Demonstration of coded-aperture fast-neutron imaging based on Timepix detector

Localization of radioactive hot spots is an important issue for nuclear industry (decommissioning, waste management, radiation protection) as well as for Homeland Security applications (non-proliferation of special nuclear material and management of nuclear accidents) or for nuclear research (Gen IV and fusion reactors). Seeking out the fast-neutron emission is of great interest as an alternative to only-gamma imaging techniques. This work presents a highly compact (19 × 14 × 15 cm3, 2.2 kg) fast-neutron imager based on a MURA coded-aperture and a Timepix detector equipped with a specific converter layer. Neutron detection is obtained by adding a conversion layer of paraffin, sensitive to fast neutrons, on the Timepix detector. This semiconductor pixel detector is capable of identifying the charged particles (protons in our case) resulting from the neutron interactions. This paper describes the design and characterization of the main building blocks of our fast-neutron imager. First experimental demonstration of the prototype version will be also presented.