Neutron radiography as a NDT method in archaeology

Applications of NR in archaeology are indicated when searching for the presence of materials containg hydrogen like organic materials wood, fabrics, leather, or corrosion products and by metals, in particular heavy metal lead. In the recent,years the thermal neutron radiography (NR) has become a common non-destructive examination method at the National Museum of Slovenia, usefully complementing radiography by X- and gamma- rays and other NDT methods. The neutron irradiations are performed at the NR facility of the Ljubljana TRIGA Mark II research reactor at 250 kW power and using direct neutron imaging with thermoluminescent imaging plates (IP-ND's). Typical neutron fluences at the object plane are 10(6)-10(7) n/cm(2), collected during rather short exposure times of few to 30 seconds and thus keeping the activation level of the object below of the level set by the safety standard for public release. In the paper several recent applications of NR in archaeology will be described. Objects examined by NR range from artefacts salvaged from river bottoms, small statues, bronze and iron age and medieval weaponry, bronze boat shaped fibulae, roman treasure found and even neolithic ceramic objects. Due to the enlargement of European Union and falling borders and availability of NR sources at several research reactors through the EU it is important to make aware the community of archaeologists, conservationist and restorers about the opportunities of NR in their field of research and applications.