WEOBB2
LBNL, Berkeley, California, USA
Associate particle imaging (API) is an active interrogation method for neutron based imaging of materials. Energetic alpha particles are emitted in kinematic correlation with neutrons in DT fusion reactions, forming a virtual neutron beam. When alphas are detected in a position sensitive detector and their arrival time is also recorded then time tagged neutrons can be used for 3D imaging e. g. of concealed objects in a transmission geometry or through detection of a prompt gamma ray. The imaging resolution in API systems is often limited by the area from which neutron originate. This area is determined by the spot size of a mixed D+ and T+ ion beam. We have adapted microwave driven ion sources (permanent magnets, 2.45 GHz) for the efficient production of hydrogen ions (all isotopes) with high current density (50 to 100 mA/cm2) and high fractions of atomic ions [1]. The high current density allows us to extract ions with small apertures and form beam spots on the neutron production target of less than 1 mm in diameter. In our presentation we will describe the API principle and report our results on the development of an API system with high spatial resolution.
[1] Q. Ji, AIP Conf. Proc. Vol 1336, 528-532 (2011).
