• O.K. Kester, G. Bollen, M.J. Johnson, M. A. Kostin, J. Ottarson, M. Portillo, S. Schwarz, C. Wilson
  NSCL, East Lansing, Michigan

The National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) is implementing a system to reaccelerate rare isotope beams from projectile fragmentation to energies of about 3 MeV/u. The reacceleration of stopped radioactive beams from projectile fragmentation at the NSCL/MSU makes use of charge state breeding in an Electron Beam Ion Trap (EBIT) to provide a compact and cost efficient system layout of MSU’s ReA3. The MSU EBIT breeder device will provide a high electron beam current density of about 10⁴ A/cm² making it well suited to rapidly increase the charge state of short-lived isotopes within tens of milliseconds or less. In addition, the breeder is optimized to provide a high storage capacity, a high beam acceptance and uses a continuous injection and beam accumulation scheme explicitly, which makes it unique. To match the beam of singly charged rare isotope ions into the acceptance of the EBIT and to analyze and purify the EBIT beams, a sophisticated beam line and diagnostic system is required. The present paper will present an overview and the status of the ReA3 EBIT.

• J. Popielarski, C. Compton, W. Hartung, M.J. Johnson, F. Marti, J.C. Oliva, R.C. York
  NSCL, East Lansing, Michigan

A medium-velocity half wave resonator has been designed and prototyped at the National Superconducting Cyclotron Laboratory for use in a heavy ion linac. The cavity is designed to provide 3.7 MV of accelerating voltage at an optimum beta = v/c = 0.53, with peak surface electric and magnetic fields of 32.5 MV/m and 79 mT, respectively. The resonant frequency is 322 MHz. The cavity was designed to reduce sensitivity to bath pressure fluctuations while maintaining a structure that can be easily fabricated, cleaned, and tuned. Deep draw forming dies and a copper cavity prototype were fabricated to confirm tolerances and formability. A prototype tuner was built; the helium vessel and power coupler have been designed. Measurements were performed to confirm finite element predictions for the mechanical modes, bath pressure sensitivity, tuner stiffness, and tuning range.