Tamás BELGYA1 / László SZENTMIKLÓSI1 / Zoltán KIS1 / Zsolt KASZTOVSZKY1 / Ralf SCHULZE2 / Petra KUDEJOVA2,3 / Thomas MATERNA4 / Lea CANELLA3 / Jan JOLIE2 and the ANCIENT CHARM Collaboration
(1Hungarian Academy of Sciences, Budapest, Hungary / 2University of Cologne, Germany / 3Technische Universität München, Garching, Germany / 4Institut Laue-Langevin, France)
Outline: To obtain the spatial distribution of the elements one possibility is to scan the sample with the help of a collimated neutron beam while collimating the ?-detector: Prompt Gamma Activation Imaging.
Prompt Gamma Activation Analysis (PGAA) is a neutron-based tool for non-destructive bulk elemental analysis, where the measured concentrations represent the average composition of the irradiated part, in most cases of few cm3. To obtain the spatial distribution of the elements one possibility is to scan the sample with the help of a collimated neutron beam while collimating the ?-detector: this method is called Prompt Gamma Activation Imaging (PGAI). To avoid the complete scanning of the object, PGAI is combined with Neutron Radiography (NR) or Neutron Tomography (NT). NR/NT produces high-resolution 2D/3D images that characterize the geometrical structure and neutron attenuation features of the object. Then the elemental composition needs to be measured only at selected spots. This makes the technique, called radiography/tomography-driven PGAI much less time consuming. By registrating the PGAI and NT data one obtains a complete data set of morphological properties and elemental distribution of the sample.
We have constructed a PGAI-NR/NT setup at the Budapest Research Reactor and also at the Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II) research reactor, Garching, in the framework of the European ANCIENT CHARM collaboration.. Both setups consisted of a high-resolution neutron tomograph, a germanium gamma-spectrometer and a xyz?-moving table for the positioning of the samples.
A spatial resolution better than 3 mm has already been achieved. Element maps for complex test samples and replicas of genuine museum objects were obtained by scans driven by tomography or radiography.
Keywords: prompt gamma activation imaging, neutron, 3D element mapping, Ancient Charm, radiography/tomography