Patent Number: 046577220
Section: claims

1. An ion accelerating device comprising: a cathode,  an anode,  said anode comprising tubular conducting means having its centerline along the centerline of the beam,  a target,  means for accelerating a beam of electrons from the cathode through the anode to the target, including means for placing a potential difference between the cathode and the anode,  means for supplying ions to the beam so that the ions are accelerated toward the target,  the improvement wherein:  the target being positioned across the end of the tubular anode that is farthest from the cathode,  a return path for the electrons reaching the target for conducting the electrons that reach the target,  said anode comprising means for forming a potential trough that collects and accelerates ions toward the target.  said tubular conducting means has a diameter that increases along at least a limited portion thereof adjacent the end thereof closest to the cathode.  said tubular conducting means includes a dielectric sleeve surrounding said tubular conducting means, and a bulkhead around said sleeve,  said sleeve preventing said bulkhead from shorting said tubular conducting means.  a limited portion adjacent that end of said tubular conductive means that is closest to the cathode being composed of graphite, so that a spark-over to the anode will not be a sustained one.  providing a cathode spaced from said anode,  establishing a beam of electrons that leaves said cathode and enters said tubular anode and then passes through said tubular anode to the target,  positioning the target adjacent the end of the anode that is farthest from the cathode,  providing a return path for the electrons reaching the target,  adding ions to the beam,  forming a potential trough in said beam to move ions toward the target, and  intensifying said potential trough while the beam is traveling in said anode and toward the target,  whereby to collect and move at least some of said ions towards the target. 2. An ion accelerating device as defined in claim 1 in which the tubular conducting means is made of material resistive to flow of electrons and the cross-section of the tubular conducting means being sufficiently small so that the tubular conductive means will intercept some electrons that have strayed from the beam and so that the flow of such electrons along the tubular conductive means will sustain an electrical field. 3. An ion accelerating device as defined in claim 2 in which: 4. An ion accelerating device as defined in claim 2 in which said limited portion flares outwardly as it approaches said end thereof closest to the cathode, said tubular conductive means being composed of material resistive to the electrical current so that there will be a potential drop across it and so that an electric field will be created that accelerates the beam. 5. An ion accelerating device as defined in claim 4 in which: 6. An ion accelerating device as defined in claim 2 comprising: 7. The method of accelerating ions through a tubular anode to a target comprising: 8. The method of claim 7 in which said anode has an electric field which intensifies said potential trough and collects and moves at least some of said ions towards the target. 9. The method of claim 8 in which said anode has high resistivity and has a current flowing along the same whereby said anode has said electric field. 10. The method of claim 7 comprising providing substantial electrical resistivity for the anode, and conducting an electric current along said anode whereby said anode has an electric field that intensifies said potential trough. 11. The method of claim 10 in which said electric field is maintained in intensity along the path starting at the end of the anode farthest from the target and extending to the end of the anode closest to the target.