US4970391A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiation detector with an ionizable gas atop an integrated circuit
Assignee: ONGUARD SYSTEMS Inc
•
Filing: 1989-02-13
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Granted: 1990-11-13
•
Expires: 2009-02-13
Abstract
Abstract The radiation detector includes tissue equivalent bubbles of plastic defining volumes of gas to be ionized by radiation. One or more integrated circuit (ICs) are disposed below the volumes of gas and a collecting electrode on the IC is in direct contact with the gas. Circuitry for generating an electric field within the volume of gas moves the ions therein to the collecting electrode. The collecting electrode is part of an amplifying circuit disposed within the IC. The output from the amplifier is representative of the collected ions and therefore representative of the radiation. The signal from the amplifier is sent to an interface which conditions, buffers and stores the signal. The radiation dose and dose rate are computed in the interface. A communications section transfers that data from the radiation detector. A separate calibration and display unit calibrates the interface by controlling the conditioning of the signal. An area monitor and air monitor are further enhancements of the radiation detector. The radiation detector includes several circuitry arrangements for minimizing inaccuracies due to leakage currents to the collecting electrode from the amplifying circuit. Such circuitry arrangements include duplicate discharge and amplifying circuits not connected to a functioning collecting electrode; subtracting circuitry for subtracting a signal valued proportional to the leakage current; and a current source inducing current opposite in polarity to the leakage current.
Inventors
- 👤 Arthur E. Uber, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:27
CPC Classifications
H; H01; H01J; H01J47/00; H01J47/02; G; G01; G01T; G01T1/00; G01T1/16; G01T1/185; G01T7/00; G01T7/12; G01T7/125
Claims Analysis
Total Claims: 67
Claim 1
Independent Claim
188 words
A radiation detection system for measuring radiation, the system comprising: a radiation detector having at least one radiation detection subassembly including: means for defining a volume of gas, said gas being a detection medium adapted to be ionized by said radiation; a surface element positioned in direct contact with said gas and being part of said means for defining a volume of gas; means for generating an electric field within said volume of gas and for collecting ions present therein including at least one collecting electrode positioned on said surface element for collecting ions created in said ionizable gas; amplifying means electrically connected to said collecting electrode for generating a signal representative of the collected ions; controlled discharge means for removing charge from said collecting electrode; and means for minimizing inaccuracies in said system due to leakage currents to said collecting electrode from said discharge means or said amplifying means; interface means for buffering said signal generated by said amplifying means; detector control means for controlling said controlled discharge means; and means for supplying power to said at least one radiation detection subassembly and said detector control means.
Claim 2
Dependent Claim
188 words
A radiation detection system for measuring radiation, the system comprising: a radiation detector having at least one radiation detection subassembly including: means for defining a volume of gas, said gas being a detection medium adapted to be ionized by said radiation; a surface element positioned in direct contact with said gas and being part of said means for defining a volume of gas; means for generating an electric field within said volume of gas and for collecting ions present therein including at least one collecting electrode positioned on said surface element for collecting ions created in said ionizable gas; amplifying means electrically connected to said collecting electrode for generating a signal representative of the collected ions; controlled discharge means for removing charge from said collecting electrode; and means for minimizing inaccuracies in said system due to leakage currents to said collecting electrode from said discharge means or said amplifying means; interface means for buffering said signal generated by said amplifying means; detector control means for controlling said controlled discharge means; and means for supplying power to said at least one radiation detection subassembly and said detector control means.
Claim 3
Dependent Claim
43 words
The system of claim 1, wherein an input to said amplifying means at said collecting electrode is sealed within the volume of gas and isolated from moisture, and wherein said collecting electrode is electrically isolated from elements outside of said volume of gas.
Claim 4
Dependent Claim
34 words
The system of claim 1, wherein said controlled discharge means comprises a transistor that unintentionally introduces a leakage current into the collecting electrode, said leakage current being controlled by said means for minimizing inaccuracies.
Claim 5
Dependent Claim
43 words
The system of claim 3, wherein said means for minimizing inaccuracies comprises a current source for inducing current of a polarity opposite to that of the leakage current flowing to the collecting electrode, said current source being controlled by said detector control means.
Claim 6
Dependent Claim
50 words
The system of claim 4, and further comprising a duplicate controlled discharge means and a duplicate amplifying means, said duplicate amplifying means and said duplicate controlled discharge means being not connected to said collecting electrode, and supplying electrical signal information to said detector control means for controlling said current source.
Claim 7
Dependent Claim
53 words
The system of claim 1, and further comprising a duplicate controlled discharge means and a duplicate amplifying means, said duplicate amplifying means and said duplicate controlled discharge means being not connected to said collecting electrode, and producing an output signal fed to said detector control means for minimizing inaccuracies due to leakage current.
Claim 8
Dependent Claim
81 words
The system of claim 1, wherein said controlled discharge means removes charge from said collecting electrode in predetermined size packets of charge, said controlled discharge mans producing as output a pulse for each packet of charge removed from said collecting electrode so that the number of pulses produced as output by said controlled discharge means is a measure of the charge collected on said collecting electrode, and the rate of said pulses is related to the current to the collecting electrode.
Claim 9
Dependent Claim
69 words
The system of claim 7, and further comprising a voltage source, and wherein said controlled discharge means comprises two transistors connected in series between said collecting electrode and said voltage source, said transistors being controlled and switched sequentially so that only one transistor conducts at any one instant in time for removing predetermined size packets of charge from the collecting electrode and delivering said charge to said voltage source.
Claim 10
Dependent Claim
65 words
The system of claim 7, and further comprising counting means forming a part of said detector control means for counting events corresponding to the removal of charge by said controlled discharge means, and wherein said means for minimizing inaccuracies comprises means for controlling said counting means to ignore charge removal events if said charge removal events do not occur more frequently than a predetermined frequency.
Claim 11
Dependent Claim
33 words
The system of claim 1, wherein said means for minimizing inaccuracies comprises means for not permanently electrically connecting said controlled discharge means to said collecting electrode under control of said detector control means.
Claim 12
Dependent Claim
20 words
The system of claim 10, wherein said controlled discharge means uses induced conductivity in the detection medium for controlled discharge.
Claim 13
Dependent Claim
29 words
The system of claim 10, wherein said controlled discharge means uses induced conductivity in the detection medium for controlled discharge, said conductivity being induced by the radiation being measured.
Claim 14
Dependent Claim
74 words
The system of claim 12, wherein said detector control means includes means for sensing successive accumulations of charge on the collecting electrode and said controlled discharge means is connected to the means for supplying power for reversing the polarity of said electric field within said volume of gas for attracting charges of one polarity to said collecting electrode, and then attracting charges of a polarity, opposite to said first polarity, to said collecting electrode.
Claim 15
Dependent Claim
29 words
The system of claim 13, wherein said detector control means controls said controlled discharge means so that measurements can be made while said electric field is of either polarity.
Claim 16
Dependent Claim
37 words
The system of claim 1, and further comprising means within the detector control means for enabling measurement of radiation over a total dose rate range that extends beyond the range of any single unmodified radiation detection subassembly.
Claim 17
Dependent Claim
30 words
The system of claim 15, wherein said detector control means includes selecting means to select a particular radiation detection subassembly for measuring radiation within its predetermined accurate dose rate range.
Claim 18
Dependent Claim
30 words
The system of claim 15, wherein said detector control means selects a signal representative of the collected charge on one of several collecting electrodes from within a radiation detection subassembly.
Claim 19
Dependent Claim
66 words
The system of claim 1, wherein said radiation detection subassembly is capable of sensing charge or current, and further includes means for generating a numeric representation of the collected charge or current, accumulating means for accumulating a numeric representation of the sensed charge or current, and communicating means for communicating said numeric representation upon command of said detector control means, or in accordance with programmed instructions.
Claim 20
Dependent Claim
29 words
The system of claim 18, and further including means for storing numeric information used in the operation and accumulation of said numeric representation of said sensed charge or current.
Claim 21
Dependent Claim
28 words
The system of claim 19, and further comprising error detection and correction means for minimizing errors in communication of said numeric representation of said sensed charge or current.
Claim 22
Dependent Claim
40 words
The system of claim 11, and further comprising an integrated circuit; wherein said amplifying means includes at least one input transistor mounted on said integrated circuit; and wherein said integrated circuit is located in close proximity to said collecting electrode.
Claim 23
Dependent Claim
43 words
The system of claim 21, wherein an input to said amplifying means at said collecting electrode is sealed within the volume of gas and isolated from moisture, and wherein said collecting electrode is electrically isolated from elements outside of said volume of gas.
Claim 24
Dependent Claim
34 words
The system of claim 22, wherein said controlled discharge means comprises a transistor that unintentionally introduces a leakage current into the collecting electrode, said leakage current being controlled by said means for minimizing inaccuracies.
Claim 25
Dependent Claim
43 words
The system of claim 23, wherein said means for minimizing inaccuracies comprises a current source for inducing current of a polarity opposite to that of the leakage current flowing to the collecting electrode, said current source being controlled by said detector control means.
Claim 26
Dependent Claim
51 words
The system of claim 24, an d further comprising a duplicate controlled discharge means and a duplicate amplifying means, said duplicate amplifying means and said duplicate controlled discharge means being not connected to said collecting electrode, and supplying electrical signal information to said detector control mans for controlling said current source.
Claim 27
Dependent Claim
53 words
The system of claim 21, and further comprising a duplicate controlled discharge means and a duplicate amplifying means, said duplicate amplifying means and said duplicate controlled discharge means being not connected to said collecting electrode, and producing an output signal fed to said detector control means for minimizing inaccuracies due to leakage current.
Claim 28
Dependent Claim
81 words
The system of claim 21, wherein said controlled discharge means removes charge from said collecting electrode in predetermined size packets of charge, said controlled discharge means producing as output a pulse for each packet of charge removed from said collecting electrode so that the number of pulses produced as output by said controlled discharge mans is a measure of the charge collected on said collecting electrode, and the rate of said pulses is related to the current to the collecting electrode.
Claim 29
Dependent Claim
69 words
The system of claim 27, and further comprising a voltage source, and wherein said controlled discharge means comprises two transistors connected in series between said collecting electrode and said voltage source, said transistors being controlled and switched sequentially so that only one transistor conducts at any one instant in time for removing predetermined size packets of charge from the collecting electrode and delivering said charge to said voltage source.
Claim 30
Dependent Claim
65 words
The system of claim 27, and further comprising counting means forming a part of said detector control means for counting events corresponding to the removal of charge by said controlled discharge means, and wherein said means for minimizing inaccuracies comprises means for controlling said counting means to ignore charge removal events if said charge removal events do not occur more frequently than a predetermined frequency.
Claim 31
Dependent Claim
33 words
The system of claim 21, wherein said means for minimizing inaccuracies comprises means for not permanently electrically connecting said controlled discharge means to said collecting electrode under control of said detector control means.
Claim 32
Dependent Claim
20 words
The system of claim 30, wherein said controlled discharge means uses induced conductivity in the detection medium for controlled discharge.
Claim 33
Dependent Claim
29 words
The system of claim 30, wherein said controlled discharge means uses induced conductivity in the detection medium for controlled discharge, said conductivity being induced by the radiation being measured.
Claim 34
Dependent Claim
74 words
The system of claim 32, wherein said detector control means includes means for sensing successive accumulations of charge on the collecting electrode and said controlled discharge means is connected to the means for supplying power for reversing the polarity of said electric field within said volume of gas for attracting charges of one polarity to said collecting electrode, and then attracting charges of a polarity, opposite to said first polarity, to said collecting electrode.
Claim 35
Dependent Claim
29 words
The system of claim 33, wherein said detector control means controls said controlled discharge means so that measurements can be made while said electric field is of either polarity.
Claim 36
Dependent Claim
37 words
The system of claim 21, and further comprising means within the detector control means for enabling measurement of radiation over a total dose rate range that extends beyond the range of any single unmodified radiation detection subassembly.
Claim 37
Dependent Claim
30 words
The system of claim 35, wherein said detector control means includes selecting means to select a particular radiation detection subassembly for measuring radiation within its predetermined accurate dose rate range.
Claim 38
Dependent Claim
30 words
The system of claim 35, wherein said detector control means selects a signal representative of the collected charge on one of several collecting electrodes from within a radiation detection subassembly.
Claim 39
Dependent Claim
40 words
The system of claim 21, and further comprising a guard ring mounted on the surface of said integrated circuit, said guard ring being kept at the same potential as said collecting electrode to intercept leakage current to said collecting electrode.
Claim 40
Dependent Claim
32 words
The system of claim 38, wherein said guard ring is sized to minimize induction of voltage onto said collecting electrode due to the presence of nearby conductive material on said integrated circuit.
Claim 41
Dependent Claim
36 words
The system of claim 38, and further comprising a capacitor formed on the integrated circuit connected to the gate of said input transistor for controllably changing the voltage of the gate without inducing a leakage current.
Claim 42
Dependent Claim
66 words
The system of claim 21, wherein said radiation detection subassembly is capable of sensing charge or current, and further includes means for generating a numeric representation of the collected charge or current, accumulating means for accumulating a numeric representation of the sensed charge or current, and communicating means for communicating said numeric representation upon command of said detector control means, or in accordance with programmed instructions.
Claim 43
Dependent Claim
29 words
The system of claim 41, and further including means for storing numeric information used in the operation and accumulation of said numeric representation of said sensed charge or current.
Claim 44
Dependent Claim
28 words
The system of claim 42, and further comprising error detection and correction means for minimizing errors in communication of said numeric representation of said sensed charge or current.
Claim 45
Dependent Claim
37 words
The system of claim 1, and further comprising an unpackaged integrated circuit; wherein said surface element in mounted on said unpackaged integrated circuit; and wherein said amplifying means includes an input transistor mounted on said integrated circuit.
Claim 46
Dependent Claim
42 words
The system of claim 44, wherein an input to said amplifying means at said collecting electrode is sealed within the volume of gas and isolated from moisture, and said collecting electrode is electrically isolated from elements outside of said volume of gas.
Claim 47
Dependent Claim
34 words
The system of claim 44, wherein said controlled discharge means comprises a transistor that unintentionally introduces a leakage current into the collecting electrode, said leakage current being controlled by said means for minimizing inaccuracies.
Claim 48
Dependent Claim
41 words
The system of claim 46, wherein said means for minimizing inaccuracies comprises a current source for inducing current of opposite polarity than the leakage current to flow to the collecting electrode, said current source being controlled by the detector control means.
Claim 49
Dependent Claim
58 words
The system of claim 47, and further comprising a duplicate controlled discharge means and a duplicate amplifying means, said duplicate amplifying means and said duplicate controlled discharge means not being connected to said collecting electrode, said duplicate controlled discharge means and duplicate amplifying means supplying electrical signal information to said detector control mans for controlling said current source.
Claim 50
Dependent Claim
53 words
The system of claim 44, and further comprising a duplicate controlled discharge means and a duplicate amplifying means, said duplicate amplifying means and said duplicate controlled discharge being not connected to said collecting electrode, and producing an output signal fed to said detector controller means for minimizing inaccuracies due to the leakage current.
Claim 51
Dependent Claim
81 words
The system of claim 44, wherein said controlled discharge means removes charge from said collecting electrode in predetermined size packets of charge, said controlled discharge means producing as output a pulse for each packet of charge removed from said collecting electrode so that the number of pulses produced as output by said controlled discharge means is a measure of the charge collected on said collecting electrode, and the rate of said pulses is related to the current to the collecting electrode.
Claim 52
Dependent Claim
69 words
The system of claim 50, and further comprising a voltage source; and wherein said controlled discharge means comprises two transistors connected in series between said collecting electrode and said voltage source, said transistors being controlled and switched sequentially so that only one transistor conducts at any one instant in time for removing predetermined size packets of charge from the collecting electrode and delivering said charge to said voltage source.
Claim 53
Dependent Claim
64 words
The system of claim 50, and further comprising counting means forming a part of said detector control means for counting events corresponding to the removal of charge by said controlled discharge means, and wherein said means for minimizing inaccuracies comprises means for controlling said counting means to ignore charge removal events if said charge removal events do not occur greater than a predetermined frequency.
Claim 54
Dependent Claim
33 words
The system of claim 44, wherein said means for minimizing inaccuracies comprises means for not permanently electrically connecting said controlled discharge means to said collecting electrode under control of said detector control means.
Claim 55
Dependent Claim
20 words
The system of claim 53, wherein said controlled discharge means uses induced conductivity in the detection medium for controlled discharge.
Claim 56
Dependent Claim
29 words
The system of claim 53, wherein said controlled discharge means uses induced conductivity in the detection medium for controlled discharge, said conductivity being induced by the radiation being measured.
Claim 57
Dependent Claim
74 words
The system of claim 55, wherein said detector control means includes means for sensing successive accumulations of charge on the collecting electrode and said controlled discharge means is connected to the means for supplying power for reversing the polarity of said electric field within said volume of gas for attracting charges of one polarity to said collecting electrode, and then attracting charges of a polarity, opposite to said first polarity, to said collecting electrode.
Claim 58
Dependent Claim
29 words
The system of claim 56, wherein said detector control mans controls said controlled discharge means so that measurements can be made while said electric field is of either polarity.
Claim 59
Dependent Claim
37 words
The system of claim 44, and further comprising means within the detector control means for enabling measurement of radiation over a total dose rate range that extends beyond the range of any single unmodified radiation detection subassembly.
Claim 60
Dependent Claim
30 words
The system of claim 58, wherein said detector control means includes selecting means to select a particular radiation detection subassembly for measuring radiation within its predetermined accurate dose rate range.
Claim 61
Dependent Claim
30 words
The system of claim 58, wherein said detector control means selects a signal representative of the collected charge on one of several collecting electrode from within a radiation detection subassembly.
Claim 62
Dependent Claim
40 words
The system of claim 44, and further comprising a guard ring mounted on the surface of said integrated circuit, said guard ring being kept at the same potential as said collecting electrode to intercept leakage current to said collecting electrode.
Claim 63
Dependent Claim
32 words
The system of claim 61, wherein said guard ring is sized to minimize induction of voltage onto said collecting electrode due to the presence of nearby conductive material on said integrated circuit.
Claim 64
Dependent Claim
36 words
The system of claim 61, and further comprising a capacitor formed on the integrated circuit connected to the gate of said input transistor for controllably changing the voltage of the gate without inducing a leakage current.
Claim 65
Dependent Claim
66 words
The system of claim 44, wherein said radiation detection subassembly is capable of sensing charge or current, and further includes means for generating a numeric representation of the collected charge or current, accumulating means for accumulating a numeric representation of the sensed charge or current, and communicating means for communicating said numeric representation upon command of said detector control means, or in accordance with programmed instructions.
Claim 66
Dependent Claim
29 words
The system of claim 64, and further including means for storing numeric information used in the operation and accumulation of said numeric representation of said sensed charge or current.
Claim 67
Dependent Claim
28 words
The system of claim 65, and further comprising error detection and correction means for minimizing errors in communication of said numeric representation of said sensed charge or current.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-11-12 | 1994-05-14 | 1994-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-12 | 1998-05-14 | 1998-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-12 | 2002-05-14 | 2002-11-13 | $7700.00 | Window Closed / Lapsed |