Prototype Adjustable Permanent Magnet Quadrupoles For CLIC

The 42km long Drive Beam Decelerator for the Compact Linear Collider (CLIC) requires over 41,000 quadrupole magnets. ASTeC and CERN are investigating the possibility of permanent magnet quadrupoles (PMQs) to reduce running costs and heat load inside the CLIC tunnel. A prototype of a high-strength adjustable PMQ has been built, based on a simple concept using two moving sections each containing a pair of large permanent magnets. The gradient can be adjusted within a range of 15-60 T/m (3-15T integrated gradient). The prototype has undergone extensive magnetic testing at Daresbury Laboratory and CERN, and performs well in line with expectations. A prototype of the low-strength version (0.9-9T) is currently under construction.