First neutron characterisation of ESS instruments: Acceptance tests for detectors and preparation for commissioning and user operation

Abstract ESS, a European Research Infrastructure Consortium (ERIC), is getting ready to be a leading multidisciplinary facility with the world’s most potent neutron source. Dedicated to scientific breakthroughs, ESS focuses on materials, energy, health, and environmental research to address key societal challenges. ESS will host 22 specialized scientific instruments selected to cover a broad range of experimental techniques and scientific disciplines. Among the instruments delivered by the In-Kind partners, DREAM, a versatile neutron powder diffractometer; LoKI, a small-angle neutron scattering instrument; and BIFROST, an extreme environment spectrometer, are expected to enter cold commissioning in Q4 2024. The detectors for these beamlines were already shipped to ESS, and are now undergoing the last performance and calibration tests before installation in their final positions. This paper presents the results of these tests, along with real-time updates on the progress of the host instruments.