Comment on "Using the /spl lambda/ function to evaluate probe measurements of charged dielectric surfaces" [with reply]

For original paper, see T.O. Rerup et al., ibid., vol. 3, pp. 770-777 (1996). Rerup et al. described the calibration of electrostatic probes used to measure the surface charge on dielectrics. This work showed that the use of the probe response theorem (the /spl lambda/ function), rather than the simple capacitative formula, leads to better experimental values. In this discussion, the commenter wishes to show that a more detailed interpretation can be extracted from the numerical results. In reply, Rerup et al. demonstrate that simple statistics cannot be used to extract, in a conclusive manner, a more detailed interpretation of the /spl sigma//sub /spl lambda//,/spl sigma//sub D/ patterns. Moreover, with the limitations imposed by the axially symmetric /spl lambda/ function, there is little to be gained in pursuing the source of the discrepancies between /spl sigma//sub /spl lambda// and /spl sigma//sub F/. They agree with the commenter that a multi-point scanning procedure would be essential if the functional form of the surface charge distribution were unknown.