Geant4 for GLAST BFEM- Comparison with Distributions in BFEM Data –

T. Mizuno, H. Mizushima, S. Ogata, Y. Fukazawa (Hiroshima/SLAC)M. Roterman, P. Valtersson (Royal Inst. of Tech/SLAC)

M. Ozaki (ISAS), T. Handa, B. Giebels, T. Kamae (SLAC)

(Note)• This work is in progress and hence the report is preliminary.

(Contents)• Hit distributions in BFEM• Two Cosmic Ray Models: with and without 0.6*sin(theta) term in albedo fluxes• Summary

1. CR Generator • Primary p, e-,

• Uniform angular distribution• Secondary p, e-, e+,+,-

• Angular distribution proportional to 1+ 0.6*sin(theta) • Uniform angular distribution (Steve Ritz’s choice)

• Secondary • Angular distribution adjusted to Schoenfelder et al.

2. Physics Simulation (The fixes not implemented yet)3. Digitization (w/charge sharing, w/o noise)4. Conversion to IRF File5. ROOTWriter (Thanks to Heather)

• Analysis (Presented here)• Reconstruction (Yet to be done)

Geant4 Simulation for BFEM – A Chart

Magnetic Rigidity etc for Palestine TX

Downward Proton Flux for Palestine TX

Downward Electron Flux for Palestine TX

Downward and Upward Electron Fluxes

Upward Electron Flux for Palestine TX

Angular Distributions for Electrons

Upward Gamma Ray Flux

Angular Distribution for Gamma Rays

Total G4 L1T: 517 Hz. (Real data: ~500 Hz) contribution proton: 219 Hz e-: 77.9 Hz e+: 46.2 Hz gamma: 89.0 Hz mu-: 32.8 Hz mu+: 52.7 Hz

Neutral: 54.8 Hz. (real data: ~50 Hz) contribution proton: 5.14 Hz e-: 8.09 Hz e+: 4.68 Hz gamma: 34.4 Hz mu-: 1.09 Hz mu+: 1.42 Hz

BFEM L1T Rate (G4 vs Real) for the Level Flight Sharper earth rim with sin(theta) albedo component

Hits in each layer (G4 vs Real) for “charged” particlesSharper earth rim with sin(theta) albedo component

G4

Data

Hits in each layer (G4) for all “charged” particle species Sharper earth rim with sin(theta) albedo component

Tot no. of layers hit (G4 vs Real) for “charged” particlesSharper earth rim with sin(theta) albedo component

G4

Data

Top-most layer hit (G4 vs Real) for “charged” particlesSharper earth rim with sin(theta) albedo component

G4Data

G4

Data

Hits in each layer (G4 vs Real) for “neutral” particlesSharper earth rim with sin(theta) albedo component

Hits in each layer (G4) for all “neutral” particle speciesSharper earth rim with sin(theta) albedo component

Tot no. of layers hit (G4 vs Real) for “neutral” particlesSharper earth rim with sin(theta) albedo component

G4

Data

Top-most layer hit (G4 vs Real) for “neutral” particlesSharper earth rim with sin(theta) albedo component

G4Data

We primarily want to find protons and muons. As these particles normally have straight tracks we can apply the following cuts: •Chi square of < 0.01•Hit in ACD panels•Single tracks only•Number of hits in tracker layers As we have missing silicon in top part of tracker we only look at bottom 16 layers.The above cuts does not include interactions as they produce several recon tracks.

Study on CR protons and muons Sharper earth rim with sin(theta) albedo component

Study on CR protons and muons: Top ACD and 8 layersSharper earth rim with sin(theta) albedo component

MC Protons = RedMC Muons (- & +) = YellowBFEM data = blue

MC Protons = RedMC Muons (- & +) = YellowBFEM data = blue

Study on CR protons and muons: All ACD and 8 layersSharper earth rim with sin(theta) albedo component

MC Protons = RedMC Muons (- & +) = YellowBFEM data = blue

Study on CR protons and muons: All ACD and 4 layersSharper earth rim with sin(theta) albedo component

Study on CR protons and muons: All side ACD and 4 layersSharper earth rim with sin(theta) albedo component

MC Protons = RedMC Muons (- & +) = YellowBFEM data = blue

BFEM L1T Rate (G4 vs Real) for the Level Flight Sharper earth rim without sin(theta) albedo component

Neutral: 50.1 Hz. (real data: ~50 Hz) contribution proton: 4.55 Hz e-: 5.24 Hz e+: 3.46 Hz gamma: 34.4 Hz mu-: 0.609 Hz mu+: 1.85 Hz

Total L1T: 448 Hz. (real data: ~500 Hz) contribution proton: 210 Hz e-: 53.7 Hz e+: 32.2 Hz gamma: 89.0 Hz mu-: 22.7 Hz mu+: 40.7 Hz

Hits in each layer (G4 vs Real) for “charged” particlesSharper earth rim without sin(theta) albedo component

G4

Data

Hits in each layer (G4) for all “charged” particle speciesSharper earth rim without sin(theta) albedo component

Tot no. of layers hit (G4 vs Real) for “charged” particlesSharper earth rim without sin(theta) albedo component

G4

Data

Top-most layer hit (G4 vs Real) for “charged” particlesSharper earth rim without sin(theta) albedo component

G4Data

G4

Data

Hits in each layer (G4 vs Real) for “neutral” particlesSharper earth rim without sin(theta) albedo component

Hits in each layer (G4) for all “neutral” particle speciesSharper earth rim without sin(theta) albedo component

Tot no. of layers hit (G4 vs Real) for “neutral” particlesSharper earth rim without sin(theta) albedo component

G4

Data

Top-most layer hit (G4 vs Real) for “neutral” particlesSharper earth rim without sin(theta) albedo component

G4

Data

Conclusion: Geant4 for BFEM- Comparison with Distributions in BFEM Data –

(Note)• This work is in progress and hence the report is preliminary.

(Conclusion)• Hit distributions are a powerful way to study the CR composition and angular dist

ribution.• More soft electrons/positrons(E< 20MeV?) to fill the lower portion of the Tracker.• Sharpness of the Earth Rim (as a source of soft gamma rays): BFEM may give a us

eful measurement! • Strength of the sin(theta) component: BFEM may give a constraint!.