AMS measures indication of dark matter
The Alpha Magnetic Spectrometer (AMS-02) onboard the ISS space station has observed a strikingly large number of positrons in cosmic radiation. Positrons are subatomic antiparticles of electrons. These antiparticles are possibly created when two dark matter particles collide and destroy each other. The excess of positrons that the AMS-02 found in cosmic radiation therefore provides an indication that the detector measured an indication of dark matter.
Dark matter has never previously been observed, even though more than one quarter of the universe consists of this form of matter. The discovery by the AMS-02 could therefore be the first indirect detection of dark matter. Whether the positrons actually originate from dark matter is not yet certain. They might also originate from pulsars. In the coming months the researchers hope to be able to give an answer to the origin of the positrons.
In any case the discovery confirms that the AMS-02 is functioning well. Eleven years ago Nikhef designed a new cooling concept for the detector: CO2 cooling. This type of cooling ensures that considerably less material is present in the detector compared with other coolants. The National Aerospace Laboratory of the Netherlands further developed the AMS-02 cooling concept designed by Nikhef and eventually constructed it as well.
Bart Verlaat, engineer at the Mechanical Technology Department of Nikhef is still involved in the project. In 2010, he helped to test the system in the Space Simulator at the European Space Agency and subsequently in 2011 he helped with the tests of the cooling system in space from the Mission Control Center of NASA in Houston. "I am glad to hear that AMS has shown positive scientific results. Hopefully the good functioning of our cooling system has contributed to that. The cooling system is functioning better than expected. Since the start of the mission the temperature of the detector has remained stable at 0°C. We have therefore not had to adjust it as expected due to the changing thermal environment in space," says Verlaat.
Source
Press release CERN.
Reference
First Result from the Alpha Magnetic Spectrometer on the International Space Station: Precision Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5–350 GeV, M. Aguilar et al. (AMS Collaboration), Phys. Rev. Lett. 110, 141102 (2013).