2009 Florida Academy of Sciences atSaint Leo University, Saint Leo, Florida

Performance comparison of the triple gas electron multiplier (GEM) and the drift tube muon detectors

used for muon tomography.

J. Locke, K. Gnanvo, R. Hoch, M. Hohlmann, D. Mitra.

Florida Institute of TechnologyDepartment of Physics and Space Sciences

150 West University BoulevardMelbourne, Florida 32901

Muon Tomography

Drift Tube vs. Gas Electron Multiplier (GEM) Detectors

Objective

Compare the performances of

drift tube and GEM

detectors used for

muon tomography.

Computer Simulation Tools• Geant4

– C++ based utility developed by the high energy physics community.

– Used to create geometry of scenarios and simulate particulate propagation through matter.

• CRY– Cosmic RaY muon production software. – Used to produce muons with momenta reflecting

observed natural momenta distributions .

• POCA– Point Of Closest Approach. – Used to calculate interaction points inside detectors,

where muons are likely to have scattered.

Scenario TestedBottom View Rear View

Targets (5) Engine

Detectors Targets (5)EngineBattery

Battery

Scenario exposed to cosmic ray muons for 10 minutes.

Performance: Resolution

Drift Tubes

GEMs

Mean Scattering

Angle (degrees)

(mm)x(mm)y

(mm)z

Performance: Distinguishing

Materials

U

Pb

Fe

Al W

Mean Scattering Angle(degrees)

Voxel

Drift Tubes

GEMs

U

Pb

Fe

Al W

Performance: Muon

Coverage

Muons / Voxel

Max. Muon / Voxel

Drift Tubes

GEMs

Conclusion

• GEM detectors are capable of higher resolution 3D reconstruction of scenarios than comparable drift tube detectors.

• GEM detectors are better capable of distinguishing between materials of similar densities than comparable drift tube detectors.

• GEM detectors are capable of higher coverage of muon activity within detector systems than comparable drift tube detectors.

Future Objectives for Muon Tomography at Florida Tech

• Simulate different detector arrangements (i.e. a trapezoidal prism, instead of a box) to determine more efficient arrangements.

• Gather statistical data for scattering angles of different materials.

• Replace the POCA algorithm with EM or another more accurate reconstruction algorithm.

2009 Florida Academy of Sciences atSaint Leo University, Saint Leo, Florida

Performance comparison of the triple gas electron multiplier (GEM) and the drift tube muon detectors

used for muon tomography.

J. Locke, K. Gnanvo, R. Hoch, M. Hohlmann, D. Mitra.

Florida Institute of TechnologyDepartment of Physics and Space Sciences

150 West University BoulevardMelbourne, Florida 32901