AFIS - Antiproton Flux In Space

AFIS is an experiment being designed, built, and conducted by students at E18. Its objective is the development of a particle detector with an innovative and new design, which shall measure the flux of antiprotons in Low Earth Orbit aboard the nano-satellite MOVE 2.

Project homepage:

Contact: info [at]

Scientific Background

Predicted and measured antiproton flux for a satellite in Low Earth Orbit (~ 600 - 800 km).

The understanding of the interactions and the transport mechanisms of cosmic rays through the interstellar medium and through the heliosphere of our sun is a fundamental question of astroparticle physics. For accurate investigations on the creation of primary cosmic rays it is necessary to know the processes that occur during the transport of these particles from their origin to Earth. A promising approach for testing our understanding of these processes is the research on cosmic ray antimatter. Since there is no primary source of antiparticles in the universe known to us until today, the only production mechanisms are via inelastic processes of other high-energy cosmic ray particles. A comparison of experimentally measured fluxes with predictions derived from current transport models thus can provide indications on the validity of these models.

Due to technological advances in the last decades measurements became more and more effective. In 2011, PAMELA was the first experiment to discover geomagnetically trapped cosmic ray antiprotons, thus providing good experimental data to probe our understanding of the mechanisms of the creation of secondary antimatter particles and their trapping in Earth’s magnetic field. Although there exist some models to describe these processes, discrepancies between the measured data and the theoretical predictions remain. This could indicate to an inaccuracy of the models.

Besides antiproton measurements, the search for heavier antiparticles like antideuterons and antihelium attracted attention in the past years. The secondary production of such particles is suppressed and their existence could be a hint for dark matter annihilation or decay. Because the masses of these hypothetical dark matter particles are not known yet, the energy range of the search for their secondary decay particles is quite large. Although there are models that demand searches at low particle energies (hundreds of MeV/nucleon), most of the current particle physics experiments in space barely manage to measure in this energy region due to their design for higher particle energies.

For this reason the Antiproton Flux in Space experiment (AFIS) was established in 2012 with the aim to build a particle detector that is sensitive to low-energy charged particles. The main objective is to measure the flux of trapped low-energy antiprotons inside the South Atlantic Anomaly (SAA) with a novel CubeSat-sized active target particle detector and thus extend the measurement of the PAMELA experiment mentioned above. The detection principle is based upon the stopping and annihilation process of low energetic antiparticles inside the active detector region. By using the “Bragg Peak Spectroscopy” technique for the stopping particle and by detecting the annihilation products, particle identification and energy reconstruction can be performed.

Prototype Test on BEXUS

The AFIS team is being funded and supported by the German Aerospace Center (DLR) to conduct a technology demonstrator mission on a stratospheric research balloon as part of the REXUS/BEXUS program. The REXUS/BEXUS program is realized under a bilateral Agency Agreement between the German Aerospace Center (DLR) and the Swedish National Space Board (SNSB). Through the collaboration with the European Space Agency (ESA), the Swedish share has been made available to students from all ESA Member or Cooperating States.



For more information please visit the AFIS homepage.