The ZEPTO Dipole: Zero Power Tuneable Optics for CLIC

Permanent magnet (PM) based systems create a significantly reduced power consumption compared to conventional room temperature electromagnets. STFC and CERN are investigating the feasibility of using tuneable PM systems to reduce high electricity and water-cooling costs; plus the associated large scale infrastructure burden in the proposed CLIC accelerator. This collaboration has previously resulted in the development of two tuneable PM Quadrupole systems. We present here a continuation of this work in the development of a pure PM C-Dipole with a tuning range of over 50%. A prototype has been simulated and constructed using a single 50x40x20 cm block of NdFeB which slides horizontally to provide tuning. We outline the design, construction and measurement of a prototype dipole and discuss its suitability as a replacement for electromagnetic systems. Issues including field homogeneity over a large tuning range and the management of high magnetic forces are addressed.