ISOTOPIC MASS SEPARATION WITH THE RICH DETECTOR OF THE AMS EXPERIMENT

The Alpha Magnetic Spectrometer (AMS) to be installed on the InternationalSpace Station (ISS) will be equipped with a proximity focusing Ring ImagingCerenkov detector (RICH). Reconstruction of theˇ Cerenkov angle and the electricˇcharge with RICH are discussed. A likelihood method for the Cerenkov angleˇreconstruction was applied leading to a velocity determination for protons with aresolution around 0.1%. The electric charge reconstruction is based on the countingof the number of photoelectrons and on an overall efficiency estimation on an event-by-event basis. The isotopic mass separation of helium and beryllium is presented.