Lyle G. Roybal

Detection and classification of concealed weapons using a magnetometer-based portal

A concealed weapons detection technology was developed through the support of the National Institute of Justice (NIJ) to provide a non intrusive means for rapid detection, location, and archiving of data (including visual) of potential suspects and weapon threats. This technology, developed by the Idaho National Engineering and Environmental Laboratory (INEEL), has been applied in a portal style weapons detection system using passive magnetic sensors as its basis. This paper will report on enhancements to the weapon detection system to enable weapon classification and to discriminate threats from non-threats. Advanced signal processing algorithms were used to analyze the magnetic spectrum generated when a person passes through a portal. These algorithms analyzed multiple variables including variance in the magnetic signature from random weapon placement and/or orientation. They perform pattern recognition and calculate the probability that the collected magnetic signature correlates to a known database of weapon versus non-weapon responses. Neural networks were used to further discriminate weapon type and identify controlled electronic items such as cell phones and pagers. False alarms were further reduced by analyzing the magnetic detector response by using a Joint Time Frequency Analysis digital signal processing technique. The frequency components and power spectrum for a given sensor response were derived. This unique fingerprint provided additional information to aid in signal analysis. This technology has the potential to produce major improvements in weapon detection and classification.

In situ characterization of crystal growth and heat treatment in semiconductor materials

In situ characterization methods are being developed at the Idaho National Laboratory that can be used to characterize the atomic lattice structure of materials used for semiconductor and scintillation detectors during the crystal growth and heat treatment processes, which have been shown to be critical for the development of optimized semiconductor and scintillation radiation detectors. Multiple methods for implanting positrons into the material have been developed and integrated with measurement techniques including Doppler broadening, coincidence Doppler broadening and positron lifetime measurement. The INL developed induced positron technique allows positron measurements to be performed at depth up to 10 cm inside crystal boules. Also, a portable measurement system suitable for field use has been developed that is suitable for assessing heat treatments at depths up to 1 cm inside a material in an industrial environment. Results of measurements that address the effects of composition and heatup/melting/cool down on material lattice structures are discussed along with plans for the in situ crystal studies.