Hohlmann Research Group

Hohlmann Research Group

Muon Tomography With GEM Detectors

The basic principle (click on image to see animation)  

Muon tomography (MT) based on the masurement of multiple scattering of atmospheric cosmic ray muons traversing containers is a promising candidate for identifying threatening made of high-Z material such as uranium and certain special nuclear material might be successfully smuggled across international borders by shielding the emanating radiation to evade detection by the standard radiation portal monitors currently operating at borders and ports. Since position-sensitive detectors with high spatial resolution should be particularly suited for tracking muons in a MT application, we propose to use compact micro-pattern gas detectors, such as gas electron multipliers (GEMs), for muon tomography. We present a detailed GEANT4 simulation of a GEM-based MT station for various scenarios of threat material detection. Cosmic ray muon tracks crossing the material are reconstructed with a point-of-closest-approach algorithm to form 3-D tomographic images of the target material. We investigate acceptance, Z-discrimination capability, effects of placement of high-Z material and shielding materials inside the cargo, and detector resolution effects for such a MT station.

Simulations of FIT Cubic-Foot Muon Tomography Station (click images) :




Key: (From left to right)

  • Row 1:
    • Simulation of muons traversing Cubic Foot Muon Tomography Station.
    • MT Visualization of uranium blocks arranged in "FIT" shape with GEM detectors shows. Two-axes rotation.
    • Same scenario as on the left, but with horizontal rotation only.
  • Row 2:
    • Zoomed MT visualization of uranium blocks arranged in "FIT" shape without detectors.
    • MT visualization of small iron, lead, and tantalum objects in a row.
    • MT visualization of a simulated 3 cm cube of iron in our minumal MT station.
    • Muon Tomography of a 3 cm cube of iron with our minimal MT station (real data).
  • Row 3:
    • MT visualization of iron, tin, lead, tunsten, and uranium targets arranged as the 5 on a die.
    • MT visualization of a uranium target within a cylinderical brass shield.

Related Documents

Construction of Triple GEM Detectors at CERN, October 2009

Manual for the CERN Standard 10 cm x 10 cm GEM Detectors