A four cell lattice for the UCLA compact light source synchrotron

The 1.5 GeV compact light source UCS proposed for UCLA must fit into a shielded vault that is 9.144 meters (30 feet) wide. In order for the machine fit into the into the allowable space, the ring circumference must be reduced 36 meters, the circumference of the six cell lattice, to something like 26 or 27 meters. The four cell lattice described in this report has a ring circumference of 27.0 meters. The four cell ring consists of twelve 6.5 T superconducting dipoles, twenty-four conventional quadrupoles, sixteen conventional sextupoles and four straight sections 1.02 meters long. The 1.5 GeV electron beam is bend in the dipoles to produce X-rays with a critical energy of 9.8 keV. The superconducting dipoles have been modeled in three dimensions. The 3-D modeling shows that magnetic induction falls off from its full design value to nearly zero in about 50 mm at the ends of the dipoles. The magnetic length of the dipole is calculated to be 403 mm.