The synchrocyclotron was CERN's first accelerator, operational since 1957. While CERN is a champion in recycling (eg. the Proton Synchrotron accelerator is operational since 1959 and still curcial in delivering protons to the LHC), the synchrocyclotron deliverd “only” 33 years beams for science. The simple principles of alternating acceleration and bending in half circles are also what powers many cyclotrons in hospitals and other places nowadays.

One of the first science results was the discovery of the charged pion → e + neutrino decay, a rare decay mode with probability ~10^(-4), whereas the similar decay to muon and neutrino has probability near 1. The reason for the very different behaviour of electron and muon lies in something called helicity suppression – you may have worked through the math yourself before. Back in those days, this was a discovery-level result.

Since a few years, this first accelerator has been made into a beautiful exhibition item, reminiscing some of CERN's early history.

A page with some info is here:
https://home.cern/science/accelerators/synchrocyclotron