The October 2010 issue reported on the final steps of the unique AMS detector en route to the International Space Station. Powered up the following year, AMS continues to make precision measurements of charged cosmic rays.
The Alpha Magnetic Spectrometer (AMS), an experiment that will search for antimatter and dark matter in space, left Geneva on 26 August on the penultimate leg of its journey to the International Space Station (ISS). Following work to reconfigure the AMS detector at CERN, it was flown to the Kennedy Space Center in Florida on board a US Air Force Galaxy transport aircraft.
The AMS experiment 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 programme that is complementary to that of CERN’s LHC.
Last February the AMS detector travelled from CERN to the European Space Research and Technology Centre (ESTEC) in Noordwijk for testing to certify its readiness for travel into space (CERN Courier April 2010 p5). Following the completion of the testing, the AMS collaboration decided to return the detector to CERN for final modifications. In particular, the detector’s superconducting magnet was replaced by the permanent magnet from the AMS-01 prototype, which had already flown in space in 1998. The reason for the decision was that the operational lifetime of the superconducting magnet would have been limited to three years because there is no way of refilling the magnet with liquid helium – which is necessary to maintain the magnet’s superconductivity – on board the space station. The permanent magnet, on the other hand, will now allow the experiment to remain operational for the entire lifetime of the ISS.
Following its return to CERN, the AMS detector was reconfigured with the permanent magnet before being tested with particle beams. The tests were used to validate and calibrate the new configuration before the detector leaves Europe for the last time.
On arrival at the Kennedy Space Center, AMS will be installed in a clean room for further tests. A few weeks later, the detector will be moved to the space shuttle. NASA is planning the last flight of the space-shuttle programme, which will carry AMS into space, for the end of February 2011.
Once docked to the ISS, AMS will search for antimatter and dark matter by measuring cosmic rays. Data collected in space by AMS will be transmitted to Houston and on to CERN’s Prévessin site, where the detector control centre will be located, as well as to a number of regional physics-analysis centres set up by the collaborating institutes.
• The AMS experiment stems from a large international collaboration, which links the efforts of major European funding agencies with those in the US and China. The detector components were produced by an international team, with substantial contributions from CERN member states (Germany, France, Italy, Spain, Portugal and Switzerland), and from China (Taipei) and the US. The detector was assembled at CERN, with the assistance of the laboratory’s technical services.
- This article was adapted from text in CERN Courier vol. 50, October 2010, p5