NBS-SURF II: A Small, Versatile Synchrotron Light Source

Synchrotron radiation sources do not have to be large multi-megadollar installations. SURF II is based on a compact electron storage ring with a radius of only 0.84 m, an operating energy of 250 MeV, and useful light output down to 5 nm. Small beam size, high brightness and wide-angle light ports give SURF II unique capabilities. Presently five beamlines are instrumented and operational, supporting experiments in atomic and molecular physics, surface science and materials studies, as well as providing optical calibration services. Nearing completion is a large facility for calibrating optical instruments, especially those intended for space flight. The capability of determining the absolute light flux emitted by SURF II has recently been improved and is now operational. The technique employs ultralinear silicon photodiodes to detect and count individual electrons in the stored beam. Other user conveniences include close access to the machine, flexible scheduling and close interaction with the operations staff. The machine's simplicity contributes to reliability and a high ratio of beamtime to down-time.