Samuel Ting

Search for Antimatter in the Universe

Tuesday, 27 June 2000
14:30 - 15:00 CEST


The Alpha Magnetic Spectrometer (AMS) is a high energy physics experiment scheduled for installation as the major scientific payload onboard the International Space Station (ISS). As the first orbiting magnetic spectrometer, AMS has been designed to study some of the most fundamental questions in physics and astrophysics which include: -the determination of the existence or absence of antimatter in the universe through the detection of anticarbon, antihelium or heavier nuclei; the study of the origin and structure of dark matter which makes up 90% of he universe and; -the study of the origin and composition of cosmic rays.

In recent decades, much has been learned about microwaves, x-rays and gamma ray photons from the remarkable observations and experiments conducted with powerful landbased and freeflying satellites and telescopes. However no experiment to date has had the range or sensitivity to detect and identify charged particles originating from outside our own Milky Way galaxy. There has never been a magnetic spectrometer in space which can identify the electric charge of cosmic rays by identifying their trajectories in a magnetic field. This feature distinguishes AMS from balloon experiments which have been limited by their short duration, low statistics and the simple fact that charged particles are absorbed by the Earth’s atmosphere.

In preparation for this long duration mission on the ISS, AMS flew a precursor mission on board the space shuttle Discovery (STS91) in June 1998. During this flight, AMS recorded the tracks of millions of cosmic particles at latitudes 320-390 km above the Earth yielding unexpected findings. Physics results from this ten day mission are presented.

The AMS detector which will be deployed on the International Space Station will feature a superconducting magnet and a more complex array of particle detectors than in the configuration flown on the precursor flight. This technically enhanced version of the AMS detector will be flown in September 2003 to the ISS.

The AMS experiment merges elementary particle physics and astrophysics. It is an international collaboration composed of 34 universities and research institutes from Germany, France, Switzerland, Italy, Finland, Taiwan and China. The collaboration is working with leading aerospace industries to ensure the technical success of this project in the hostile environment of space and with NASA to meet all safety, power and weight requirements. AMS is sponsored by the United States Department of Energy and the National Aeronautics and Space Administration as well as funding agencies in Europe and Asia.

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