FIGURE 7.1

Schematic and aerial view of CEBAF at the Thomas Jefferson National Accelerator Facility (TJNAF) in Newport News, Virginia. The accelerator is based on superconducting cavities for acceleration. Beams are recirculated and accelerated up to 5 times to provide intense continuous electron beams of 1-5 GeV, polarized and unpolarized, to three target areas simultaneously. The photo insert shows assembly of a superconducting cavity section in the clean room. (Courtesy TJNAF.)

Accelerator Center (SLAC), and continue to be involved in measurements at Fermilab and other high-energy facilities around the world.

Two current key objectives of nuclear physics, understanding the quark structure of nucleons and nuclei and the search for the quark-gluon plasma, have demanded higher energies, beam currents, and duty factors for electrons, and much higher energies for heavy ions. This motivated the construction of two large facilities designed specifically for nuclear physics at these research frontiers: CEBAF at the Thomas Jefferson National Accelerator Facility (TJNAF) in Virginia (shown in Figure 7.1), a high-current, continuous-beam electron accelerator of moderately high energy that has recently become operational; and the