Design and Measurement of a Low-Energy Tunable Permanent Magnet Quadrupole Prototype

The 42 km long CLIC Drive Beam Decelerator (DBD) will decelerate beams of electrons from 2.4 GeV to 240 MeV. ASTeC in collaboration with CERN has developed a novel type of tunable permanent magnet quadrupole for the DBD. Two versions of the design were produced, for the high energy and low energy ends of DBD respectively. This paper outlines the design of low energy version which has a tuning range of 3.5-43 T/m. A prototype was built at Daresbury Laboratory in 2013, and extensive measurements were carried out at Daresbury Laboratory.