Semi-elastic impact studies of carbonyl iron microspheres on diamond-polished metal targets (relevant to interelectrode bouncing of charged microparticles in a high-voltage vacuum gap)

Abstract

A UHV microparticle gun has been used to accelerate carbonyl iron spheres of diameters ranging from 0.1 to 2 mu m to velocities of 20-100 m s^-1 for semi-elastic impact studies on ¹/₄ mu m diamond polished metal electrodes. The mean values of the microscopic coefficients of restitution have been measured for a range of target materials of varying hardness (lead, copper, nickel, phosphor bronze, iron, titanium, stainless steel and carbon), and are in broad agreement with the previously determined macroscopic behaviour. The considerable scatter associated with the present experimental results has been interpreted in terms of the microtopography of the target surfaces.