Plasma accelerator for detection of hidden objects by using Nanosecond Impulse Neutron Inspection System (NINIS)

Nanosecond Neutron Analysis method and Fast Neutron Scattering Analysis technique, which recently have been developed within the program of hidden objects interrogation by fast neutrons, noticeably improve the problem of signal-to-noise ratio in comparison with previous practice. However they leave difficulties connected with a high necessary fluence and relatively long investigation time to be practically unresolved. The reason for it is too low brightness of neutron sources used (isotopes or classical diode-like accelerators). We propose to bring into play a neutron source based on a plasma accelerator, which generates very powerful pulses of neutrons in the nanosecond (ns) range of its duration. New generation of powerful neutron sources of the Dense Plasma Focus type can generate neutron pulses not only short by its duration (in the nano-second range), but provides a very high neutron yield in these pulses. Our device PF-6, recently put into operation at the Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland, has energy in its capacitor storage 7.4 kJ. Operated with the DPF chamber of a special design it is reckoned on a current maximum of the order of 800 kA with a quarter period of the discharge equal to 1 microsecond. It should generate in one pulse of ≅ 10-ns duration up to circa 109 D-D (2.5-MeV) neutrons or 1011 DT (14-MeV) neutrons. This feature gives a principal possibility to create a 'single-shot detection system'. It means that all necessary information will be received during a single very bright pulse of neutrons having duration in a nanosecond range by means of the time-of-flight technique with a short flight base. It might be a foundation for the creation of the Nanosecond Impulse Neutron Inspection System (NINIS). Because of these characteristics of the neutron source the signal-to-noise ratio will be increased just proportionally to the decreased number of shots (one instead of billions) whereas neutron fluence necessary to characterize hidden objects will be noticeably decreased. Due to these features this technique can be used in inspection of potential suicide bombers. An interrogation time in this case will now depend only on the data-processing system. In our report we present characteristics of the device as well as first results on its tests for the goals of NINIS method. (author)