US3774029A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiographic system with xerographic printing
Assignee: ELSCINT IMAGING Inc
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Filing: 1972-06-12
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Granted: 1973-11-20
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Expires: 1992-06-12
Abstract
Abstract A system for making X-ray pictures by producing an electrostatic image on a dielectric sheet suitable for development by powder xerographic techniques. A pair of electrodes with a gas filled gap therebetween, with the dielectric sheet positioned at the anode or cathode and with the X rays directed past the object to the gas for producing electrons in the gap. An arrangement for increasing the quantity of electrons (or positive ions) moving toward the anode (or cathode) normal to the dielectric sheet and for providing high resolution images by enhancing the production of electrons in the gap and moderating the energy of the electrons, with superatmospheric high Z gas in the gap.
Inventors
- 👤 E Muntz
- 👤 A Proudian
- 👤 P Scott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:51
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/054; G03G15/0545
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
192 words
In a radiographic system for operation with a source of X rays, the combination of: a pair of electrodes comprising an anode and a cathode; first means for supporting said electrodes in spaced relation with a small gap therebetween and for maintaining a superatmospheric pressure in said gap; a dielectric sheet in said gap at one of said electrodes; an X-ray absorber and electron and positive ion emitter in said gap between said anode and cathode for producing a charge image on said dielectric sheet, said absorber and emitter comprising an X ray opaque gas at superatomspheric pressure and having an atomic number of at least 36; and second means for connecting a high voltage electric power supply across said electrodes for attracting electrons toward said anode and positive ions toward said cathode for deposit of one of said types of charged particles on said dielectric sheet; With the gas in the gap moderating the energy of and reducing the means free path of said electrons to increase the quantity of and reduce the dispersion of electrons moving toward said anode and positive ions toward said cathode normal to said dielectric sheet.
Claim 2
Dependent Claim
192 words
In a radiographic system for operation with a source of X rays, the combination of: a pair of electrodes comprising an anode and a cathode; first means for supporting said electrodes in spaced relation with a small gap therebetween and for maintaining a superatmospheric pressure in said gap; a dielectric sheet in said gap at one of said electrodes; an X-ray absorber and electron and positive ion emitter in said gap between said anode and cathode for producing a charge image on said dielectric sheet, said absorber and emitter comprising an X ray opaque gas at superatomspheric pressure and having an atomic number of at least 36; and second means for connecting a high voltage electric power supply across said electrodes for attracting electrons toward said anode and positive ions toward said cathode for deposit of one of said types of charged particles on said dielectric sheet; With the gas in the gap moderating the energy of and reducing the means free path of said electrons to increase the quantity of and reduce the dispersion of electrons moving toward said anode and positive ions toward said cathode normal to said dielectric sheet.
Claim 3
Dependent Claim
30 words
A system as defined in claim 1 in which said first means includes means for maintaining said gas in said gap at a pressure of at least about 150 psig.
Claim 4
Dependent Claim
35 words
A system as defined in claim 1 wherein the product of the gap width at the zone of X ray incidence times the gas pressure in the gap is at least about 10 mm atmospheres.
Claim 5
Dependent Claim
42 words
A system as defined in claim 1 wherein the product of the gap width at the zone of X ray incidence times the gas pressure in the gap is in the range of about 10 mm atmosphres to about 200 mm atmospheres.
Claim 6
Dependent Claim
47 words
A system as defined in claim 4 wherein the electric potential across said electrodes at the zone of X ray incidence is selected to provide operation in the plateau of the Townsend curve of voltage vs. current so that substantially no electron avalanching occurs in the gap.
Claim 7
Dependent Claim
47 words
A system as defined in claim 1 wherein the electric potential across said electrodes at the zone of X ray incidence is selected to provide operation in the plateua of the Townsend curve of voltage vs. current so that substantially no electron avalanching occurs in the gap.
Claim 8
Dependent Claim
21 words
A system as defined in claim 1 wherein said dielectric sheet is positioned at said anode and electrons are deposited thereon.
Claim 9
Dependent Claim
22 words
A system as defined in claim 1 wherein said dielectric sheet is positioned at said cathode and positive ions are deposited thereon.
Claim 10
Dependent Claim
33 words
A system as defined in claim 1 wherein said anode is a light metal or carbon readily penetrated by the X rays and is disposed on the X-ray source side of said gap.
Claim 11
Dependent Claim
33 words
A system as defined in claim 1 wherein said cathode is a light metal or carbon readily penetrated by the X rays and is disposed on the X-ray source side of said gap.
Claim 12
Dependent Claim
47 words
A system as defined in claim 1 including a control for the system high voltage electric power supply and for the X-ray source for simultaneously energizing the source to emit X-rays and energizing the system high voltage electric power supply to apply a voltage across said electrodes.
Claim 13
Dependent Claim
49 words
A system as defined in claim 11 wherein said system high voltage electric power supply provides a first lower voltage and a second higher voltage, with said control switching said system high voltage electric power supply from said first voltage to said second voltage on energizing the X-ray source.
Claim 14
Dependent Claim
62 words
A system as defined in claim 1 wherein said first means includes a pressure vessel with said electrodes disposed therein, said pressure vessel including means for installation and removal of said dielectric sheet to and from said one electrode, said pressure vessel including a curved thin wall readily penetrated by X rays and positionable on the X-ray source side of said electrodes.
Claim 15
Dependent Claim
26 words
A system as defined in claim 1 in which said second means includes means for maintaining the voltage across said electrodes at least about 1,000 volts.
Claim 16
Dependent Claim
30 words
A system as defined in claim 14 in which said first means includes means for maintaining said gas in said gap at a pressure of at least about 150 psig.
Claim 17
Independent Claim
157 words
A method of producing an electrostatic image on a dielectric sheet, including the steps of: positioning the dielectric sheet at an electrode in a gap between anode and cathode electrodes positioned adjacent an object to be imaged; passing x-rays through said object and one of said electrodes; absorbing incoming X rays in the gap by maintaining in the gap an X-ray opaque gas of atomic number at least 36 at superatomosperhic pressure and generating electrons and positive ions in the gas, and the gas in the gap moderating the energy of and reducing the mean free path of said electrons to increase the quantity of and reduce the dispersion of Electrons moving toward said anode and positive ions toward said cathode normal to said dielectric sheet attracting electrons toward the anode and positive ions toward the cathode by applying a high potential across the electrodes depositing one of the types of charged particles on the dielectric sheet.
Claim 18
Independent Claim
157 words
A method of producing an electrostatic image on a dielectric sheet, including the steps of: positioning the dielectric sheet at an electrode in a gap between anode and cathode electrodes positioned adjacent an object to be imaged; passing x-rays through said object and one of said electrodes; absorbing incoming X rays in the gap by maintaining in the gap an X-ray opaque gas of atomic number at least 36 at superatomosperhic pressure and generating electrons and positive ions in the gas, and the gas in the gap moderating the energy of and reducing the mean free path of said electrons to increase the quantity of and reduce the dispersion of Electrons moving toward said anode and positive ions toward said cathode normal to said dielectric sheet attracting electrons toward the anode and positive ions toward the cathode by applying a high potential across the electrodes depositing one of the types of charged particles on the dielectric sheet.
Claim 19
Dependent Claim
34 words
A method as defined in claim 16 including maintaining the product of gap width at the zone of X-ray incidence times the gas pressure in the gap at at least about 10 mm atmospheres.
Claim 20
Dependent Claim
40 words
A method as defined in claim 16 including maintaining the product of gap width at the zone of X-ray incidence times the gas pressure in the gap in the range of about 10 mm atmospheres to about 200 mm atmospheres.
Claim 21
Dependent Claim
37 words
A method as defined in claim 18 including selecting the electrode potential to operate the system in the plateau of the Townsend curve of voltage vs. current so that substanitally no electron avalanching occurs in the gap.
Claim 22
Dependent Claim
37 words
A method as defined in claim 16 including selecting the electrode potential to operate the system in the plateau of the Townsend curve of voltage vs. current so that substantially no electron avalanching occurs in the gap.
Claim 23
Dependent Claim
19 words
A method as defined in claim 16 including positioning the dielectric sheet at the anode and depositing electrons thereon.
Claim 24
Dependent Claim
20 words
A method as defined in claim 16 including positioning the dielectric sheet at the cathode and depositing positive ions thereon.
References Cited (Backward Citations)
US3526767A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |