This grant supports an upgrade of the Princeton University Cyclotron Laboratory. The upgrade consists primarily of state- of-the-art instrumentation and equipment for nuclear physics research. The equipment will include a dilution refrigerator to facilitate development of bolometer detectors, an alexandrite laser for a polarized target system, an improved atomic beams facility, associated beam lines, and upgrades to the laboratory computer system. Funds also are included for the replacement of obsolete components of the accelerator systems, to reduce accelerator down time and to permit operation with increased beam intensity, stability and energy resolution. The equipment will be used by faculty and students to investigate a variety of issues in fundamental physics, such as time reversal invariance and parity non-conservation in weak interaction processes in nuclei, research in nuclear astrophysics, and studies of nuclear reactions and structure.