Merging of imaging techniques based on reflectance hyperspectral and neutron tomography for characterization of modern replicas of a 13thcentury knife from Croatia

摘要

A large amount of iron and steel artifacts produced in the central European area between 2nd and 14th Centuries isconstituted by pattern welded iron-phosphoric iron and steel components. Phosphoric iron is a substitutional alloy, whichis obtained by using iron ore from swamps in which decomposition of dead organisms enriches the iron rich soil withphosphorous. The identification of phosphoric iron alloy in ancient artifacts is important for determining their place oforigin, production procedure and technological characteristics.A well-established technique for investigating the bulk structure of ancient metallographic artifacts is neutron tomography,using cold neutrons. It provides image-data capable of enhancing differences between phosphorous rich iron and thestandard iron areas. However, neutron imaging is costly and complex to implement. Therefore, the exploration of newtechniques capable of providing additional data on the nature of alloys would be highly needed. A pilot study addressed totest the applicability of reflectance hyperspectral imaging to the investigation of ancient metallographic artifacts ispresented here. So far this technique has been used for diagnostics of polychrome surfaces, but it has never been appliedto investigation of metallic surfaces.Hyperspectral imaging in the VIS-NIR range (400-1700 nm) was applied on replicas of a historical object from thearchaeological site of Kobilic (Croatia). The same replicas were analyzed also using neutron tomography. Hyperspectraldata were elaborated to map the distribution of the different phases on the surface. The comparison of the hyperspectraldata with the neutron tomography data-images provided prominent similarities. These preliminary results encouragefurther investigations on merging these two imaging techniques for novel applications on archeo-metallurgy.