A SCANNING PHOTOELECTRON MICROSCOPE (SPEM) AT THE NSLS

We are in the process of developing and commissioning a scanning photoelectron microscopy (SPEM) at the X1A beamline of the National Synchrotron Light Source (NSLS). It is desigend to make use of the Soft X-ray Undulator (SXU) at the NSLS. This high brightness source illuminates a Fresnel zone plate, which forms a focused probe, leq;;0.2 µm in size, on the specimen surface. A grating monochromator selects the photon energy in the 400-800 eV range with an energy resolution of better than 1 eV. The expected flux in the focus is in the 5 × 107-109 photons/s range. A single pass Cylindrical Mirror Analyzer (CMA) is used to record photoemission spectra, or to form an image within a fixed electron energy bandwidth as the specimen is mechanically scanned. As a first test, a 1000 mesh Au grid was successfully imaged with a resolution of about 1 µm and the CMA tuned to the Au 4f photoelectron peak. Once it is commissioned, a program is planned which will utilize the microscope to study beam sensitive systems, such as thin oxide/sub-oxide films of alumina and silica, and ultimately various adsorbates on these films. © 1990 IOP Publishing Ltd.