This is so strange. I took a tour of CERN more than a decade ago, and during the tour we were told about an experiment done there to prove antimatter responded

This is so strange. I took a tour of CERN more than a decade ago, and during the tour we were told about an experiment done there to prove antimatter responded to gravity. They described building and antimatter “fountain” where antimatter was released from an upward directed device and a detector was placed on the floor. They detected annihilations when the particles hit the detector. It sounded like a really elegant setup. I would assume the energy profile of antimatter annihilation would be quite specific and mitigate detecting other random particles. So did I dream this very detailed discovery or is this really old news?