LEIR was first proposed in 1993[2] but it wasn't until 2003 that work to transform the old experiment into the new accelerator was started.

[5] During 2017, LEIR was running with xenon ions, sending them normally to SPS and, exceptionally to the LHC[6] for one day of physics.

In 2018, the machine was running again with lead ions and had the objective to reach an LIU performance of more than 9×1010 charges extracted.

On 6 June 2018 that performance was achieved and also a new extraction record of 10.35×1010 charges was accomplished.

The most important function of LEIR is not acceleration, but electron cooling to reduce the emittance of the ion beam in order to maintain high luminosity of the final LHC beam.