Performance of Litton 805 MHz, 12 MW klystrons

The Fermilab Linac Upgrade will increase the energy of the H ^{linac from 201 to 401.5 MeV. This will be achieved by replacing the last four 201.24 MHz drift-tube linac cavities with seven 805 MHz side-coupled cavity modules. Each accelerator module will be powered with a 12 MW klystron-based power supply. The purpose of this report is to present a body of representative data for the klystron tubes at various conditions and to detail the procedures used}