Commissioning of the University of Maryland Electron Ring (UMER): Advances toward multiturn operation

The University of Maryland Electron Ring (UMER) is a low-energy, high current recirculator for beam physics research [ M. Reiser , in Proceedings of the 1999 Particle Accelerator Conference, New York, NY (IEEE, New York, 1999 ), p. 234 ]. Ring construction is completed for multiturn operation of beams over a broad range of intensities and initial conditions. UMER is an extremely versatile experimental platform with a beam current of up to 100 mA and a pulse length as long as 100 ns . UMER is addressing issues in beam physics relevant to many applications that require intense beams of high quality, such as advanced concept accelerators, free electron lasers, spallation neutron sources, and future heavy-ion drivers for inertial fusion. The primary focus of this paper is to present experimental results in the areas of beam steering and multiturn operation of the ring. Unique beam steering algorithms now include measurement of the beam response matrix at each quadrupole and matrix inversion by singular value decomposition. With these advanced steering methods, transport of an intense beam over four turns (144 full lattice periods) of the ring has been achieved.