AMS Readies for Dark-Matter Mission

The Alpha Magnetic Spectrometer (AMS) has taken its initial steps in a journey that will take it ultimately to the International Space Station (ISS), where it will be used to look for signs of dark matter.

The instrument left CERN (European Organization for Nuclear Research) in a special convoy that is due to arrive at the European Space Agency's research and technology center, ESTEC, at Noordwijk, the Netherlands, in about a week. Once there, the detector will undergo testing of its ability to survive a shuttle lift-off and to operate in space. Twenty members of the AMS collaboration will accompany the detector on its journey.

International Space Station / NASA

Construction of the AMS detector components was carried out by an international team with significant contributions from CERN member states France, Germany, Italy, Portugal, Spain and Switzerland, as well as China, US, and Taipei, Taiwan. Assembly was carried out at CERN with help from the laboratory’s engineering services. The detector was put through its paces using a test beam from the Super Proton Synchrotron accelerator –the first of a series of tests on the fully assembled detector. The instrument performed well, demonstrating its ability to work as a coherent whole once it reaches space.

A beam of primary protons from the synchrotron was used to check the detector’s momentum resolution, and it qualified the spectrometer’s ability to measure particle curvature and momentum. The spectrometer’s ability to distinguish electrons from protons also was tested. This is very important for the measurement of cosmic rays, 90 percent of which are protons and constitute a natural background for other signals that AMS scientists are interested in. AMS will be looking for an abundance of positrons and electrons from space, one of the possible markers for dark matter.

Once at ESTEC, the instrument will be placed in the European Space Agency’s thermovacuum room, which simulates space vacuum, to test the detector’s capacity of exchanging heat. Testing the spectrometer’s ability to maintain its thermal balance is essential for the functioning of the detector’s electronics and especially of its unique superconducting magnet, which is the first of its kind to be launched into space.

“This is a very important milestone for AMS, as it’s the first time that it is going to be tested in vacuum. After the test, AMS may come back to CERN for a final check and then it’s off to the Kennedy Space Center for launch,” said Prof. Sam Ting, the experiment’s Nobel-prize winning spokesman. “The contribution of CERN has been crucial. Without the work of CERN’s accelerator, magnet and vacuum groups we wouldn’t be at this stage here today.”

AMS will leave ESTEC towards the end of May aboard a special US Air Force flight to the Kennedy Space Center in Florida. Lift-off aboard the space shuttle Discovery is scheduled for July. Once docked to the ISS, AMS will examine fundamental issues about matter and the origin and structure of the universe directly from space. Its main scientific target is the search for dark matter and antimatter in a program that is complementary to that of the Large Hadron Collider. AMS data from space will be transmitted from the ISS to Houston, Texas, and on to the detector control center at CERN, as well as to several regional physics analysis centers set up by the collaborating institutes.

For more information, visit: ams.cern.ch