Patent Number: 
Section: claims

1. A method of operating an ion implanter comprising:producing an ion beam;receiving ions from the ion beam in a component having an entrance opening, an internal surface for absorbing ions that have passed through the entrance opening an array of electrodes comprising a first array of upstream electrodes disposed adjacent the entrance opening and a second array of downstream electrodes disposed between the first array and the internal surface, said electrodes being generally planar and positioned such that the side edges thereof face the entrance opening and provide a line of sight to an internal surface, wherein the component is arranged to receive ions from an ion beam through the entrance opening such that ions strike the internal surface; andproviding an electrical bias on elements of the component. 2. The method of claim 1, further comprising providing a further electrical bias to one or more electrodes located adjacent the internal surface of the component such that the one or more electrodes repel electrons ejected from the internal surface. 3. The method of claim 1, further comprising providing a further electrical bias to one or more electrodes located adjacent the entrance opening so as to be at substantially the same potential as the ion beam as it passes the component. 4. An ion implanter comprisingan ion-receiving component which defines an internal surface, an entrance opening, and an array of electrodes comprising a first array of upstream electrodes disposed adjacent the entrance opening and a second array of downstream electrodes disposed between the first array and the internal surface, said electrodes being generally planar and positioned such that the side edges thereof face the entrance opening and provide a line of sight to an internal surface, wherein the component is arranged to receive ions from an ion beam through the entrance opening such that ions strike the internal surface, anda power supply apparatus for providing an electrical bias to elements of the ion-receiving component. 5. The ion implanter of claim 4, wherein the power supply apparatus operates to bias the internal surface to be at substantially the same potential as the ion beam. 6. The ion implanter of claim 4, wherein the power supply apparatus operates to bias one or more upstream electrodes to be at substantially the same potential as the ion beam. 7. The ion implanter of claim 4, wherein the power supply apparatus operates to bias one or more downstream electrodes to repel electrons liberated from the internal surface. 8. The ion implanter of claim 4, wherein the power supply operates to bias the first array of upstream electrodes to be at substantially the same potential as the ion beam and to bias the second array of downstream electrodes to repel electrons liberated from the internal surface. 9. The ion implanter of claim 4, wherein the component is a beam dump or a beam stop.