Patent US4147515A successfully refreshed from Google Patents.
US4147515A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electro-chemical sensors for gas detection in electron tubes
Assignee: United States Department of the Navy
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Filing: 1977-12-22
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Granted: 1979-04-03
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Expires: 1997-12-22
Abstract
Abstract An electro-chemical gas sensor for use in electron tubes comprising a crylline body of BaO formed on a non-interacting (chemically and electrically) substrate and at least two electrodes. The change in conductivity of the barium oxide upon exposure to tube gases may be used to determine the type and quantity of gases contaminating the electron emitter and estimate changes in the emitter's work function or electron emission capability due to gas contamination.
Inventors
- 👤 George A. Haas
- 👤 Richard F. Greene
- 👤 Arnold Shih
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:05
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/002; H; H01; H01J; H01J9/00; H01J9/42
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
164 words
A method of predicting a change in the work function of an emitter in a vacuum container due to contamination by gases present in said vacuum container comprising the steps of: exposing a body of barium oxide to the atmosphere in the vacuum container, said body having a known initial conductivity; and measuring the conductivity of said body after said exposure to the atmosphere in the container, a change in the conductivity indicating a change in the work function of the emitter, said change in work function being given approximately by the change in the conduction-band edge, ΔE c , with respect to the Fermi level of said body, said change in the conduction-band edge, ΔE c , being related to the ratio of the measured conductivity, σ 2 , to the initial conductivity, σ 1 , according to the approximation σ.sub.2 /σ.sub.1 ≈e-(ΔE.sub.c)kT where k is the Boltzmann constant and T is the temperature in degrees Kelvin at which the conductivity is measured.
Claim 2
Independent Claim
164 words
A method of predicting a change in the work function of an emitter in a vacuum container due to contamination by gases present in said vacuum container comprising the steps of: exposing a body of barium oxide to the atmosphere in the vacuum container, said body having a known initial conductivity; and measuring the conductivity of said body after said exposure to the atmosphere in the container, a change in the conductivity indicating a change in the work function of the emitter, said change in work function being given approximately by the change in the conduction-band edge, ΔE c , with respect to the Fermi level of said body, said change in the conduction-band edge, ΔE c , being related to the ratio of the measured conductivity, σ 2 , to the initial conductivity, σ 1 , according to the approximation σ.sub.2 /σ.sub.1 ≈e-(ΔE.sub.c)kT where k is the Boltzmann constant and T is the temperature in degrees Kelvin at which the conductivity is measured.
Claim 3
Dependent Claim
44 words
The method of claim 1 wherein the step of exposing a body of barium oxide to the atmosphere in the vacuum container comprises the step of: exposing a film of barium oxide formed on a noninteracting substrate to the atmosphere in the vacuum container.
Claim 4
Dependent Claim
38 words
The method of claim 1 wherein said step of measuring the conductivity of said body after exposure to the atmosphere in the vacuum container comprises the step of: measuring the conductivity across a predetermined volume of said body.
Claim 5
Dependent Claim
36 words
The method as recited in claim 1 wherein said emitter comprises activated barium oxide and wherein the step of exposing a body of barium oxide comprises the step of exposing a body of activated barium oxide.
Claim 6
Dependent Claim
91 words
A detector for predicting changes in the work function of an emitter in a vacuum tube due to contamination by tube gases comprising: a body of barium oxide having a surface which can be exposed to the atmosphere in said vacuum tube, said body having a known initial conductivity; and means for detecting a change in the conductivity of said body when said body is exposed to said gases, said change in conductivity being related to the change in the work function of the emitter due to contamination by said gases.
Claim 7
Dependent Claim
91 words
A detector for predicting changes in the work function of an emitter in a vacuum tube due to contamination by tube gases comprising: a body of barium oxide having a surface which can be exposed to the atmosphere in said vacuum tube, said body having a known initial conductivity; and means for detecting a change in the conductivity of said body when said body is exposed to said gases, said change in conductivity being related to the change in the work function of the emitter due to contamination by said gases.
Claim 8
Dependent Claim
41 words
The detector as recited in claim 5 wherein said detecting means comprises: at least two spaced electrodes coupled to said body for receiving electric potential therebetween, the current between said electrodes being dependent on the conductivity of said barium oxide body.
Claim 9
Dependent Claim
15 words
The detector as recited in claim 5 wherein said barium oxide body is electrically active.
Claim 10
Dependent Claim
24 words
The detector as recited in claim 7 wherein said barium oxide body is a thin film of barium oxide formed on a noninteracting substrate.
Claim 11
Independent Claim
83 words
A method of detecting gases which contaminate an emitter in a vacuum container comprising the steps of: exposing a body of barium oxide to the atmosphere in the container, said body having a known initial conductivity; and measuring the conductivity of said body after exposure to the atmosphere, a change in the conductivity due to exposure to the atmosphere indicating the presence of contaminating gas and the amount of the change being related to the quantity of gas molecules contaminating contaminating said emitter.
Claim 12
Independent Claim
83 words
A method of detecting gases which contaminate an emitter in a vacuum container comprising the steps of: exposing a body of barium oxide to the atmosphere in the container, said body having a known initial conductivity; and measuring the conductivity of said body after exposure to the atmosphere, a change in the conductivity due to exposure to the atmosphere indicating the presence of contaminating gas and the amount of the change being related to the quantity of gas molecules contaminating contaminating said emitter.
Claim 13
Independent Claim
122 words
A method of detecting the quantity of oxygen molecules contaminating an emitter in a vacuum container comprising the steps of: exposing a thin film of barium oxide to the atmosphere in the container, said film of barium oxide having a known initial conductivity, and measuring the conductivity of said film of barium oxide after exposure to the atmosphere, a change in the conductivity due to exposure to the atmosphere indicating the presence of oxygen and the amount of the change being related to the quantity of oxygen molecules contaminating said emitter, a ten-fold decrease in the ratio of the measured conductivity σ 2 to the initial conductivity σ 1 indicating a ten-fold increase in the quantity of oxygen molecules contaminating said emitter.
Claim 14
Independent Claim
122 words
A method of detecting the quantity of oxygen molecules contaminating an emitter in a vacuum container comprising the steps of: exposing a thin film of barium oxide to the atmosphere in the container, said film of barium oxide having a known initial conductivity, and measuring the conductivity of said film of barium oxide after exposure to the atmosphere, a change in the conductivity due to exposure to the atmosphere indicating the presence of oxygen and the amount of the change being related to the quantity of oxygen molecules contaminating said emitter, a ten-fold decrease in the ratio of the measured conductivity σ 2 to the initial conductivity σ 1 indicating a ten-fold increase in the quantity of oxygen molecules contaminating said emitter.
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) | 1982-04-02 | 1982-10-02 | 1983-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-02 | 1986-10-02 | 1987-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-02 | 1990-10-02 | 1991-04-03 | $7700.00 | Window Closed / Lapsed |