Operational test and field measurement of prototype bending magnets for energy saver/Doubler project

A full scale 22-foot Energy Doubler bending magnet (E22-1A) was tested in a subcooled liquid helium system. Most of the key magnetic field measurements were done on this magnet. A five-foot precision model magnet (E5-1) was tested in pool boiling helium. Much more systematic and precise measurements were done on this magnet, which was excited up to 45.7 kG at the center of the beam bore. The measurements of both magnets were done on training and quench behavior, ac loss of the magnet, and field measurements with a Hall probe. Using an NMR of a Li sample, absolute field value up to 44 kG was confirmed. Extensive harmonic analysis were done for both magnets for DC and pulsed modes. Remanent field was measured with a Hall probe and also by harmonic coil, and its variation with negative bias field was studied. The magnetically vertical plane and an effective magnetic length were measured with a stretched wire coil.