X-ray tube electron sources
First Claim
1. An electron source for an X-ray scanner comprising:
- at least one electron emitter in a first plane;
a plurality of extraction elements in a second plane, wherein the first plane and second plane are substantially parallel and separated by a contiguous space, wherein said extraction elements are substantially perpendicular to the at least one electron emitter, and wherein a space between two adjacent extraction elements and said at least one electron emitter define a source region;
a plurality of elongate focusing elements in a third plane, wherein the third plane and second plane are substantially parallel and separated by a contiguous space defining a second region and wherein said focusing elements focus beams of electrons after they have passed the extraction elements; and
a controller that applies an electrical potential to certain of said plurality of extraction elements wherein said application of the electrical potential causes electrons to be moved from a first source region to the second region.
1 Assignment
0 Petitions
Accused Products
Abstract
An X-ray tube includes an emitter wire (18) enclosed in a suppressor(14, 16). An extraction grid comprises a number of parallel wires (20) extending perpendicular to the emitter wire, and a focusing grid comprises a number of wires (22) parallel to the grid wires (20) and spaced apart at equal spacing to the grid wires (20). The grid wire are connected by means of switches to a positive extracting potential or a negative inhibiting potential, and the switches are controlled so that at any one time a pair of adjacent grid wires (22) are connected together to form an extracting pair, which produce an electron beam. The position of the beam is moved by switching different pairs of grid wires to the extracting potential.
-
Citations
37 Claims
-
1. An electron source for an X-ray scanner comprising:
-
at least one electron emitter in a first plane; a plurality of extraction elements in a second plane, wherein the first plane and second plane are substantially parallel and separated by a contiguous space, wherein said extraction elements are substantially perpendicular to the at least one electron emitter, and wherein a space between two adjacent extraction elements and said at least one electron emitter define a source region; a plurality of elongate focusing elements in a third plane, wherein the third plane and second plane are substantially parallel and separated by a contiguous space defining a second region and wherein said focusing elements focus beams of electrons after they have passed the extraction elements; and a controller that applies an electrical potential to certain of said plurality of extraction elements wherein said application of the electrical potential causes electrons to be moved from a first source region to the second region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
-
Specification