A small-angle neutron scattering instrument (SANS) has been delivered to the Argentine Neutron Beam Laboratory (LAHN – Laboratorio Argentino de Haces de Neutrones) at the Ezeiza Atomic Centre. Argentina’s National Atomic Energy Commission (CNEA – Comisión Nacional de Energía Atómica) said the SANS was donated by the German Helmholtz Zentrum Berlin (HZB) institute following the closure of the BER-II reactor in 2019. The instrument, which is 33 metres long when assembled, was delivered to the site in eight containers. The detection tube alone, which works in a high vacuum, is 16 metres long and 1.5 metres in diameter.

The SANS, previously called V4, is used to analyse structures in a size scale between 0.5 and 400 nanometres (nm). This enables investigation of materials, polymers, soft matter, electrochemicals, magnetic systems and biological samples, among others, at the nanoscale.

"The arrival of V4 is a key milestone for LAHN and is the result of a series of activities that began in 2015 building a close relationship of scientific-technological cooperation between Argentina and Germany through the CNEA and the HZB", noted LAHN Executive Director Karina Pierpauli.

When the BER-II reactor ceased operation, Argentina applied to house the V4 and to extend its operation using the neutron beams that the RA-10 multipurpose reactor will produce. The RA-10 is a 30 MWt open-pool research reactor for production of radioisotopes for medicinal and industrial use, with the capacity to meet a good part of the demand in Latin America. Will produce doped silicon, the highest quality raw material for the development of advanced electronic applications, and sources of industrial iridium for the evaluation of the integrity and quality of large-scale constructions. It will also enable research in basic sciences through the use of advanced neutron techniques, and in other fields such as pharmaceuticals, materials and biotechnology. The RA-10 will replace the RA-3 reactor, a 10 MWt pool-type reactor which began operations in 1967. The reactor is scheduled to be operating in 2025.

As part of the agreement between CNEA and HZB, Dr Paula Steinberg – who will be the scientist responsible for the operation and all the activities related to the instrument, visited Berlin in 2019, financed by the International Atomic Energy Agency (IAEA) to participate in the latest measurements made with this instrument before the final closure of the BER-II reactor. Also in 2019, CNEA engineers Federico Bertalot and Gabriel Santos Rueda travelled to Germany to familiarise themselves with the mechanical and control components of the instrument. In 2022, the head of the LAHN group of detectors, Dr Agustín Lucero, HZB to study the detection system.

Dr Daniel Clemens, who led the process of disassembly and packaging of the V4 at HZB, visited CNEA in 2022 and discussed with the LAHN team the technical details for technology transfer. The general agreement includes not only the transfer of equipment, but also a framework for scientific collaboration in the use of neutron beams on issues of energy transition and materials science, within which various cooperation activities are being carried out.

The instrument was disassembled between 2021 and 2022. Each piece was documented so that a LAHN team can reassemble it in the beam laboratory that is built next to the RA-10 multipurpose reactor at the Ezeiza Atomic Centre. The cold assembly will take place this year ready for when the RA-10 starts operating.

Due to the large dimensions of the SANS, the logistics of his transfer was a real challenge, CNEA said. After an extensive technical process and having managed to fulfil all the formalities required for its transportation from one nuclear centre to another, the instrument was packed into the eight containers that were shipped in the port of Hamburg for the journey to Buenos Aires. A ninth container, which requires special transportation for carrying irradiated components, will be arriving in February.

Image: An eight truck convoy delivers the giant German SANS to Argentina's Neutron Beam Laboratory (courtesy of CNEA)