MODELING TRAFFIC FLOW THROUGH MULTI-LANE PORTAL MONITORS USING THE FASTGAMMA SIMULATION SOFTWARE

We are developing a C++ software class library called FastGamma for modeling distributed detector networks in real time. FastGamma uses the multiple isotope material basis set (MIMBS) model to rapidly simulate attenuated gamma-ray spectra in a moving detector object from a collection of moving source objects located in a three-dimensional virtual landscape. It was designed to be called by a higher level controlling program to evaluate search strategies for locating threat sources in an urban environment and similar problems. However, it has many other potential uses. We have developed a simple calling program, named PortalSim, which uses the FastGamma library to model vehicle traffic patterns through multiple lane portal monitor systems, including non-barrier systems that allow vehicles to move through without stopping. In this presentation we demonstrate a modeling approach for determining the effect of various shielding options, including detector collimation and shielding between traffic lanes. A simple dynamic traffic flow example is presented.