AN ULTRAHIGH-VACUUM (UHV) APPARATUS TO STUDY THE INTERACTION BETWEEN ADSORBATES AND PHOTONS

An UHV apparatus has been designed and constructed for studying the in teraction between adsorbates and photons. Since a variety of light sou rces and experimental geometries are used in these studies, the system was designed to be as flexible as possible. The system is put on a si ngle frame so that it can be transported from one photon source to ano ther, A compact, exchangeable, high-pressure cell is designed to provi de easy access for photons to the crystal. To allow the study of small poly-atomics the following combination of detection techniques are in stalled: thermal desorption spectroscopy (TDS), x-ray photoelectron sp ectroscopy (XPS), Auger electron spectroscopy (AES), low-energy electr on diffraction (LEED) and reflection-adsorption infrared spectroscopy (RAIRS). Furthermore, a sample exchange system in combination with liq uid nitrogen sample cooling is incorporated. The exchange system allow s three samples to be stored in the main chamber. The sample exchange capability does not restrict the cooling capabilities-85 K within an h our after turning on the liquid nitrogen flow and 85 K within minutes after flashing to 800 K.