ИСТИНА

One of the problems within the framework of Dark Matter search experiments is the creation of a neutron absorption system - VETO. One of the most effective known neutron absorbers is gadolinium nuclei. The VETO system requires the development of a constructionl material in which gadolinium or its compounds would be uniformly distributed in the volume of the polymer matrix with Gd- concentration ~ 1 wt%. and total content of radioactive impurities less than 1 mBq/kg. In terms of Gd compounds, the U and Th contents should not exceed 50 ppt. We found commercial gadolinium containing preparations with chemical purity of 4N-5N in which the content of radioactive components varied by 3 orders of magnitude. The procedure of reduction of U and Th content to 50 ppt level has been developed. Several polymer matrixes were used to incorporate Gd nuclei and to achieve the homogeneity distribution. The mechanical properties of hybrid materials within 77-300 K temperature range were studied. The research was financially supported by the Ministry of Science and High Education of Russian Federation by the project RFMEFI60419X0238