US3725775A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-oscillating helium magnetometer
Assignee: Individual
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Filing: 1968-08-23
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Granted: 1973-04-03
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Expires: 1988-08-23
Abstract
Abstract A self-oscillating magnetometer having a metastable helium atom absorption cell optically pumped with the light emission line of 3888.65 Angstroms wavelength. The amount of light transmitted through the absorption cell at this wavelength is sensed by a photo-detector which has relatively high spectral response at the same wavelength. The photo-detector output signal provides a signal to a pair of Helmholtz coils for generating an RF resonance frequency field in the absorption cell and a signal to a display indicative of the ambient magnetic field strength.
Inventors
- 👤 R Gasser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:55
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/24; G01R33/26
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
86 words
A self-oscillating metastable helium magnetometer comprising: light means emitting light of 3888.65 Angstrom wavelength for optically pumping metastable helium atoms to the 33PJ state; quantum means receiving the light and absorbing the light at a rate proportional to the ambient magnetic field intensity; measuring means optimally responsive to light at the emitted wavelength transmitted through said quantum means for producing an output signal indicative of the ambient magnetic field intensity; and resonance means operatively connected to said quantum means and said measuring means for maintaining self-oscillation.
Claim 2
Dependent Claim
86 words
A self-oscillating metastable helium magnetometer comprising: light means emitting light of 3888.65 Angstrom wavelength for optically pumping metastable helium atoms to the 33PJ state; quantum means receiving the light and absorbing the light at a rate proportional to the ambient magnetic field intensity; measuring means optimally responsive to light at the emitted wavelength transmitted through said quantum means for producing an output signal indicative of the ambient magnetic field intensity; and resonance means operatively connected to said quantum means and said measuring means for maintaining self-oscillation.
Claim 3
Dependent Claim
63 words
A magnetometer according to claim 1 wherein said light means includes: first circuit means for providing initial and sustaining output signals of a predetermined voltage and frequency; emission means receiving the first circuit means output signal and emitting light in the helium spectrum; and optical means receiving the light and producing a linearly and circularly polarized collimated light beam of 3888.65 Angstroms wavelength.
Claim 4
Dependent Claim
56 words
A magnetometer according to claim 2 wherein said optical means includes: a collimating lens receiving tHe emitted light and producing a collimated light beam; a light filter interposed in said light beam transmitting therethrough light of only 3888.65 Angstroms wavelength; and polarizer means interposed in the filtered light beam for linearly and circularly polarizing the light.
Claim 5
Dependent Claim
102 words
A magnetometer according to claim 3 wherein said first circuit means includes: an ignition circuit having a momentary high voltage output signal; an ignition filter receiving the ignition circuit output signal and producing an initial high voltage output signal and producing a high voltage output signal of a predetermined frequency bandwidth for initiating light emission; an exciter circuit providing a signal of frequency and voltage sufficient to sustain light emission after cessation of said ignition filter output signal; and a lamp matching network receiving the ignition filter and exciter circuit output signals and producing an impedance-matched output signal to said emission means.
Claim 6
Dependent Claim
52 words
A magnetometer according to claim 4 wherein said quantum means includes: a helium absorption cell interposed in the filtered and polarized light beam; and an absorption cell matching network receiving said filter and exciter circuit output signals and producing an impedance-matched output signal to said absorption cell or ionizing the helium therein.
Claim 7
Dependent Claim
80 words
A magnetometer according to claim 5 wherein said measuring means includes: a focusing lens receiving the light transmitted through said absorption cell and focusing the light; a photo-detector optimally responsive to light emission of 3888.65 Angstroms receiving the focused light and producing an electrical output signal proportional to the intensity of the light transmitted through said absorption cell; and display means receiving an output signal from said second circuit means and producing an indication of the ambient magnetic field intensity.
Claim 8
Dependent Claim
61 words
A magnetometer according to claim 6 wherein said resonance means includes: second circuit means receiving the photo-detector output signal and producing an amplified and phase adjusted output signal; and a pair of Helmholtz resonance coils positioned about said absorption cell receiving the second circuit means output signal and producing a resonance field in said absorption cell transverse to the light beam.
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) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |