CNGS beam monitor with the LVD detector

The importance of an adequate CNGS beam monitor at the Gran Sasso Laboratory has been stressed in many papers. Since the number of internal νμ CC and NC interactions in the various detectors will not allow rapid collection of statistics, one should also be able to detect the νμ CC interactions in the upstream rock. In this study we have investigated the performances of the LVD detector as a monitor for the CNGS neutrino beam. Thanks to its wide area (13×11 m2 orthogonal to the beam direction), LVD can detect about 120 muons per day originated by νμ CC interactions in the rock. The LVD total mass is ∼ 2 kt. This allows obtaining 30 more CNGS events per day as internal (NC + CC) νμ interactions, for a total of ∼ 150 events per day. A 3% statistical error can be reached in 7 days. Taking into account the time characteristics of the CNGS beam, the cosmic muon background can be reduced to a negligible level, of the order of 1.5 events per day.