Surface roughness realized and evaluated in different dimensional range and its effect on field emission behavior

The effect of the surface roughness in different dimensional range on the field emission behavior of CuCr electrodes is studied. Hawking machining and finish machining are used to achieve the different surface conditions. The macroscopic surface roughness value of the hawking machining, measured by the conventional roughness meter, is one order of magnitude lower than that of the finishing machining. However, the obvious increase of field emission tendency was found on the electrode surface obtained by the hawking machining compared with the finishing machining. The surface roughness in nanoscale was evaluated by AFM (Atomic Force Microscope), indicating that the micro-roughness of the hawking machining is higher than that of the finishing machining. These results indicated the deficiency of the conventional roughness evaluation method on the field emission tendency and suggested that hawking machining might not improve endurance voltage strength of the electrodes in vacuum.