MELBOURNE, FLA.—The Department of Homeland Security Domestic Nuclear Detection Office (DNDO) has approved second-year funding of $589,000 to Marcus Hohlmann, Florida Tech associate professor of physics and space sciences, to continue investigating the use of subatomic particles for detecting hidden nuclear materials in cargo. The funding extends the work Hohlmann began in 2007 with a DNDO investment. The project now totals $818,000.
The effort involves muon radiography. Muons are naturally produced by cosmic rays, which arrive from deep space and constantly bombard the Earth’s atmosphere. High-energy elementary particles, they are much heavier versions of electrons and are difficult to block by concrete or lead. Although muons are deeply penetrating, heavy nuclei that would be present in smuggled nuclear material could deflect them. The bigger the nuclei, the more the muons scatter.
Hohlmann is applying a novel type of micro-pattern particle detector, a gas electron multiplier (GEM). The GEM was initially developed at CERN, the European Laboratory for Particle Physics near Geneva, Switzerland.
“Our ultimate plan is to use the GEM detector for particle tracking to measure the deflection of muons so that cargo containers and vehicles crossing United States borders can be screened for nuclear contraband,” said Hohlmann.
Here is how the project works: Hohlmann and his team have demonstrated with computer simulations that the method can successfully distinguish nuclear material, such as uranium, from ordinary materials commonly found in cargo or vehicles. This includes steel, even if the uranium is deliberately shielded. They have also shown the GEMs can be more sensitive than other detector systems used for muon radiography.
In the next phase, they will develop detectors, electronics, and software for a data acquisition system and online data analysis. They’ll design, build and test the GEM prototype detector in a simulated cargo container. Associated signal readout electronics will provide information about the scattering angle of the muons as they pass in and out of the material. The wider the angle is, the bigger the nuclei inside and the greater the likelihood that the material is dangerous nuclear contraband.
“In addition to the need for technical development, the Department of Homeland Security believes there is a great need to train young people in this kind of technology,” said Hohlmann. “I agree that we must use our knowledge to check the evil consequences of nuclear technology. That’s what motivates me.”
Hohlmann is principal investigator (PI) on the grant and Debasis Mitra, Florida Tech associate professor of computer science, is co-PI. Also on the team are Kondo Gnanvo, post-doctoral researcher; Richard Hoch, master’s student; Amilkar Quintero Segovia, doctoral student; and undergraduates Patrick Ford, Jennifer Helsby and David Pena. Helsby recently received an award from the Florida Academy of Sciences for a presentation on this research.
For their simulations, the team is using about $74,000 of the grant to build—by students—Florida Tech’s most powerful high-performance computing cluster. The cluster, when complete, will be on a national computing grid.