Calibration of volume charge measurements by use of electron beam implantation

The authors consider the use of charges implanted by means of energetic electron beams to create known charge distributions for calibration purposes. For a successful calibration the reference charge samples should provide a well-defined charge, including location, distribution, and magnitude (and sign). Although these parts of the calibration may be accomplished with different samples, it is preferable for simplicity and accuracy to include these in a single sample. The e-beam implanted charge distributions have been found to achieve the needed reference charge characteristics. Specifically, it was demonstrated that e-beam implantation of charges in charge-retaining plastics, such as PMMA (polymethyl methacrylate), provides a useful reference for the purpose of calibrating charge measurement instruments