The Alpha Magnetic Spectrometer (AMS) is a large acceptance magnetic spectrometer to search in space for antinuclei in cosmic rays with a sensitivity 10⁴ times better than achieved previously. In its first mission, AMS went into a ten day orbit on the Space Shuttle Discovery in June 1998. In this paper we briefly report on the detector performance during this first flight.

PACS numbers: 95.55.Vj, 98.70.Sa