• M. Holloway, T.F. Godlove, P.G. O'Shea, B. Quinn, M. Walter
  IREAP, College Park, Maryland
• M. Reiser
  University Maryland, College Park, Maryland

Progress is described toward the development of pulse generators required for injection and extraction of the University of Maryland Electron Ring (UMER). The geometry, described elsewhere, employs a fast ironless dipole at the junction of a Y-shaped section of the ring. The dipole as developed has an inductance of 600 nH. The required +21 A, long pulse generator for multi-turn operation is installed. A pulser providing -42 A for deflection in the opposite sense during injection is under development. It must have a fall time of ~100 ns in view of the 200 ns circulation time for the beam. A similar pulser, having a 100 ns risetime is required for beam extraction. The fast pulsers employ MOSFET switches.

• B. Quinn, G. Bai, S. Bernal, T.F. Godlove, I. Haber, J.R. Harris, M. Holloway, H. Li, J.G. Neumann, P.G. O'Shea, K. Tian, M. Walter
  IREAP, College Park, Maryland
• M. Reiser
  University Maryland, College Park, Maryland

Commissioning of the University of Maryland Electron Ring (UMER) is underway (see general abstract on UMER). We discuss the various electrical systems of UMER. The power system includes 114 supplies for 70 air-core magnetic quadrupoles, 36 bending dipoles and 30+ steering dipoles as well as earth's field compensating coils. Systems for data collection comprise multiplexers and fast digitizers for diagnostics including 15 fast beam position monitors (BPMs)and video capture from fluorescent screen monitors. Several pulsers have been built in-house for injection and extraction magnets. The stringent timing schemes are also presented.

• M. Walter, G. Bai, S. Bernal, I. Haber, M. Holloway, R.A. Kishek, P.G. O'Shea, B. Quinn
  IREAP, College Park, Maryland
• M. Reiser
  University Maryland, College Park, Maryland

The injection line and main lattice for the University of Maryland Electron Ring (UMER) has been completed. The electron beam has been guided around the full 360 degrees of the ring. Beam steering and matching in the injection line is achieved with six quadrupole magnets and several small steering dipole magnets. The dipole component of an offset quadrupole and a pulsed dipole are used to achieve the 10 degree bend required from the injection line into the ring. The pulsed dipole is designed to operate with a short pulse (2 kV, -30 A, 100 ns flat top duration) for injection superimposed on a long pulse (300 V, 15 A, 20·10^-6 s duration) for multiple beam passes. The beam is controlled in the recirculating ring with a regular lattice of 36 dipole and 72 quadrupole magnets. Initial experimental results of the beam transport and control will be presented.

• S. Bernal, G. Bai, D.W. Feldman, R. Feldman, T.F. Godlove, I. Haber, J.R. Harris, M. Holloway, R.A. Kishek, J.G. Neumann, P.G. O'Shea, C. Papadopoulos, B. Quinn, D. Stratakis, K. Tian, J.C. Tobin Thangaraj, M. Walter, M. Wilson
  IREAP, College Park, Maryland
• M. Reiser
  University Maryland, College Park, Maryland

The University of Maryland electron ring (UMER) is a low-energy, high current recirculator for beam physics research. The ring is completed for multi-turn operation of beams over a broad range of intensities and initial conditions. UMER is addressing issues in beam physics with relevance to many applications that rely on intense beams of high quality. Examples are advanced accelerators, FEL’s, spallation neutron sources and future heavy-ion drivers for inertial fusion. We review the motivation, ring layout and operating conditions of UMER. Further, we present a summary of beam physics areas that UMER is currently investigating and others that are part of the commissioning plan: from transverse beam dynamics (matching, halo formation, strongly asymmetric beams, space-charge waves, etc), longitudinal dynamics (bunch capture/shaping, evolution of energy spread, longitudinal space-charge waves, etc.) to future upgrades and planned research (acceleration and resonance traversal, modeling of galactic dynamics, etc.) We also emphasize the computer simulation work that is an integral part of the UMER project.