Neutron activation analysis of meteorites at the VR-1 training reactor

Abstract

Samples of space objects were characterized using instrumental neutron activation analysis (NAA) combined with conversion electron Mössbauer spectrometry. Fragments of Moldavites, Muonionalusta meteorite and Sikhote-Alin meteorite were irradiated in the thermal neutron field of the low-power VR-1 training reactor operated by the Czech Technical University in Prague. Activated samples were investigated by means of nuclear gamma-spectrometry technique (semiconductor HPGe detector). Qualitative analysis revealed the occurrence of Na, Al, Mg, Cl, K, Ti, V, Mn, Fe, Sr, and Ba in Moldavites, Na, Cl, Mn, Fe, Co, Cu, Ni, As, and Au in Muonionalusta iron meteorite, and Ni, Co, Fe, and Mn in Sikhote-Alin iron meteorite. Employing the comparative NAA, the concentration of Na, Al, K, Ti, V, Fe, and Sr in Moldavite, concentration of Na, Fe, Ni, and Au in Muonionalusta meteorite, and concentration of Ni in Sikhote-Alin meteorite was determined. Moreover, Muonionalusta meteorite structure was investigated using the conversion electron Mössbauer spectrometry at room temperature, and α-(Fe, Ni) phase and γ-(Fe, Ni) phase were identified. The obtained results clearly show that the low-power VR-1 research reactor (80 W) is an excellent tool for NAA experiments, and that nuclear-analytical techniques can provide useful data for other scientific branches.