Field ion microscopic observation of interaction phenomena of neon atoms with platinum and platinum-gold alloy surfaces

Abstract Platinum and platinum-gold alloys have been imaged in a field ion microscope with helium at low pressures between 10 −6 and 10 −4 Torr using a channel plate multiplier to intensify the brightness of the picture. Under these conditions hopping bright spots on lattice sites of fully resolved netplanes can be observed. To investigate this phenomenon in more detail a 16 mm movie camera with a speed up to 28 pictures per second has been used. Since the number of bright spots is dependent on the partial pressure of neon this effect may be attributed to adsorption of neon on the platinum surface. The bright spots appearing in the normal imaging mode without additional neon introduced into the system are due to the neon being present yet in high purity helium (approximately 3 ppm).