  Beam dump experiments proposed at the SPS are perfectly suited to explore the
parameter space of models with long-lived particles, thanks to the combination
of a large intensity with a high proton beam energy. In this paper, we study
how the exploration power may be augmented further by installing a detector
based on liquid argon time projection chamber technology. In particular, we
consider several signatures of new physics particles that may be uniquely
searched for with such a detector, including double bang events with heavy
neutral leptons, inelastic light dark matter, and millicharged particles.
