CAST turns its gaze to the sun

21 August 2002

This unusual telescope is prime example not only of the common ground between particle physics and astronomy, but also of recycled technology. CAST - the CERN Solar Axion Telescope - will search for very weakly interacting neutral particles called axions, which are a leading candidate for the 'dark matter' of the Universe, and which may be made in the hot core of the Sun. The idea behind CAST is to use a strong magnetic field to convert the solar axions back into X-ray photons. So it is using a prototype dipole magnet from the Large Hadron Collider (LHC) that is under construction at CERN, the European centre for particle physics near Geneva.

The telescope will look at the Sun through the two beam pipes, each with X-ray detectors mounted at both ends. It will view the Sun through one end when it rises, and through the other end when it sets. To reduce the X-ray background levels, the experiment is using a special X-ray lens which is a spare part from a German X-ray astronomy satellite. Indeed, about 90% of the equipment used is recycled - the cryogenics infrastructure for the superconducting dipole was previously used by the DELPHI solenoid magnet.

Credit: CERN Photo