Ionography imaging chamber

Claim 2

In an imaging chamber for an x-ray system, the improvement comprising: first and second substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; means for connecting a power supply across said electrodes; and means for maintaining along the gap surfaces of said electrodes, electrostatic potentials corresponding to the electrostatic potentials for concentric spherical metal electrodes so that the electric field lines in said gap converge substantially to a point.

Claim 3

An imaging chamber as defined in claim 1 wherein said first and second electrodes are of low conductivity material, with said means for connecting including circuit means for connecting the power supply to the center of said first electrode and to opposite edges of said second electrode, and with said means for maintaining including a resistance connected between opposite edges of said first electrode and the center of said second electrode completing a current path across the power supply to produce an electrostatic field in the gap, with the conductivity per unit area of each of said electrodes varying from a central zone to said edges such that the electrostatic potential at the gap surfaces of the electrodes is the same as the electrostatic potential for concentric spherical metal electrodes.

Claim 4

In an imaging chamber for an x-ray system, the improvement comprising: first and second substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; means for connecting a power supply across said electrodes; and means for maintaining along the gap surfaces of said electrodes, electrostatic potentials corresponding to the electrostatic potentials for concentric spherical metal electrodes, with the electrostatic potentials theta 1 and theta 2 at the gap surfaces of the electrodes substantially theta 1 (p1) VgD/d(1+x12/D2) 1/2 theta 2 (p2) VgD''/d (1+x22/D''2) 1/2 where p is the position on the electrode gap surface, Vg is the voltage drop across the gap at the gap center, D is the distance from one electrode gap surface to the x-ray source, d is the distance between electrode gap surfaces, D'' D+d, and x is the distance of p from the gap center in polar coordiNates for flat electrodes and is the axial distance of p from the gap center for cylindrical electrodes.

Claim 5

In an imaging chamber for an x-ray system, the improvement comprising: first and second substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; means for connecting a power supply across said electrodes; and means for maintaining along the gap surfaces of said electrodes, electrostatic potentials corresponding to the electrostatic potentials for concentric spherical metal electrodes, with the electrostatic potentials theta 1 and theta 2 at the gap surfaces of the electrodes substantially theta 1 (p1) VgD/d(1+x12/D2) 1/2 theta 2 (p2) VgD''/d (1+x22/D''2) 1/2 where p is the position on the electrode gap surface, Vg is the voltage drop across the gap at the gap center, D is the distance from one electrode gap surface to the x-ray source, d is the distance between electrode gap surfaces, D'' D+d, and x is the distance of p from the gap center in polar coordiNates for flat electrodes and is the axial distance of p from the gap center for cylindrical electrodes.

Claim 6

In an imaging chamber for an x-ray system, the improvement comprising: first and second substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; means for connecting a power supply across said electrodes; and means for maintaining along the gap surfaces of said electrodes, electrostatic potentials corresponding to the electrostatic potentials for concentric spherical metal electrodes, with each of said first and second electrodes comprising a plurality of sections of low conductivity material, with each section of different and substantially uniform conductivity, with said means for connecting including circuit means for connecting the power supply to the center of said first electrode and to opposite edges of said second electrode, and with said means for maintaining including a resistance connected between opposite edges of said first electrode and the center of said second electrode completing a current path across the power supply to produce an electrostatic field in the gap, with the conductivity per unit area of each section of said electrodes varying from a central zone to said edges such that the electrostatic potential at the ggap surfaces of the electrodes corresponds stepwise to the electrostatic potential for concentric spherical metal electrodes.

Claim 7

In an imaging chamber for an x-ray system, the improvement comprising: first and second substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; means for connecting a power supply across said electrodes; and means for maintaining along the gap surfaces of said electrodes, electrostatic potentials corresponding to the electrostatic potentials for concentric spherical metal electrodes, with each of said first and second electrodes comprising a plurality of sections of low conductivity material, with each section of different and substantially uniform conductivity, with said means for connecting including circuit means for connecting the power supply to the center of said first electrode and to opposite edges of said second electrode, and with said means for maintaining including a resistance connected between opposite edges of said first electrode and the center of said second electrode completing a current path across the power supply to produce an electrostatic field in the gap, with the conductivity per unit area of each section of said electrodes varying from a central zone to said edges such that the electrostatic potential at the ggap surfaces of the electrodes corresponds stepwise to the electrostatic potential for concentric spherical metal electrodes.

Claim 8

An imaging chamber as defined in claim 1 wherein said electrodes have flat parallel gap surfaces and a central disk of high conductivity material.

Claim 9

An imaging chamber as defined in claim 1 wherein said electrodes have concentric cylindrical gap surfaces and a central arcuate strip of high conductivity material.

Claim 10

In an imaging chamber for an x-ray system, the improvement comprising: first and second substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; means for connecting a power supply across said electrodes; and means for maintaining along the gap surfaces of said electrodes, electrostatic potentials corresponding to the electrostatic potentials for concentric spherical metal electrodes, with said electrodes of metal, and with said means for maintaining including first and second dielectric sheets, each of uniform thickness, with said first sheet at said first electrode and said second sheet at said second electrode defining a gap between the sheets, each of said sheets having a dielectric constant varying across the sheet such that the electrostatic potential at the gap surfaces is the same as the electrostatic potential for concentric spherical metal electrodes.

Claim 11

In an imaging chamber for an x-ray system, the improvement comprising: first and second substantially planar electrodes; means for mounting said electrodes in the chamber in spaced relation defining a gap therebetween; means for connecting a power supply across said electrodes; and means for maintaining along the gap surfaces of said electrodes, electrostatic potentials corresponding to the electrostatic potentials for concentric spherical metal electrodes, with said electrodes of metal, and with said means for maintaining including first and second dielectric sheets, each of uniform thickness, with said first sheet at said first electrode and said second sheet at said second electrode defining a gap between the sheets, each of said sheets having a dielectric constant varying across the sheet such that the electrostatic potential at the gap surfaces is the same as the electrostatic potential for concentric spherical metal electrodes.

Claim 12

A system as defined in claim 7 wherein each of said sheets comprises a first layer of a first dielectric constant and a second layer of a second dielectric constant, with one of said layers having a maximum thickness at the center thereof and tapering to a minimum thickness at the edges thereof, and with the other of said layers having a complementary thickness.

Claim 13

In an imaging chamber for an x-ray system, the improvement comprising: first and second substantially planar electrodes of low conductivity material; means for mounting said electrodes in the chamber in spaced relation defining a gap there between; means for connecting a power supply to the center of said first electrode and to opposite edges of said second electrode; and a resistance connected between opposite edges of said first electrode and the center of said second electrode completing a current path across the power supply to produce an electrostatic field in the gap; with the conductivity per unit area of each of said electrodes varying from a central zone to said edges such that the electrostatic potential at the gap surfaces of the electrodes is the same as the electrostatic potential for concentRic spherical metal electrodes.

Claim 14

In an imaging chamber for an x-ray system, the improvement comprising: first and second substantially planar electrodes of low conductivity material; means for mounting said electrodes in the chamber in spaced relation defining a gap there between; means for connecting a power supply to the center of said first electrode and to opposite edges of said second electrode; and a resistance connected between opposite edges of said first electrode and the center of said second electrode completing a current path across the power supply to produce an electrostatic field in the gap; with the conductivity per unit area of each of said electrodes varying from a central zone to said edges such that the electrostatic potential at the gap surfaces of the electrodes is the same as the electrostatic potential for concentRic spherical metal electrodes.

Claim 15

An imaging chamber as defined in claim 9 wherein the variation in conductivity per unit area is obtained by varying the thickness of the electrode from the central zone to said edges.

Claim 16

An imaging chamber as defined in claim 9 wherein the variation in conductivity per unit area is obtained by varying the conductivity of the material of the electrode from the central zone to said edges.

Claim 17

An imaging chamber as defined in claim 9 wherein the variation in conductivity per unit area is obtained by varying both the thickness of the electrode and the conductivity of the material of the electrode from the central zone to said edges.

Claim 18

An imaging chamber as defined in claim 9 wherein the electrostatic potentials theta 1 and theta 2 at the gap surfaces of the electrodes are theta 1 (p1) Vg D/d (1+x12/D2) 1/2 theta 2 (p2) Vg D''/d (1+x22/D''2) 1/2 where p is the position on the electrode gap surface, Vg is the voltage drop across the gap at the gap center, D is the distance from one electrode gap surface to the x-ray source, d is the distance between electrode gap surfaces, D'' D+d, and x is the distance of p from the gap center in polar coordinates for flat electrodes and is the axial distance of p from the gap center for cylindrical electrodes.

Claim 19

An imaging chamber as defined in claim 9 wherein said electrodes have flat parallel gap surfaces and a central disk of high conductivity material.

Claim 20

An imaging chamber as defined in claim 9 wherein said electrodes have concentric cylindrical gap surfaces and a central arcuate strip of high conductivity material.