In-situ calibration of forward hadron calorimeters of CMS at LHC

Physical possibility for bending the LHC protons (or ions) a huge angle of 1-20 degrees in the energy range of 0.45 to 7 TeV by means of a bent channeling crystal of Silicon or Germanium is demonstrated. Such an application can be useful for calibration of CMS (or ATLAS) calorimeters in situ by the LHC beam of precisely known energy. We show by simulations that such an application would be feasible at the LHC, and report the experience of IHEP Protvino in bending 70 GeV protons by 9 degrees (150 mrad) during 10 years in 1994-2004 experiments.