  The Muon Ionization Cooling Experiment (MICE) at the Rutherford Appleton
Laboratory aims to demonstrate $\approx$ 10% ionization cooling of a muon beam
by its interaction with low-Z absorber materials followed by restoration of
longitudinal momentum in RF linacs. MICE Step IV, including the first LH2 or
LiH absorber cell sandwiched between two particle tracking spectrometers, is
the collaboration's near-term goal. Two large superconducting spectrometer
solenoids and one focus coil solenoid will provide a magnetic field of
$\approx$4 T in the tracker and absorber-cell volumes. The status of these
components is described, as well as progress towards Steps V and VI, including
the eight RF cavities to provide the required 8 MV/m gradient in a strong
magnetic field; this entails an RF drive system to deliver 2 MW, 1 ms pulses of
201 MHz frequency at 1 Hz repetition rate, the distribution network to deliver
1 MW to each cavity with correct RF phasing, diagnostics to determine the
gradient and the muon transit phase, and development of the large-diameter
magnets required for the linacs.
