Performance of new infrared beamline U12IR at the National Synchrotron Light Source

The instrumentation and performance of the new infrared beamline U12IR at t he National Synchrotron Light Source of Brookhaven National Laboratory is d escribed. This beamline utilizes infrared synchrotron radiation from a bend ing magnet. A combination of beamline design features and spectroscopic ins trumentation allows the facility to reach the extremely low frequency limit of similar to 2 cm(-1) (i.e., 60 GHz or a photon energy of 250 mu eV). The infrared light from the synchrotron emission at U12IR is compared to stand ard thermal sources and reveals substantial benefits for the study of small samples. In particular, the intensity of the synchrotron radiation in the far infrared can be as much as 200 times greater than that from a blackbody when millimeter-sized samples are measured. The effects of diffraction and noise on beamline performance are also discussed. (C) 1999 American Instit ute of Physics. [S0034-6748(99)02407-7].