This key milestone is the result of years of work. The ESS Bilbao Target Division led this relevant Spanish In-Kind contribution to the European Spallation Source ERIC in collaboration with our industrial partners AVS, Cadinox and Lloyds.

The vacuum test began last Thursday 21, ending yesterday Thursday 27. During these days measurements of dew point temperature, pressure rise and leak detection were performed, all of which were satisfactory. The final pressure obtained was 1*10-6 mbar with a leakage <1 * 10-8 mbar*l/s

The monolith vessel is one of the key elements of the target station that will confine all the activated material in case of accident and ensure the vacuum atmosphere around the target. For this reason, it is critical for ESS safety to ensure the highest quality standards during all the phases of the manufacturing process.

This complex component act as a pressure vessel enclosing the target wheel, the moderator, the reflector plugs as well as the central shielding block structures. It separates the interior void volume, including potential contamination therein, of the monolith from the ambient air atmosphere, both during normal operating condition and in off-normal situations. Specifically, the covers were designed to allow access of all monolith internals components in accordance with their expected lifetime and reliability.

The monolith also acts as structural support for components, plugs and shielding blocks. Therefore, an appropriate and repeatable alignment precision is needed especially for the target wheel unit and the moderator and reflector assemblies, relative the incident proton beam as well as the neutron beam extraction system.

The last step in the manufacturing process will be the final machining of the neutron port sections prior to the shipping and installation at the European Spallation Source ERIC in Lund, planned in early July.