Prototype adjustable PM quadrupole and combined function magnets

The Hybrid Electromagnet-Permanent magnet Tuneable Optics (HEPTO) prototype has been designed and built in IFAST Work Package 11.3. The prototype is a permanent magnet device designed as a direct replacement for the electromagnet dipole-quadrupole combined function magnets designed for Diamond-II. Use of permanent magnets would facilitate a reduction in operating costs and carbon footprint. The magnet design has been completed in order to meet the same magnetic field requirements in the same space envelope as the electromagnet. Unique features include mechanical shimming mechanisms, trim coils for field tuning and thermal shunts for improved temperature stability. The target integrated gradient strength and field homogeneity were achieved using the mechanical shimming to adjust the field. The trim fields provide tuning of the field but are not as efficient as was originally predicted in the design. The relative change in field strength with temperature has been reduced through the use of thermal shunt material. Future work will focus on improving the trim coil and thermal shunt designs. Work on increasing the technology readiness level will facilitate applying tuneable permanent magnet technology to future accelerators.