On 24 September 1999 the French authorities gave their formal permission for CERN’s LEP electronpositron collider to run at beam energies of up to 105 GeV. Immediately following the receipt of the letter, two fills were running at 101 GeV. However, the machine then had cryogenics problems.
LEP had been running impressively at 100 GeV per beam (a collision energy of 200 GeV) since early August.
