Direct Measurement of Photons from the Electron–Hadron Bremsstrahlung at the EIC

Direct detection of bremsstrahlung photons, in principle, offers the most straightforward and most robust method of luminosity determination at the EIC, but requires an extraordinary performance of the photon detector. In this paper, we first discuss the extreme working conditions for such detectors at the EIC and the resulting technology choices. Then, we report on the initial results of Monte Carlo simulations, using <span class="sf">Geant4</span>, of the proposed sampling calorimeter, which is made of a copper absorber with embedded quartz fibres read out by silicon photomultipliers. Finally, the tentative requirements for appropriate readout electronics are formulated. Abstract Published by the Jagiellonian University 2025 authors