Precision Measurement of the Proton Flux in Primary Cosmic Rays from Rigidity 1 GV to 1.8 TV with the Alpha Magnetic Spectrometer on the International Space Station


A precise measurement of the proton flux in primary cosmic rays with rigidity (momentum/charge) from 1 GV to 1.8 TV is presented based on 300 million events. Knowledge of the rigidity dependence of the proton flux is important in understanding the origin, acceleration, and propagation of cosmic rays. We present the detailed variation with rigidity of the flux spectral index for the first time. The spectral index progressively hardens at high rigidities.

Supplemental Material
Download AMS Data

The proton flux as a function of rigidity at the top of AMS including errors due to statistics (stat); contributions to the systematic error from the trigger (trig); acceptance, background contamination, geomagnetic cutoff, and event selection (acc); the rigidity resolution function and unfolding (unf); and the absolute rigidity scale (scale); and the total systematic error (syst).

External Databases
AMS Data at CRDB (Cosmic-ray DataBase)

The CRDB at LPSC/IN2P3/CNRS, online since 2013, is fully described in Maurin et al. (2014, 2020)

AMS Data at Cosmic Ray DataBase (CRDB) © SSDC

The CRDB © SSDC is developed at the Space Science Data Center, a facility of the Italian Space Agency (ASI).