• P.S. Yoon
  Rochester University, Rochester, New York
• C.L. Bohn
  Northern Illinois University, DeKalb, Illinois
• W. Chou
  Fermilab, Batavia, Illinois

Individual particle orbits in a beam will respond to both external focusing and accelerating forces as well as internal space-charge forces. The external forces will reflect unavoidable systematic and random machine errors, or imperfections, such as jitter in magnet and radio-frequency power supplies, as well as magnet translation and rotation alignment errors. The beam responds in a self-consistent fashion to these errors; they continually do work on the beam and thereby act as a constant source of energy input. Consequently, halo formation and emittnace growth can be induced, resulting in beam degradation and loss. We have upgraded the ORBIT-FNAL package and used it to compute effects of machine errors on emittance dilution and halo formation in the existing FNAL-Booster synchrotron. This package can be applied to study other synchrotrons and storage rings, as well.

• J.W.  Staples, R. Keller, A. Sessler
  LBNL, Berkeley, California
• W. Chou
  Fermilab, Batavia, Illinois
• P.N. Ostroumov
  ANL, Argonne, Illinois

Accelerator-driven High-Energy Density Physics experiments require typically 1 nanosecond, 1 microcoulomb pulses of mass 20 ions accelerated to several MeV to produce eV-level excitations in thin targets, the "warm dense matter" regime. Traditionally the province of induction linacs, RF-based acceleration may be a viable alternative with recent breakthroughs in accelerating structures and high-field superconducting solenoids. A reference design for an RF-based accelerator for HEDP research is presented using 15 T solenoids and multiple-gap RF structures configured with either multiple parallel beams (combined at the target) or a single beam and a small stacking ring that accumulates 1 microcoulomb of charge. In either case, the beam is ballistically compressed with an induction linac core providing the necessary energy sweep and injected into a plasma-neutralized drift compression channel resulting in a 1 mm radius beam spot 1 nanosecond long at a thin foil or low-density target.

• W. Chou, D. Wildman
  Fermilab, Batavia, Illinois
• A. Takagi
  KEK, Ibaraki
• H. Zheng
  CALTECH, Pasadena, California

A wideband RF system (the barrier RF) has been built and installed in the Fermilab Main Injector. The cavities are made of low Q Finemet cores. The modulators use high voltage fast solid-state switches. It can generate ±7 kV single square voltage pulses. It is used to stack two proton batches to double the bunch intensity for pbar production. The stacked high intensity beams have been successfully accelerated to 120 GeV with small losses. A new test to continuously stack 12 batches for the NuMI experiment is under way.

• W. Chou, A.I. Drozhdin, C. Hill, M.A. Kostin, J.-F. Ostiguy, Z. Tang
  Fermilab, Batavia, Illinois
• H.C. Bryant
  UNM, Albuquerque, New Mexico
• R.J. Macek
  LANL, Los Alamos, New Mexico
• G. Rees
  CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
• P.S. Yoon
  Rochester University, Rochester, New York

Fermilab is working on the design of an 8 GeV superconducting RF H^- linac called the Proton Driver. The energy of the H^- beam is an order of magnitude higher than any existing H^- beams. This brings up a number of new challenges to the transport, stripping and injection into the next machine (the Main Injector), such as blackbody radiation stripping, magnetic field and residual gas stripping, Stark states of hydrogen atoms, foil stripping efficiency, single and multiple Coulomb scattering, energy deposition, foil heating and stress, radiation activation, collimation, jitter correction, etc. This paper will give a summary of these studies.*

*For details the reader is referred to FERMILAB-TM-2285-AD-T.