US3885155A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mass spectrometric determination of carbon 14
Assignee: SRI International Inc
•
Filing: 1973-11-01
•
Granted: 1975-05-20
•
Expires: 1993-11-01
Abstract
Abstract A determination of the amount of carbon 14 in a substance is made simpler and more accurate by introducing the carbon 14 in the form of CO2 into a duoplasmatron negative ion source for a mass spectrometer together with 15N2 producing CN , as the predominate ion. The spectrometer can then accurately detect the amount of carbon 14.
Inventors
- 👤 Michael Anbar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:21
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/26; H01J49/28; H01J49/284; H01J49/286; H01J49/288; H01J49/02; H01J49/10; H01J49/12; H01J49/126
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
77 words
A METHOD OF MEASURING CARBON 14 CONTENT IN A SAMPLE COMPRISING CONVERTING CARBON IN SAID SAMPLE TO CO2, MIXING SAID CO2 WITH 15N2, CONVERTING SAID MIXTURE OF CO2 AND 15N2 IN CN- IONS HAVING DIFFERENT MASSES INCLUDING MASS 29, SEPARATING SAID MASS 29 CN- IONS FROM THE IONS HAVING OTHER MASSES, AND CONUNTING THE NUMBER OF MASS 29 IONS WHICH HAVE BEEN SEPARATED FROM WHICH COUNT THE CONCENTRATION OF CARBON 14 IN SAID SAMPLE CAN BE DETERMINED.
Claim 2
Independent Claim
77 words
A METHOD OF MEASURING CARBON 14 CONTENT IN A SAMPLE COMPRISING CONVERTING CARBON IN SAID SAMPLE TO CO2, MIXING SAID CO2 WITH 15N2, CONVERTING SAID MIXTURE OF CO2 AND 15N2 IN CN- IONS HAVING DIFFERENT MASSES INCLUDING MASS 29, SEPARATING SAID MASS 29 CN- IONS FROM THE IONS HAVING OTHER MASSES, AND CONUNTING THE NUMBER OF MASS 29 IONS WHICH HAVE BEEN SEPARATED FROM WHICH COUNT THE CONCENTRATION OF CARBON 14 IN SAID SAMPLE CAN BE DETERMINED.
Claim 3
Dependent Claim
31 words
A method as recited in claim 1 wherein said step of converting said mixture of CO2 and 15N2 into CN ions comprises introducing said mixture into a duoplasmatron negative ion source.
Claim 4
Dependent Claim
59 words
A method as recited in claim 1 wherein said CN ions having different masses including mass 29 include ions having masses 27 and 28, said method further includes the steps of separating said ions having masses of 27 and 28 from each other, and counting the number of ions having a mass of 27 and a mass of 28.
Claim 5
Independent Claim
95 words
A method of determining the concentration of 14C in a specimen comprising converting the carbon in said specimen to CO2, introducing said CO2 together with 15N2 into a plasma negative ion source, to form CN ions having different masses including masses 27, 28 and 29, separating said CN ions having said different masses into separate ion beams respectively containing CN ions 27, 28 and 29, and counting the number of ions in said separate ion beams with masses 27, 28 and 29, from which counts the concentration of 14C in said sample can be determined.
Claim 6
Independent Claim
95 words
A method of determining the concentration of 14C in a specimen comprising converting the carbon in said specimen to CO2, introducing said CO2 together with 15N2 into a plasma negative ion source, to form CN ions having different masses including masses 27, 28 and 29, separating said CN ions having said different masses into separate ion beams respectively containing CN ions 27, 28 and 29, and counting the number of ions in said separate ion beams with masses 27, 28 and 29, from which counts the concentration of 14C in said sample can be determined.
References Cited (Backward Citations)
US3786249A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |