There has been an increasing need to permit the quick, non-invasive, non-destructive analysis of the chemical compositions of materials, especially when such materials are concealed, such as illicit materials or explosives, or otherwise spaced a considerable distance from the detection system, such as to improve personnel safety in the event of an explosion. Thermal neutron activation analysis (TNAA) is a conventional method for determining chemical composition that utilizes neutrons to interrogate both samples in the laboratory and in concealed spaces. In TNAA, a source, generally of relatively low energy neutrons, is used to bombard the sample object of interest. Another possible method for using neutrons to interrogate different targets is neutron elastic scatter (NES). NES has the highest interaction probability of any of the interactions, as incident neutron interacts by scattering off the target nucleus in a perfect elastic scatter. As this is the most likely type of neutron interaction for most materials (especially lighter ones), a smaller incident neutron flux can be used, minimizing induced target radioactivity and potential danger to personnel.
Researcher at the University of Michigan developed a NES detector device for non-invasively detecting the presence of at least one predetermined element of interest. The detector device comprises a neutron source that simultaneously outputs, at a creation time, a neutron in one direction and an associated baseline particle in the opposite direction. The neutron can impinge upon the predetermined element and scatter therefrom in a third direction. A baseline particle detector system detects the baseline particle and outputs a baseline signal characteristic, and the processing unit analyzes the baseline signal and the scattering signal to determine the presence of the predetermined element.
Applications and Advantages
- Neutron detection
- Rapid, efficient, non-visual, reliable, sensitive, low rate of false-alarm.
- Minimized induced target radioactivity and potential danger to personnel.