FINESSE: A Versatile Beamline for Fundamental Interactions with Neutrons at the European Spallation SourcE
Abstract
FINESSE (A Versatile Beamline for \textbf{F}undamental \textbf{I}nteractions with \textbf{N}eutrons at the \textbf{E}uropean \textbf{S}pallation \textbf{S}ourc\textbf{E}) is a proposed versatile beamline for fundamental interactions with neutrons at the European Spallation Source. Building on the HIBEAM design studies, FINESSE extends the original concept into a dual-guide beamline capable of operating either in a high-flux configuration or in a low-background configuration within a single ESS beam port. The high-flux branch is optimized for rare-process searches, including neutron--antineutron oscillations, neutron--sterile-neutron transitions, axion-like-particle searches, neutron charge measurements, and rare neutron decays. The low-background branch is designed for precision measurements requiring strong suppression of prompt and line-of-sight backgrounds, with a cryogenic neutron electric-dipole-moment experiment used as a benchmark case. A baseline exchangeable-guide concept has been developed in which only short guide sections inside the ESS bunker are exchanged, while the upstream extraction system and chopper positions remain fixed. A staged implementation, Short FINESSE, would use the upstream section of the high-flux beamline together with a compact magnetically controlled experimental region, enabling an early physics and R\&D programme before completion of the full facility. This paper summarizes the scientific case, beamline concept, guide simulations, chopper and timing system, magnetic-field control, detector developments, and staged implementation strategy. FINESSE would establish a long-term particle-physics infrastructure at ESS, providing a beamline for both discovery-driven searches and precision neutron measurements throughout the lifetime of the facility.
Related
- Neutron Optical Constraints on Exotic Parity-odd Interactions between Neutrons and Nucleons
- Neutron Double-Differential Cross Sections for Spallation Reactions from an ANN Model
- Altermagnetism revealed by polarized neutrons in MnF 2
- On imaging capabilities of the Imaging and Medical beamline at the Australian Synchrotron
- Automated end-station at the soft X-ray beamline featuring robotic air-to-ultrahigh-vacuum sample transfer, scanning probe spectroscopy, and machine learning analysis
BibTeX
@misc{amaral2026finesse,
title = {{FINESSE: A Versatile Beamline for Fundamental Interactions with Neutrons at the European Spallation SourcE}},
author = {J. Amaral and J. Barrow and M. Bartis and D. H. Beck and P. M. Bentley and J. Bijnens and G. Brooijmans and L. J. Broussard and A. Burgman and G. Cibinetto and G. Croci and D. D. Di Julio and P. Fierlinger and B. W. Filippone and C. Gatto and H. Gisbert and H. Gogoi and G. Gorini and A. Gutierrez-Rodriguez and A. Koberinski and M. Kaczmarek and M. Silarski and M. O'Riordan and A. Heinz and J. Henderson and M. Holl and H. T. Johansson and B. Jonsson and H. Henriksson and L. Jonsson and Y. Kamyshkov and M. P. Kuhl and P. Kinhult and R. Kolevatov and A. Kozela and W. T. Lee and K. K. H. Leung and T. -J. Liang and G. Luzin and B. Meirose and D. Milstead and R. Mohapatra and G. Muhrer and A. Muraro and A. Nepomuceno and N. Okada and A. Oskarsson and T. Palasz and R. Pasechnik and V. Larsson and L. B. Persson and O. Putignano and J. Ramsey and C. Snow and L. Werselius and B. Rataj and A. Rodriguez-Sanchez and A. Saunders and V. Santoro and F. Scioscioli},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.17373},
eprint = {2610.17373},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.17373},
}
RIS
TY - UNPB
TI - FINESSE: A Versatile Beamline for Fundamental Interactions with Neutrons at the European Spallation SourcE
AU - J. Amaral
AU - J. Barrow
AU - M. Bartis
AU - D. H. Beck
AU - P. M. Bentley
AU - J. Bijnens
AU - G. Brooijmans
AU - L. J. Broussard
AU - A. Burgman
AU - G. Cibinetto
AU - G. Croci
AU - D. D. Di Julio
AU - P. Fierlinger
AU - B. W. Filippone
AU - C. Gatto
AU - H. Gisbert
AU - H. Gogoi
AU - G. Gorini
AU - A. Gutierrez-Rodriguez
AU - A. Koberinski
AU - M. Kaczmarek
AU - M. Silarski
AU - M. O'Riordan
AU - A. Heinz
AU - J. Henderson
AU - M. Holl
AU - H. T. Johansson
AU - B. Jonsson
AU - H. Henriksson
AU - L. Jonsson
AU - Y. Kamyshkov
AU - M. P. Kuhl
AU - P. Kinhult
AU - R. Kolevatov
AU - A. Kozela
AU - W. T. Lee
AU - K. K. H. Leung
AU - T. -J. Liang
AU - G. Luzin
AU - B. Meirose
AU - D. Milstead
AU - R. Mohapatra
AU - G. Muhrer
AU - A. Muraro
AU - A. Nepomuceno
AU - N. Okada
AU - A. Oskarsson
AU - T. Palasz
AU - R. Pasechnik
AU - V. Larsson
AU - L. B. Persson
AU - O. Putignano
AU - J. Ramsey
AU - C. Snow
AU - L. Werselius
AU - B. Rataj
AU - A. Rodriguez-Sanchez
AU - A. Saunders
AU - V. Santoro
AU - F. Scioscioli
PY - 2026
DA - 2026/10/12
PB - arXiv
DO - 10.48550/arxiv.2610.17373
UR - https://arxiv.org/abs/2610.17373
AB - FINESSE (A Versatile Beamline for \textbf{F}undamental \textbf{I}nteractions with \textbf{N}eutrons at the \textbf{E}uropean \textbf{S}pallation \textbf{S}ourc\textbf{E}) is a proposed versatile beamline for fundamental interactions with neutrons at the European Spallation Source. Building on the HIBEAM design studies, FINESSE extends the original concept into a dual-guide beamline capable of operating either in a high-flux configuration or in a low-background configuration within a single ESS beam port. The high-flux branch is optimized for rare-process searches, including neutron--antineutron oscillations, neutron--sterile-neutron transitions, axion-like-particle searches, neutron charge measurements, and rare neutron decays. The low-background branch is designed for precision measurements requiring strong suppression of prompt and line-of-sight backgrounds, with a cryogenic neutron electric-dipole-moment experiment used as a benchmark case. A baseline exchangeable-guide concept has been developed in which only short guide sections inside the ESS bunker are exchanged, while the upstream extraction system and chopper positions remain fixed. A staged implementation, Short FINESSE, would use the upstream section of the high-flux beamline together with a compact magnetically controlled experimental region, enabling an early physics and R\&D programme before completion of the full facility. This paper summarizes the scientific case, beamline concept, guide simulations, chopper and timing system, magnetic-field control, detector developments, and staged implementation strategy. FINESSE would establish a long-term particle-physics infrastructure at ESS, providing a beamline for both discovery-driven searches and precision neutron measurements throughout the lifetime of the facility.
ER -