The Electron-Ion Collider (EIC) at Brookhaven National Laboratory is the next-generation US facility for “cold QCD” science, which includes understanding
the origin of the mass and spin of the proton and other hadrons, nuclear binding, and the spatial structure of the glue in nucleons and nuclei. The latter also constitutes an important input for the initial state in heavy-ion collisions (“hot QCD”). The EIC will be the first collider capable of storing polarized electron, protons, and light ions. It will also be able to accelerate all ions from deuterium to uranium. To support this extensive program, the collider will need one, and preferably two, general-purpose detectors. A unique challenge of the EIC detector is the inherent asymmetry between the two beam directions, both in terms of particle species and momenta, and the physics (low-x jets, for instance, go in the electron beam direction while high-x jets go in the hadron beam direction). The resulting detector thus not only needs a fully hermetic suite of subsystems for tracking, calorimetry, and particle identification (which is of particular importance to EIC physics), but also needs to satisfy very different requirements at different angles (pseudo-rapidities) – and it needs to accomplish this with a moderate budget. This presentation will briefly cover the key physics opportunities at the EIC, followed by a detailed look at an affordable compact EIC detector concept, which makes it possible to reach the performance goals. As the name suggests, it does this by employing a combination of technologies that allows reducing cost by reducing subsystem size rather than compromising quality. The compact design is also beneficial for subsystem integration and integration into the interaction region of the accelerator.