abstract

Two recent measurements of the \(^{12}\mathrm {C}(p,\gamma )^{13}\mathrm {N}\) reaction on natural carbon were performed by detecting \(\beta ^+\) decay of the \(^{13}\mathrm {N}\) residue. It is argued that the measurements at energies above the \(^{13}\mathrm {C}(p,n)^{13}\mathrm {N}\) reaction threshold of 3.24 MeV proton kinetic energy can be interpreted as a consequence of 1.06% admixture of the \(^{13}\mathrm {C}\) isotope in natural carbon, as the cross section for \(^{13}\mathrm {N}\) production raised by 3 orders of magnitude with respect to the measurements of \(^{12}\mathrm {C}(p,\gamma )^{13}\mathrm {N}\) at lower energies.

abstract

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 Geant4, 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.