Mobile imaging and spectroscopic threat identification (MISTI)

Characteristic gamma-radiation can be used to identify radiological threats, however gamma-ray detection and imaging is extremely difficult due to the low interaction probability and inability to focus high energy photons. MISTI’s hybrid system combines the exceptional spectroscopic capabilities of germanium with the cost effective collection power of a large volume sodium iodide imaging array. The system is a mobile, self contained, gamma-ray spectroscopy and imaging system for detecting radiological threats. While moving, the MISTI system is designed to detect sources of nuclear materials, such as a 1mCi Cs-137 source at distances up to 100m in 20s. The spectroscopic identification is performed using a 28 detector germanium array, which in turn triggers imaging using a 10x10 sodium iodide array, when a source is detected. The project is composed of commercial off the shelf technology, allowing a quicker transition from the design phase to the construction phase, reducing total cost. The data from the sensor will be analyzed in real time on board the vehicle and is combined with images and data from other instruments to provide users with a visual location of the source. MISTI’s unique design reduces false alarms, while improving weak source location and identification in urban and rural environments.