The SAL Facility

The Saskatchewan Accelerator Laboratory has been delivering high duty factor tagged bremsstrahlung beams up to 280 MeV since 1989. These have been used for studies of the proton and light nuclei by several US groups, notably from the Universities of Illinois, Boston, and Washington, and from Los Alamos National Lab. Significant contributions have been made in the determination of the electric and magnetic polarizabilities of the proton, providing an important new test of low- energy QCD through the calculational techniques of Chiral Perturbation Theory (PT).

A significant effort is now being mounted to measure photo- production in the threshold region. Interest in such experiments has been heightened by recent PT calculations of threshold p-wave multipoles which seem to be rapidly converging, thus providing a more definitive test than their s-wave counterparts. Here, the most striking experimental signatures are expected in the polarized photon asymmetry. The SAL group is working on the development of linearly polarized photon beams from off-axis and coherent bremsstrahlung, as well as on a Pb-glass detector array (IGLOO) that has been optimized for this work. These measurements are projected to begin in 1997. In the long-term, the future of SAL as a facility for electromagnetic nuclear physics is coupled to their recent proposal to construct a Synchrotron Light Source for material science. If funded (post-1997), this could have a potentially negative impact on their nuclear programs because of the necessary commitment of the SAL staff to the construction project.