Manufacturing techniques studies of ceramics by neutron and γ-ray radiography

Abstract

Abstract. In this study, the aim was to evaluate capabilities and constraints of radiographic imagery using thermal neutrons and gamma-rays as tools to identify the type of technique employed in ceramics manufacturing especially that used in prehistoric Brazilian pottery from Acre state. For this purpose, radiographic images of test objects made with clay of this region using both techniques -palette and rollers -have been acquired with a system comprised of a source of gamma-rays or thermal neutrons and a corresponding X-ray or neutron-sensitive Imaging Plate as detector. For the neutrongraphy samples were exposed to a thermal neutron flux of order of 10 5 n.cm -2 .s -1 for 3 minutes at main port of Argonauta research reactor of the Instituto de Engenharia Nuclear -IEN/CNEN. The radiographic images using γ-rays from 165 Dy (95 keV) and 198 Au (412 keV) both produced at this reactor, have been acquired under an exposure time of a couple of hours. After acquisition, images have undergone a treatment to improve their quality through enhancement of their contrast, a procedure involving corrections of the beam divergence, sample shape and averaging of the attenuation map profile. Preliminary results show that difference between manufacturing techniques is better identified by radiography using low energy γ-rays from 165 Dy rather than neutrongraphy or γ-rays from 198 Au. Nevertheless, disregarding the kind of employed radiation, it should be stressed that feasibility to apply the technique is tightly tied to homogeneity of the clay itself and tempers due to their different attenuation.