THE UEA POSITRON REEMISSION MICROSCOPE - FIRST IMAGES

Images have been recorded using the laboratory-based positron re-emiss ion microscope constructed at the: University of East Anglia (UEA). Th e microscope has been designed to operate in reflection geometry with the view to studying the surface characteristics of 'real', thick samp les, without extensive preparation procedures. The first, deliberately low-magnification, images are of an annealed, electroformed nickel me sh (linewidth 10 mu m, spacing 40 mu m) placed over a well-annealed po lycrystalline tungsten foil, both before and after annealing the nicke l mesh, The false-colour images indicate (a) a magnification of about 80 x, as expected from the objective lens used, (b) a resolution of ab out 10 mu m, (c) contrast between surfaces with different positron wor k functions. Image signal rates of about 45 s(-1) were recorded. Plans to improve the magnification/resolution of the system are discussed.