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

In the last 20 years, superconducting RF (SRF) cavities have been developed to the point that a CW SRF linac is the best candidate driver for subcritical reactors. We discuss how one appropriately designed 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. Such a station will generate no greenhouse gases, produce minimal nuclear waste and no byproducts that are useful to rogue nations or terrorists, incinerate waste from conventional nuclear reactors, and efficiently use abundant thorium fuel that does not need enrichment. 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.

• E.S.M. McCrory, F.G. Garcia, T.K. Kroc, A. Moretti, M. Popovic
  Fermilab, Batavia

We have been collecting data on the conditioning of the high-gradient accelerating cavities in the Fermilab 400 MeV H-Minus Linac for over 16 years [1]. This linac was upgraded in 1989 from a 201 MHz Alverez structure to include 805 MHz side-coupled cavities. Automated measurements of the sparking rate have been recorded since 1994 and are reported here. The sparking rate has declined since the beginning, but there are indications that this rate may have leveled off now. The X-rays emitted by the cavities are continuing to decrease.

[1] Kroc, et al., Proceedings of LINAC96, pp 338-340

• M. Popovic
  Fermilab, Batavia
• L. Coney
  UCR, Riverside, California
• P.M. Hanlet
  IIT, Chicago, Illinois
• D.M. Kaplan
  Illinois Institute of Technology, Chicago, Illinois

Muon ionization cooling provides the only practical solution to prepare high brilliance beams necessary for a neutrino factory or muon colliders. The muon ionization cooling experiment (MICE) is thus a strategic R&D project for neutrino physics. It is under development at the Rutherford Appleton Laboratory (UK). It comprises a dedicated beam line to generate a range of input emittance and momentum, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. A first measurement of emittance is performed in the upstream magnetic spectrometer with a scintillating fiber tracker. A cooling cell will then follow, alternating energy loss in liquid hydrogen and RF acceleration. A second spectrometer identical to the first one and a particle identification system provide a measurement of the outgoing emittance. In the 2010 run, completed in August, the beam and most detectors have been fully commissioned. The time of the first measurement of input beam emittance is closely approaching. The plan of steps of measurements of emittance and emittance reduction (cooling), that will follow in 2011 and later, will be reported.

I submit this as chair of the MICE speakers bureau. If accepted, I will find a member of the collaboration that will register to the conference and present the contribution.

• S. Nagaitsev, M. Popovic, G.V. Romanov, R.C. Webber, V.P. Yakovlev
  Fermilab, Batavia
• Q. Ji, D. Li, T. Schenkel, J.W. Staples, S.P. Virostek
  LBNL, Berkeley, California

A multi-MW proton facility, Project X has been proposed and currently under development at Fermilab. Project X is critical for future development of accelerator complex for future high energy physics programs in the US. In collaboration with Fermilab, LBNL is actively involved in the development and design studies of the front-end system for Project X. The front-end system would consist of H^- ion source(s), low-energy beam transport (LEBT), normal conducting CW Radio-Frequency-Quadrupole (RFQ) accelerator(s), medium-energy beam transport (MEBT), beam chopper(s) and normal conducting CW rebuncher cavities. We will review and present R&D programs and recent study progress on the front-end system of Project X. These studies may include beam dynamics simulations and concepts for LEBT, RFQ, MEBT and narrow band chopper, and preliminary conceptual designs of normal conducting CW RFQ(s) and rebuncher cavities.

• M. Popovic, A. Moretti
  Fermilab, Batavia
• A. Dudas, R.P. Johnson, M.L. Neubauer, R. Sah
  Muons, Inc, Batavia

Magnetrons are the lowest cost microwave source in dollars/kW, and they have the highest efficiency (typically greater than 85%). However, the frequency stability and phase stability of magnetrons are not adequate when used as power sources for accelerators. Novel variable frequency cavity techniques have been developed to phase and frequency lock the magnetrons, allowing their use for either individual cavities, or cavity strings. Ferrite or YIG (Yttrium Iron Garnet) materials are placed in the regions of high magnetic field of radial-vaned, π−mode structures of a selected ordinary magnetron. A variable external magnetic field that is orthogonal to the magnetic RF field of the magnetron surrounds the magnetron to vary the permeability of the ferrite or YIG material. Measurements of a prototype magnetron will be described.