https://doi.org/10.1051/epjconf/202532000011
A Pointing Electromagnetic Calorimeter for FIP Experiments leveraging X → γγ Decays
1 Institut für Physik and PRISMA+ Cluster of Excellence, Johannes Gutenberg-Universität, Mainz, Germany
2 PRISMA+ Cluster of Excellence, Johannes Gutenberg-Universität, Mainz, Germany
* e-mail: sebastian.ritter@cern.ch
Published online: 7 March 2025
This paper describes the design and validation of a pointing electromagnetic calorimeter (ECAL) for the precise reconstruction of X → γγ decays in beam dump experiments, specifically targeting feebly interacting particles (FIPs) as in the SHiP experiment. GEANT4 simulation demonstrates that the ECAL, featuring 1 cm wide scintillator strips interleaved with iron absorber plates, achieves an angular resolution of 12 mrad at 20 GeV as well as an energy resolution with a stochastic term of approximately 11% per GeV. Both figures show minimal dependence on the incident angle of the photons. To validate the simulation a conceptual prototype has been built. Test beam data taken at DESY closely match the simulation results and indicate further potential improvements in pointing resolution. The combined Monte Carlo and test beam results confirm the feasibility of the proposed design for X → γγ reconstruction.
© The Authors, published by EDP Sciences, 2025
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
