A plasma system for changing a microscopy material sample comprises a microscopy material sample holder for holding a microscopy material sample in place in a desired orientation, and a receptacle holder for receiving the sample holder and an RF antenna. The microscopy sample is positioned relative to the antenna so that no point on the antenna is in direct line-of-sight contact with the microscopy sample. This feature of avoiding direct line-of-sight contact between the antenna and the sample assists in preventing, or at least minimizing, ion sputtering of system component material onto the specimen or sample 10 that is being trimmed. Moreover, portions of the system which are in direct line-of-sight contact with the sample are comprised of material having a low sputtering yield, preferably carbon. The material may comprise graphite, and may be in the form of a carbon coating or a carbon paint.