• R.P. Johnson, C.M. Ankenbrandt
  Muons, Inc, Batavia
• M. Popovic
  Fermilab, Batavia

A Superconducting RF (SRF) Linac can be used for an accelerator-driven subcritical (ADS) nuclear power station to produce more than 5 GW electrical power in an inherently safe region below criticality, generating no greenhouse gases, producing minimal nuclear waste and no byproducts that are useful to rogue nations or terrorists, incinerating waste from conventional nuclear reactors, and efficiently using abundant thorium fuel that does not need enrichment. First, the feasibility of the accelerator technology must be demonstrated. We describe the Linac parameters that can enable this vision of an almost inexhaustible source of power and we discuss how the corresponding reactor technology can be matched to these parameters.

• A. Afanasev, R.J. Abrams, C.M. Ankenbrandt, K.B. Beard, R.P. Johnson, T.J. Roberts, C. Y. Yoshikawa
  Muons, Inc, Batavia
• M. Popovic
  Fermilab, Batavia

We study electron-positron in-flight annihilation as a potential source of quasi-monoenergetic photon (or gamma-ray) beams. A high-intensity tunable-energy (1.5 MeV to 15 MeV) gamma source has many potential uses in medical, industrial and security applications. Several electron-positron collision geometries are considered: a) head-on; b) collinear; and c) positron beam incident on a fixed electron target. We analyze advantages of each of the geometries in order to optimize parameters of the generated gamma-ray beams.

• R.J. Abrams, C.M. Ankenbrandt, C. Y. Yoshikawa
  Muons, Inc, Batavia

Positrons produced by electrons impinging on a target cover a broad momentum range. By bending the positrons 180° in a dipole magnetic field the momenta are dispersed according to their momenta along the exit plane of the magnet. A wedge-shaped absorber placed at the exit plane can reduce the momenta accordingly to produce a quasi-monochromatic beam of positrons. Simulation results are presented for 2 to 10 MeV/c quasi-mono-chromatic positrons produced by 75 MeV electrons on a tungsten target.

• C. Y. Yoshikawa, R.J. Abrams, A. Afanasev, C.M. Ankenbrandt, K.B. Beard
  Muons, Inc, Batavia
• D.V. Neuffer
  Fermilab, Batavia

A compact tunable gamma ray source has many potential uses in medical and industrial applications. One novel scheme to produce an intense beam of gammas relies on the ability to create a high flux of positrons. We present various positron production methods that are compatible with this approach for producing the intense beam of gammas.

• C. Y. Yoshikawa, C.M. Ankenbrandt
  Muons, Inc, Batavia
• D.V. Neuffer
  Fermilab, Batavia

Intense muon beams have many potential applications, including neutrino factories and muon colliders. However, muons are produced as tertiary beams, resulting in diffuse phase space distributions. To make useful beams, the muons must be rapidly cooled before they decay. An idea conceived recently for the collection and cooling of muon beams, namely, the use of a Quasi-Isochronous Helical Channel (QIHC) to facilitate capture of muons into RF buckets, has been developed further. The resulting distribution could be cooled quickly and coalesced into a single bunch to optimize the luminosity of a muon collider. After a brief elaboration of the QIHC concept, some recent developments are described.

• M. Popovic, A. Moretti
  Fermilab, Batavia
• C.M. Ankenbrandt, M.A.C. Cummings, R.P. Johnson, M.L. Neubauer
  Muons, Inc, Batavia

Alternative RF cavity fabrication techniques for accelerator applications at low frequencies are needed to improve manufacturability, reliability and cost. RF cavities below 800 MHz are large, take a lot of transverse space, increase the cost of installation, are difficult to manufacture, require significant lead times, and are expensive. Novel RF cavities partially loaded with a ceramic for accelerator applications will allow smaller diameter cavities to be designed and built. The manufacturing techniques for partially loaded cavities will be explored. A new 200MHz cavity will be built for the Fermilab Proton Source to improve the longitudinal emittance and energy stability of the linac beam at injection to the Booster. A cavity designed for 400 MHz with a ceramic cylinder will be tested at low power at cryogenic temperatures to test the change in Qo due to the alumina ceramic. Techniques will be explored to determine if it is feasible to change the cavity frequency by replacing an annular ceramic insert without adversely effecting high power cavity performance.

• G. Flanagan, R.J. Abrams, C.M. Ankenbrandt, M.A.C. Cummings, R.P. Johnson
  Muons, Inc, Batavia
• M. Popovic
  Fermilab, Batavia

The designs of accelerator systems that will be needed to transform Fermilab's Project X into a high-power proton driver for a muon collider and/or a neutrino factory are discussed. These applications require several megawatts of beam power delivered in tens or hundreds of short multi-GeV bunches per second, respectively. Project X may require a linac extension to higher energy for this purpose. Other major subsystems that are likely to be needed include storage rings to accumulate and shorten the proton bunches and an external beam combiner to deliver multiple bunches simultaneously to the pion production target.