance calculation) to carry on?

If so – as much effort as possible should be If so – as much effort as possible should be directed towards the new design.directed towards the new design.