Field prototype of the ENEA neutron active interrogation device for the detection of dirty bombs

The Italian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA) Neutron Active Interrogation (NAI) device is a tool designed to improve CBRNE defense. It is designed to uncover radioactive and nuclear threats including those in the form of Improvised Explosive Devices (IEDs), the so-called “dirty bombs”. The NAI device, at its current development stage, allows to detect 6 g of 235U hidden in a package. It is easily transportable, light in weight, and with a real-time response. Its working principle is based on two stages: (1) an “active” stage in which neutrons are emitted by a neutron generator to interact with the item under inspection, and (2) a “passive” stage in which secondary neutrons are detected originating a signal that, once processed, allows recognition of the offence. In particular, a clear indication of the potential threat is obtained by a dedicated software based on the Differential Die-Away Time Analysis method.