(Università degli Studi di Milano-Bicocca, Italy)

Abstract: One of the most challenging tasks for urban excavation aimed at new archaeological findings is the preliminary inspection of the area with non-destructive in-situ techniques. State of the art technologies available for neutron-based methods, using cold, thermal and epithermal/fast neutron beams, are currently being applied to study CH artifacts at numerous neutron beam facilities throughout the world. The on-site Fast Neutron Logging System (FNLS) devised for deep analysis in urban areas, will provide elemental material characterization. The FNLS uses a fast (2.5 MeV)  neutron probe to realize a visual display of the hidden characteristics within the soil and hypothetical buried archaeological sites.
The portable neutron system will be based on a logging head that will be positioned in the soil as a mining probing method. The FNLS will be composed of  a fast neutron source and a germanium detector for the determination of gamma spectrum emitted by surrounding nuclei after absorption of neutrons moderated by the same surrounding soil. Prompt (during neutron pulses) and delayed (between adjacent neutron pulses) gamma emission arising from (neutron, gamma) interaction in the materials can give access to isotopic specific information. The visual display can provide a distribution of elements, determined by means of the induced radiation after neutron capture. Detection of abundant elements which are not usually contained in the soil of the particular site will provide a clue about a buried object. The same instrumentation will also be optimized to measure the natural radioactive background, detecting the naturally radioactive elements in the investigated archaeological area.
This will provide additional information on the elemental composition around the studied sites and detect interesting areas that worth to be excavated.

Keywords: neutron logging