AMS prepares for long stay in space

Following the successful space qualification tests at the ESA Technology Centre (ESTEC) in Noordwijk in the Netherlands, AMS is now back in the integration hall at CERN Prévessin. The collaboration is replacing the superconducting magnet with a permanent (non-superconducting) one, which will ensure reliable operation of the experiment for the recently planned longer run on board the International Space Station (ISS).

Work is under way at the AMS integration hall at CERN Prévessin.

Following a trip to ESTEC in Noordwijk in the Netherlands, where tests confirmed its fitness for launch into space on board the International Space Station (ISS), the AMS experiment is now back at CERN for final modifications. “The collaboration agreed to adopt a modified configuration that, among other things, re-uses the permanent magnet of the AMS-01 prototype that was flown into space in 1998”, says Samuel Ting, Spokesperson of the AMS experiment. Although less powerful, this magnet will allow AMS to function as long as the ISS remains in space, i.e. at least until 2020 and possibly until 2028, in line with the plans to extend the Station's lifetime set out by President Obama in February this year.

With the superconducting magnet, AMS's lifetime was initially expected to be around three years due to restrictions on the quantity of liquid helium needed to cool it that could be transported. However, recent tests carried out both at CERN and at ESTEC have shown that the actual lifetime would actually have been closer to two years. “There is no way to refill the magnet with superfluid helium on the Space Station, due to the termination of the shuttle programme at the end of 2010. This important fact, combined with the significant extension of the ISS's lifetime, convinced us to change the magnet”, explains Samuel Ting.

During the coming weeks, AMS will be reconfigured with the permanent magnet in a clean room in Prévessin. The magnet is the key component of a particle detector, serving to curve the trajectory of the charged particles so that they can be identified. The strength of the magnetic field is an important parameter determining the detector's resolution. “To compensate the magnet’s weaker field, physicists will add additional sensors to make sure that the two magnet systems have nearly identical momentum resolution. The increased data acquisition time will greatly improve the detector’s sensitivity in the search for antimatter and Dark Matter”, he says.

AMS will be tested using CERN's particle beams over the summer, allowing the new configuration to be checked and calibrated before the detector leaves European soil for the last time in September. Mission STS-134, the flight on which the AMS will journey to the ISS, has been given a window for lift-off between 15 November and 15 December. This should be the very last flight of the US space shuttle programme.

by CERN Bulletin