Alfa is a tracking detector built to measure the absolute luminosity and total proton-proton cross section using elastic scattered protons.

Beginning of 2011, 4 RPs stations were installed in the LHC tunnel, 240m away from ATLAS : they approached the beam  down to 1-2 mm and took data during special runs. With the 2011 data the total cross section could be measured with a systematical uncertainty of about 2% . The analysis of the 2012 data is in progress.

Three PhD thesis were dedicated to this measurement within the group in 2013 :

The group contributes to the:

  • electronic
  • detector commissioning
  • beam optics
  • analysis

Contact : Patrick Puzo (staff)