US3922541A
Expired / Lapsed
US
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Methods and apparatus for stabilizing the gain of a radiation detector
Assignee: Schlumberger Technology Corp
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Filing: 1973-12-21
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Granted: 1975-11-25
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Expires: 1993-12-21
Abstract
Abstract In accordance with an illustrative embodiment of the present invention, a technique for stabilizing the gain of a radiation detector is described. In this technique, a reference radiation source having a predetermined energy spectrum is located adjacent, or enclosed within, a scintillator of a radiation detector. Those signals produced by the radiation detector which represent energies within an energy range defined by the reference source energy spectrum are selected and used to determine the relationship between the energy spectrum of the reference source and the energy spectrum of the selected detector signals. From this relationship, a reference signal is generated which is used to adjust the radiation detector gain in a nonlinear manner to cause the energy spectrum of the selected radiation detector signals to correspond to that of the reference radiation source.
Inventors
- 👤 Bronislav Seeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:36
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/12; G01T; G01T1/00; G01T1/36; G01T1/40
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
139 words
Earth formation exploring apparatus for stabilizing the gain of a radiation detector, comprising: a. an earth formation exploring means for carrying radiation source means for irradiating an earth formation with radiation, a nearby detector means for detecting radiation and producing signals representative thereof, and reference radiation source means for emitting radiation having a predetermined energy spectrum; b. means responsive to said signals for selecting only those of said produced signals which represent energies within a range representative of the range of said predetermined energy spectrum to produce a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and the energy spectrum of said selected signals; and c. means responsive to said reference signal for applying a nonlinear correction to said detector means to maintain a relatively stable gain for said detector means.
Claim 2
Dependent Claim
139 words
Earth formation exploring apparatus for stabilizing the gain of a radiation detector, comprising: a. an earth formation exploring means for carrying radiation source means for irradiating an earth formation with radiation, a nearby detector means for detecting radiation and producing signals representative thereof, and reference radiation source means for emitting radiation having a predetermined energy spectrum; b. means responsive to said signals for selecting only those of said produced signals which represent energies within a range representative of the range of said predetermined energy spectrum to produce a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and the energy spectrum of said selected signals; and c. means responsive to said reference signal for applying a nonlinear correction to said detector means to maintain a relatively stable gain for said detector means.
Claim 3
Dependent Claim
109 words
Apparatus for stabilizing the gain of a signal producing radiation detector having an associated reference radiation source with a predetermined energy spectrum, comprising: a. means responsive to signals derived from said radiation detector for selecting only those of said signals which represent energies within a range representative of the range of said predetermined energy spectrum to produce a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and the energy spectrum of said selected signals; and b. means reponsive to said reference signal for applying a non-linear Correction to said detector means to maintain a relatively stable gain for said detector means.
Claim 4
Dependent Claim
109 words
Apparatus for stabilizing the gain of a signal producing radiation detector having an associated reference radiation source with a predetermined energy spectrum, comprising: a. means responsive to signals derived from said radiation detector for selecting only those of said signals which represent energies within a range representative of the range of said predetermined energy spectrum to produce a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and the energy spectrum of said selected signals; and b. means reponsive to said reference signal for applying a non-linear Correction to said detector means to maintain a relatively stable gain for said detector means.
Claim 5
Dependent Claim
144 words
Earth formation exploring apparatus for stabilizing the gain of a radiation detector means, comprising: a. an earth formation exploring means for carrying radiation source means for irradiating an earth formation with radiation, a nearby detector means for detecting radiation and producing signals representative thereof, and reference radiation source means for emitting radiation having a predetermined energy spectrum; b. means responsive to said signals for detemining the energy spectrum of those signals produced by said detector means which should, except for gain changes in said detector means, be representative of said predetermined energy spectrum and producing a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and said determined energy spectrum; and c. means responsive to said reference signal for applying a non-linear correction to said detector means to maintain a relatively stable gain for said detector means.
Claim 6
Dependent Claim
144 words
Earth formation exploring apparatus for stabilizing the gain of a radiation detector means, comprising: a. an earth formation exploring means for carrying radiation source means for irradiating an earth formation with radiation, a nearby detector means for detecting radiation and producing signals representative thereof, and reference radiation source means for emitting radiation having a predetermined energy spectrum; b. means responsive to said signals for detemining the energy spectrum of those signals produced by said detector means which should, except for gain changes in said detector means, be representative of said predetermined energy spectrum and producing a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and said determined energy spectrum; and c. means responsive to said reference signal for applying a non-linear correction to said detector means to maintain a relatively stable gain for said detector means.
Claim 7
Dependent Claim
116 words
Apparatus for stabilizing the gain of a signal producing radiation detector means, having an associated reference radiation source with a predetermined energy spectrum, comprising; a. means responsive to said signals derived from said detector means for determining the energy spectrum of those signals produced by said detector means which should, except for gain changes in said detector means, be representative of said predetermined energy spectrum and producing a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and said determined energy spectrum; and b. means responsive to said reference signal for applying a non-linear correction to said detector means to maintain a relatively stable gain for said detector means.
Claim 8
Dependent Claim
116 words
Apparatus for stabilizing the gain of a signal producing radiation detector means, having an associated reference radiation source with a predetermined energy spectrum, comprising; a. means responsive to said signals derived from said detector means for determining the energy spectrum of those signals produced by said detector means which should, except for gain changes in said detector means, be representative of said predetermined energy spectrum and producing a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and said determined energy spectrum; and b. means responsive to said reference signal for applying a non-linear correction to said detector means to maintain a relatively stable gain for said detector means.
Claim 9
Independent Claim
104 words
A method of stabilizing the gain of a signal producing radiation detector having an associated reference radiation source with a predetermined energy spectrum, comprising: a. determining the energy spectrum of those signals produced by said detector means which should, except for gain changes in said detector means, be representative of said predetermined energy spectrum and producing a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and said determined energy spectrum; and b. applying a non-linear correction to said detector means in response to said reference signal to maintain a relatively stable gain for said detector means.
Claim 10
Independent Claim
104 words
A method of stabilizing the gain of a signal producing radiation detector having an associated reference radiation source with a predetermined energy spectrum, comprising: a. determining the energy spectrum of those signals produced by said detector means which should, except for gain changes in said detector means, be representative of said predetermined energy spectrum and producing a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and said determined energy spectrum; and b. applying a non-linear correction to said detector means in response to said reference signal to maintain a relatively stable gain for said detector means.
Claim 11
Dependent Claim
141 words
An earth formation exploring method for stabilizing the gain of a radiation detector, comprising: a. moving through a borehole an earth formation exploring means which carries radiation source means for irradiating an earth formation with radiation, a nearby detector means for detecting radiation and producing signals representative thereof, and reference radiation source means for emitting radiation having a predetermined energy spectrum; b. determining the energy spectrum of those signals produced by said detector means which should, except for gain changes in said detector means, be representative of said predetermined energy spectrum and producing a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and said determined energy spectrum; and c. applying a non-linear correction to said detector means in response to said reference signal to maintain a relatively stable gain for said detector means.
Claim 12
Dependent Claim
141 words
An earth formation exploring method for stabilizing the gain of a radiation detector, comprising: a. moving through a borehole an earth formation exploring means which carries radiation source means for irradiating an earth formation with radiation, a nearby detector means for detecting radiation and producing signals representative thereof, and reference radiation source means for emitting radiation having a predetermined energy spectrum; b. determining the energy spectrum of those signals produced by said detector means which should, except for gain changes in said detector means, be representative of said predetermined energy spectrum and producing a reference signal representative of the relationship between said predetermined energy spectrum from the reference radiation source and said determined energy spectrum; and c. applying a non-linear correction to said detector means in response to said reference signal to maintain a relatively stable gain for said detector means.
Claim 13
Dependent Claim
16 words
Apparatus according to claim 1 wherein said correction non-linearity as a function of said reference signal.
Claim 14
Dependent Claim
36 words
Apparatus according to claim 1 wherein a selected change in said reference signal is a function of the magnitude of detector gain instability and said correction non-linearity is a function of said reference Signal selected change.
Claim 15
Dependent Claim
29 words
Apparatus according to claim 1 wherein said correction non-linearity is proportional to said reference signal with a coefficient of proportionality that is an increasing function of detector gain variation.
Claim 16
Dependent Claim
83 words
Apparatus according to claim 1 wherein said predetermined energy spectrum includes a reference peak that is divided about its maximum amplitude into two zones having substantially equal count rates; said produced signals are similarly selected; said reference signal is representative of a gain instability induced, non-equal count rate between the two zones for the selected signals and is approximately proportional to the magnitude of said count rate non-equality; and said non-linear correction is approximately proportional to the hyperbolic sine of the reference signal.
Claim 17
Dependent Claim
16 words
Apparatus according to claim 2 wherein said correction non-linearity is a function of said reference signal.
Claim 18
Dependent Claim
36 words
Apparatus according to claim 2 wherein a selected change in said reference signal is a function of the magnitude of detector gain instability and said correction non-linearity is a function of said reference signal selected change.
Claim 19
Dependent Claim
29 words
Apparatus according to claim 2 whherein said correction non-linearity is proportional to said reference signal with a coefficient of proportionality that is an increasing function of detector gain variation.
Claim 20
Dependent Claim
83 words
Apparatus according to claim 2 wherein said predetermined energy spectrum includes a reference peak that is divided about its maximum amplitude into two zones having substantially equal count rates; said produced signals are similarly selected; said reference signal is representative of a gain instability induced, non-equal count rate between the two zones for the selected signals and is approximately proportional to the magnitude of said count rate non-equality; and said non-linear correction is approximately proportional to the hyperbolic sine of the reference signal.
Claim 21
Dependent Claim
18 words
A method according to claim 5 wherein said applied correction non-linearity is a function of said reference signal.
Claim 22
Dependent Claim
38 words
A method according to claim 5 wherein a selected change in said reference signal is a function of the magnitude of detector gain instability and said applied correction non-linearity is a function of said reference signal selected change.
Claim 23
Dependent Claim
31 words
A method according to claim 5 wherein said applied correction non-linearity is proportional to said reference signal with a coefficient of proportionality that is an increasing function of detector gain variation.
Claim 24
Dependent Claim
18 words
a method according to claim 6 wherein said applied correction non-linearity is a function of said reference signal.
Claim 25
Dependent Claim
38 words
A method according to claim 6 wherein a selected change in said reference signal is a function of the magnitude of detector gain instability and said applied correction non-linearity is a function of said reference signal selected change.
Claim 26
Dependent Claim
31 words
A method according to claim 6 wherein said applied correction non-linearity is proportional to said reference signal with a coefficient of proportionality that is an increasing function of detector gain variation.
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) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |