APT high energy linac intertank assembly design

The 700-MHz superconducting high energy (HE) linac in the Accelerator for the Production of Tritium (APT) accelerates a 100 mA continuous wave (cw) proton beam from 211 MeV to a final energy of up to 1.79 GeV. The design of the 700 MHz radio frequency (RF) cavities has been optimized for two beam velocity intervals, β=0.64 and β=0.82. Two intertank designs, medium-β and high-β, have been developed for these two velocity intervals. Three cryomodule designs have been developed corresponding to three different lattice periods in the APT HE Linac. Room temperature quadrupole doublet magnets placed in the intertank assemblies between the cryomodules focus the beam. Each quadrupole magnet contains additional dipole steering windings to correct for small beam misalignments. The intertank assembly between cryomodules also includes beam diagnostic instrumentation, the interconnecting beam pipe, flanges, and the vacuum interface. This paper presents the physics parameters, the results of 3-D magnetic field calculations, and the detailed design of the quadrupoles and the associated intertank assemblies for the medium-β and high-β sections of the HE Linac