Patent US4029558A successfully refreshed from Google Patents.
US4029558A
Expired / Lapsed
US
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Isotope enrichment by frequency-tripled temperature tuned neodymium laser photolysis of formaldehyde
Assignee: Energy Research and Development Administration ERDA
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Filing: 1976-10-22
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Granted: 1977-06-14
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Expires: 1996-10-22
Abstract
Abstract Enrichment of carbon, hydrogen and/or oxygen isotopes by means of isotopically selective photo-predissociation of formaldehyde is achieved by irradiation provided by a frequency-tripled, temperature tuned neodymium laser.
Inventors
- 👤 John B. Marling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:28
CPC Classifications
B; B01; B01J; B01J19/00; B01J19/08; B01J19/12; B01J19/121; B01D; B01D59/00; B01D59/34; C; C01; C01B; C01B4/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
138 words
A method for separating isotopes of at least one of the elements carbon, hydrogen and oxygen by selective photo-predissociation of formaldehyde which comprises: subjecting a gaseous formaldehyde isotope source material to laser radiation at a given wavelength in the range of from about 352 nanometers to about 355 nanometers which excites those molecules of formaldehyde containing a desired isotope without substantially exciting those molecules of formaldehyde containing an undesired isotope of the same element, the excited molecules thereby dissociating to form a product enriched in the desired isotope without substantial dissociation of unexcited molecules, providing said laser radiation by means of a neodymium laser in a frequency-tripled configuration, said laser being tuned to said given wavelength by varying the temperature of the laser crystal, and separating the dissociation product enriched in the desired isotope from the reaction system.
Claim 2
Independent Claim
138 words
A method for separating isotopes of at least one of the elements carbon, hydrogen and oxygen by selective photo-predissociation of formaldehyde which comprises: subjecting a gaseous formaldehyde isotope source material to laser radiation at a given wavelength in the range of from about 352 nanometers to about 355 nanometers which excites those molecules of formaldehyde containing a desired isotope without substantially exciting those molecules of formaldehyde containing an undesired isotope of the same element, the excited molecules thereby dissociating to form a product enriched in the desired isotope without substantial dissociation of unexcited molecules, providing said laser radiation by means of a neodymium laser in a frequency-tripled configuration, said laser being tuned to said given wavelength by varying the temperature of the laser crystal, and separating the dissociation product enriched in the desired isotope from the reaction system.
Claim 3
Dependent Claim
25 words
A method according to claim 1 wherein the temperature of the laser crystal is varied by varying the temperature of the laser crystal cooling fluid.
Claim 4
Dependent Claim
26 words
A method according to claim 1 wherein the temperature of the laser crystal is varied in the range between about -40° C and about 100° C.
Claim 5
Dependent Claim
16 words
A method according to claim 1 wherein the neodymium laser is a neodymium-yttrium aluminum garnet laser.
Claim 6
Dependent Claim
32 words
A method according to claim 4 wherein the given wavelength is in the range of from about 353.77 to about 353.91 and is provided by the laser transition at about 1061 nanometers.
Claim 7
Dependent Claim
34 words
A method according to claim 4 wherein the given wavelength is in the range of from about 354.60 nanometers to about 354.83 nanometers and is provided by the laser transition at about 1064 nanometers.
Claim 8
Dependent Claim
13 words
A method according to claim 1 wherein the desired isotope is 13 C.
Claim 9
Dependent Claim
13 words
A method according to claim 1 wherein the desired isotope is 18 0.
Claim 10
Dependent Claim
13 words
A method according to claim 1 wherein the desired isotope is 17 0.
Claim 11
Dependent Claim
12 words
A method according to claim 1 wherein the desired isotope is deuterium.
Claim 12
Dependent Claim
31 words
A method according to claim 1 further defined by providing said laser with an intracavity etalon and adjusting said etalon for the maximum ratio of desired to undesired isotope formaldehyde fluorescence.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-13 | 1980-12-13 | 1981-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-13 | 1984-12-13 | 1985-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-13 | 1988-12-13 | 1989-06-14 | $7700.00 | Window Closed / Lapsed |