Patent US3922555A successfully refreshed from Google Patents.
US3922555A
Expired / Lapsed
US
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Portable instrument for selectively detecting alpha-particles derived from radon
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
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Filing: 1973-07-10
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Granted: 1975-11-25
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Expires: 1993-07-10
Abstract
Abstract A portable instrument of the pocket type designed primarily for monitoring atmospheric contamination in uranium mines by selectively detecting the Alpha -particles emitted simultaneously by the daughter products of radon, namely radium A and radium C''. The instrument comprises in combination a tube containing a suction fan for drawing external air through a filter which retains the Alpha -emitting aerosols, a detector in which the Alpha -particles corresponding to the respective energies of the Alpha -emissions of radium A and of radium C'' are detected separately, and two collimators placed between the filter and the detector.
Inventors
- 👤 Anne Marie Chapuis
- 👤 Danielle Dajlevic
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:56
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/17; G01T1/178; G01T5/00; G01T5/10; G01T7/00; G01T7/02; G01T7/04; G21; G21K; G21K1/00; G21K1/02; Y; Y10; Y10S; Y10S250/00; Y10S250/02
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
98 words
A PORTABLE INSTRUMENT FOR SELECTIVELY DETECTING THE ALPHAPARTICLES EMITTED SIMULTANEOUSLY BY RADIUM A AND RADIUM C'' WHICH ARE DERIVED FROM RADON AND MORE PARTICULARLY FOR MONITORING THE ATMOSPHEREIN MINES, WHEREIN SAID INSTRUMENT COMPRISES IN COMBINATION: A DEVICE FOR SAMPLING AIR THROUGH A FILTER WHICH RETAIN THE A-EMITTING AEROSOLS, A DETECTOR IN WHICH THE A-PARTICLES CORRESPONDING TO THE RESPECTIVE ENERGIES OF THE A-EMISSIONS OF RADIUM A AND OF RADIUM C'' ARE DETECTED SEPARATELY, TWO COLLIMATORS PLACED BETWEEN THE FILTER AND THE DETECTOR WHEREBY SAID COLLIMATORS DIRECT THE ALPHA RADIATION FROM THE AEROSOLS COLLECTED BY SAID FILTER TO SAID DETECTOR.
Claim 2
Dependent Claim
98 words
A PORTABLE INSTRUMENT FOR SELECTIVELY DETECTING THE ALPHAPARTICLES EMITTED SIMULTANEOUSLY BY RADIUM A AND RADIUM C'' WHICH ARE DERIVED FROM RADON AND MORE PARTICULARLY FOR MONITORING THE ATMOSPHEREIN MINES, WHEREIN SAID INSTRUMENT COMPRISES IN COMBINATION: A DEVICE FOR SAMPLING AIR THROUGH A FILTER WHICH RETAIN THE A-EMITTING AEROSOLS, A DETECTOR IN WHICH THE A-PARTICLES CORRESPONDING TO THE RESPECTIVE ENERGIES OF THE A-EMISSIONS OF RADIUM A AND OF RADIUM C'' ARE DETECTED SEPARATELY, TWO COLLIMATORS PLACED BETWEEN THE FILTER AND THE DETECTOR WHEREBY SAID COLLIMATORS DIRECT THE ALPHA RADIATION FROM THE AEROSOLS COLLECTED BY SAID FILTER TO SAID DETECTOR.
Claim 3
Dependent Claim
34 words
A detector according to claim 1, wherein the detector is fitted with sensitive layers associated with screens having different thicknesses which correspond to the respective collimators and select the particles according to their energy.
Claim 4
Dependent Claim
16 words
A detector according to claim 2, wherein the sensitive layers are fabricated from a cellulose compound.
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 |