• S. Redaelli, M.C. Alabau Pons, K. Fuchsberger, M. Giovannozzi, M. Lamont, G.J. Müller, F. Schmidt
  CERN, Geneva
• X. Buffat
  EPFL, Lausanne

The con­trol of the high in­ten­si­ty beams of the CERN Large Hadron Col­lid­er (LHC) is par­tic­u­lar chal­leng­ing and re­quires a pre­cise knowl­edge of the crit­i­cal beam and ma­chine pa­ram­e­ters. In re­cent years ef­forts were de­vot­ed to the de­sign of a soft­ware in­fras­truc­ture aimed at mim­ick­ing the be­hav­ior of the LHC. An on­line model of the ma­chine, based on the ac­cel­er­a­tor de­sign tool MADX, has been de­vel­oped to sup­port the com­mis­sion­ing and the op­er­a­tion of the LHC. This model is in­te­grat­ed into the JA­VA-based LHC soft­ware frame­work and pro­vides the full com­put­ing power of MADX, in­clud­ing the best knowl­edge of the ma­chine aper­ture and mag­net­ic mod­els. The MADX im­ple­men­ta­tion is serv­er-based and pro­vides var­i­ous fa­cil­i­ties for op­tics com­pu­ta­tion to other ap­pli­ca­tion clients. In this paper, we pre­sent the sta­tus of the MADX on­line ap­pli­ca­tion and il­lus­trate how it has been used dur­ing the LHC com­mis­sion­ing. Pos­si­ble fu­ture im­ple­men­ta­tions are also dis­cussed.