US5202005A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gadolinium photoionization process
Assignee: United States Department of Energy
•
Filing: 1991-08-14
•
Granted: 1993-04-13
•
Expires: 2011-08-14
Abstract
Abstract A method is provided for selective photoionization of the odd-numbered atomic mass gadolinium isotopes 155 and 157. The selective photoionization is accomplished by circular or linear parallel polarized laser beam energy effecting a three-step photoionization pathway.
Inventors
- 👤 Jeffrey A. Paisner
- 👤 Brian J. Comaskey
- 👤 Christopher A. Haynam
- 👤 Jon H. Eggert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:01
CPC Classifications
B; B01; B01D; B01D59/00; B01D59/34
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
171 words
A method for isotopically selective ionization of an isotope of gadolinium having odd-numbered atomic mass in an atomic vapor containing a plurality of isotopes of gadolinium comprising the steps of applying to said vapor a photon of linearly or circularly polarized radiant energy sufficient to excite said odd-numbered atomic mass isotope of gadolinium from the ground state having an orbital angular momentum, J, value of 2, to a first excited state at an energy level of 16923 cm -1 , relative to the zero energy of said ground state; applying a photon of similarly polarized radiant energy sufficient to excite atoms in said first excited state to a second metastable excited state at an energy level of 32660 cm -1 , relative to the zero energy of said ground state having an orbital angular momentum value, J, of 1; and applying a photon of similarly polarized radiant energy sufficient to excite the atoms in said second excited state to an autoionized state having an orbital angular momentum value, J, of 0.
Claim 2
Independent Claim
171 words
A method for isotopically selective ionization of an isotope of gadolinium having odd-numbered atomic mass in an atomic vapor containing a plurality of isotopes of gadolinium comprising the steps of applying to said vapor a photon of linearly or circularly polarized radiant energy sufficient to excite said odd-numbered atomic mass isotope of gadolinium from the ground state having an orbital angular momentum, J, value of 2, to a first excited state at an energy level of 16923 cm -1 , relative to the zero energy of said ground state; applying a photon of similarly polarized radiant energy sufficient to excite atoms in said first excited state to a second metastable excited state at an energy level of 32660 cm -1 , relative to the zero energy of said ground state having an orbital angular momentum value, J, of 1; and applying a photon of similarly polarized radiant energy sufficient to excite the atoms in said second excited state to an autoionized state having an orbital angular momentum value, J, of 0.
Claim 3
Dependent Claim
24 words
A method according to claim 1 wherein said autoionized state is at an energy level of 50624.7 cm -1 relative to said ground state.
Claim 4
Dependent Claim
92 words
A method according to claim 2 wherein the transition to said first excited state is effected by a copper vapor pumped dye laser tuned to a frequency of 16923 cm -1 , said transition from said first excited state to said second excited state is effected by a copper vapor pumped dye laser tuned to a frequency of 15737 cm -1 , and the transition from said second excited state to said autoionization state is effected by a copper vapor pumped dye laser tuned to a frequency of 17963.8 cm -1 .
Claim 5
Independent Claim
171 words
A method for isotopically selective ionization of a isotope of gadolinium having odd-numbered atomic mass in an atomic vapor containing a plurality of isotopes of gadolinium comprising the steps of applying to said vapor a photon of linearly or circularly polarized radiant energy sufficient to excite said odd-numbered atomic mass isotope of gadolinium from the ground state having an orbital angular momentum, J, value of 2, to a first excited state at an energy level of 17380 cm -1 , relative to the zero energy of said ground state; applying a photon of similarly polarized radiant energy sufficient to excite atoms in said first excited state to a second metastable excited state at an energy level of 34586 cm -1 , relative to the zero energy of said ground state, having an orbital angular momentum value, J, of 1; and applying a photon of similarly polarized radiant energy sufficient to excite the atoms in said second excited state to an autoionized state having an orbital angular momentum value, J, of 0.
Claim 6
Independent Claim
171 words
A method for isotopically selective ionization of a isotope of gadolinium having odd-numbered atomic mass in an atomic vapor containing a plurality of isotopes of gadolinium comprising the steps of applying to said vapor a photon of linearly or circularly polarized radiant energy sufficient to excite said odd-numbered atomic mass isotope of gadolinium from the ground state having an orbital angular momentum, J, value of 2, to a first excited state at an energy level of 17380 cm -1 , relative to the zero energy of said ground state; applying a photon of similarly polarized radiant energy sufficient to excite atoms in said first excited state to a second metastable excited state at an energy level of 34586 cm -1 , relative to the zero energy of said ground state, having an orbital angular momentum value, J, of 1; and applying a photon of similarly polarized radiant energy sufficient to excite the atoms in said second excited state to an autoionized state having an orbital angular momentum value, J, of 0.
Claim 7
Dependent Claim
24 words
A method according to claim 4 wherein said autoionization state is at an energy level of 50624.7 cm -1 relative to said ground state.
Claim 8
Dependent Claim
96 words
A method according to claim 5 wherein the transition from the ground state to said first excited state is effected by a copper vapor pumped dye laser tuned to a frequency of 17380 cm -1 , the transition from said first excited state to said second excited state is effected by a copper vapor pumped dye laser tuned to the frequency of 17205 cm -1 , and the transition from said second excited state to said autoionization state is effected by a copper vapor pumped dye laser tuned to a frequency of 16038.0 cm -1 .
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) | 1996-04-12 | 1996-10-12 | 1997-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-12 | 2000-10-12 | 2001-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-12 | 2004-10-12 | 2005-04-13 | $7700.00 | Window Closed / Lapsed |