The development and characterisation of novel neutron-detector technologies for ESS requires access to neutrons. Whilst ESS aspires to be the world’s leading source of neutrons, until construction is complete, neutron test beams are unavailable in Lund. This crucial gap is filled by the Source Testing Facility (STF) located in the Micro Beam Hall of the Physics Department at Lund University. Operated by the SONNIG Group of the Division of Nuclear Physics at Lund University in collaboration with the Detector Group at ESS, the STF is a fully functioning user facility. It boasts a complete range of gamma-ray and Be-based neutron sources for characterizations of detectors and is equipped with a the wide range of tools, electronics components, IT and detector-associated infrastructure essential to a hands-on user-focused laboratory. As there are no reactors or accelerators involved, the STF is an ideal, round-the-clock available locale for prototype development and commissioning.
The facility also offers a unique infrastructure: the Aquarium, a purpose-built experimental setup designed for "tagging" fast neutrons. Using this nuclear-physics based technique, the energy of a neutron is determined via time-of-flight on an event-by-event basis, allowing for the characterization of a detector response as function of neutron energy. Present efforts are focused upon constructing the infrastructure necessary for measuring absolute detection efficiencies. Thus, the STF is presently capable of measuring the fast-neutron backgrounds capabilities of detector prototypes for any of the ESS instruments. Future plans for the STF of relevance to detector development for ESS include the further development of the Aquarium to allow for the tagging of thermal neutrons via active moderators and state-of-the-art digitizing electronics.
The existing user group at the STF includes world-renowned experts in the field of neutron detection: the ESS Detector Group, the ESS Neutron Optics and Shielding Group, and the SONNIG group.