PINS3 Technical Description

PINS3 Technical DescpritionPrinciple of Operation: The Physics

PINS is a novel application of a well-understood technique, involving the interrogation of a container, using neutrons from a small moderated source. The neutrons pass through the wall of the container and collide with the atomic nuclei of the contents.

The ensuing nuclear reactions ("neutron capture" and "inelastic scattering") produce gamma rays, which when appropriately detected and recorded, produce a gamma-ray spectrum. The gamma-ray spectrum peaks are found at channel numbers corresponding to energies associated with specific nuclear de-excitations characteristic of the chemical element concerned. The relative heights of the peaks are related to the ratios of the elements inside the container. These energies and ratios are in themselves UNIQUELY characteristic of the contents of the container, whether high explosive, nerve gas, or other. In this way, with a "library" of known signatures, it is possible to
determine unambiguously the contents of the container.

PINS3 Technical DescriptionThe extent to which the result is "certain" is illustrated by a real world example, in which a PINS system was used to confirm the contents of a compressed gas cylinder found buried in the ground.

It can be clearly seen that the spectrum from the container and the spectrum from a cylinder known to contain HF are an excellent match. This "fingerprinting" approach is the essence of the method.