  The Muon Ionization Cooling Experiment (MICE) has been built at the STFC
Rutherford Appleton Laboratory to demonstrate the principle of muon beam
phase-space reduction via ionization cooling. Muon beam cooling will be
required at a future proton-derived neutrino factory or muon collider.
Ionization cooling is achieved by passing the beam through an energy-absorbing
material, such as liquid hydrogen, and then re-accelerating the beam using RF
cavities. This paper describes the hydrogen system constructed for MICE
including: the liquid-hydrogen absorber, its associated cryogenic and gas
systems, the control and monitoring system, and the necessary safety
engineering. The performance of the system in cool-down, liquefaction, and
stable operation is also presented.
