Kinetics of adsorption and photodesorption of hydrogen on copper surfaces

The kinetics of adsorption and photodesorption of hydrogen on a Cu surface is discussed for the next generation of high energy proton colliders. The equilibrium solution of a rate equation describing the surface kinetics leads to an expression for the gas pressure, which we estimate to be about 10-8Torr for proton beam colliders like the now defunct 20-TeV superconducting super collider. Using classical molecular dynamics simulations with reliable interatomic potentials we find the fractional energy loss of hydrogen on Cu(100), for incident energies ranging from 0.1 endash 1.0 eV, to be between 1%endash 6%. This leads to an estimate of 10-4s for the average lifetime of the hydrogen molecule in the beam tube. copyright 1997 American Vacuum Society