Marianne Ekdahl

The European Spallation Source Neutrino Super Beam, ESSnuSB+, is a design study project within particle physics. Aiming at the construction of an international neutrino laboratory, the conceptual design builds on an extension and upgrade of the ESS proton accelerator from 5 MW to 10 MW, a target, near detectors at the ESS site and far detectors of a volume of around 1 million m3 down in the Zinkgruvan mine near Askersund. The project is supported by two Design Studies, ESSnuSB and ESSnuSB+, financed by the European Commission. It is composed of 20 participating research institutes from 11 countries. The project's science focus is the study of neutrinos to gain understanding of the matter-antimatter asymmetry in the universe - in other words, why matter exists. Recent measurements of neutrino oscillation indicate that the discovery of so called Charge-Parity Violation in neutrinos becomes an important candidate for explaining the dominance of matter over antimatter in the universe. However, the low interaction of neutrinos with matter make them difficult to detect, requiring very large detectors. The ESSnuSB+ project builds on two outstanding opportunities: 1) Building on the ESS proton accelerator, which is the world's most powerful, ESSnuSB+ would create a uniquely high neutrino flux, increasing possibility to obtain unique data. 2) The distance to the detectors at the Zinkgruvan mine, in combination with the high neutrino flux, and the large detector volume, would maximise measurement sensitivity, thereby providing unparallelled opportunities for the study of neutrinos. The ongoing Horizon Europe project ESSnuSB+ (2023 - 2026), will perform complementary studies to prepare the ground for ESSnuSB, perform civil engineering studies for the implementation of the facility in the ESS site and the implementation of the far detector near Zinkgruvan mine, and also liaise with industrialists to prepare for further R&D work. Among technological systems included in the ESSnuSB design: an intense H- ion source, a Radio Frequency Quadrupole (RFQ) accelerator stage, modulator capacitors for the ESS linear accelerator, dipole, quadrupole and sextupole magnets, vacuum tubes, collimators and vacuum pumps for the accumulator, high-current generators 350 kA and strip-lines for the toroidal magnet horn, a granular beam-target, scintillator detectors for the beam-dump, a large number (100’000) of photomultipliers, a high capacity water cleaning systems, read-out electronics for the neutrino detectors, control electronics and processors, radiation monitors, survey equipment, ventilation systems, and draining systems. For further details, please see the ESSnuSB conceptual design report on the website www.essnusb.eu ESSnuSB+ REPRESENTATIVES AT BIG SCIENCE SWEDEN: Tord Ekelöf, Scientific leader, ESSnuSB+, Uppsala University, Maja Olvegård, WP leader, ESSnuSB+, FREIA Laboratory, Uppsala University, Colin Carlile, ESSnuSB+, Lund University, Mamad Eshraqi, ESSnuSB+, ESS, Natalia Milas, ESSnuSB+, ESS