Patent Number: 
Section: claims

1. A method for separating isotopes, the method comprising:directing a supersonic beam characterized by an average velocity v and velocity distribution Δv/v, the beam comprising a first isotope and a second isotope, at a single-crystalline surface at an angle of incidence θi such that the first isotope elastically scatters from the surface with a peak angle θf1 and the second isotope elastically scatters from the surface with a peak angle θf2; andselectively collecting the scattered first isotope, the scattered second isotope, or both. 2. The method of claim 1, wherein the first and second isotope each have an atomic mass of 50 AMU or less. 3. The method of claim 1, wherein the first and second isotopes are independently selected from 1H, 2H, 3H, 3He, 4He, 6Li, 7Li, 10B, 11B, 12C, 13C, 14C, 14N, 15N, 16O, 17O, 18O, 24Mg, 25Mg, 26Mg, 28Si, 29Si, 30Si, 32S, 33S, 34S, 36S, 35Cl, 37Cl, 36Ar, 38Ar, 40Ar, 39K, 40K, 41K, 1H1H, 2H2H, 1H2H, 12CH4, 13CH4, 14CH4, 14N14N, 15N15N, 16O16O, 18O18O, 16O18O, 6Li1H, 7Li1H, 35Cl1H, 37Cl1H, 14N1H3, 15N1H3, 1H19F, 2H19F, 28Si1H4, 29Si1H4, and 30Si1H4. 4. The method of claim 1, wherein the velocity distribution Δv/v is no more than 10%. 5. The method of claim 1, wherein the single-crystalline surface is characterized by a surface atom spacing of no more than 7.5 Å. 6. The method of claim 1, wherein the single-crystalline surface is characterized by a Debye temperature of at least 100 K. 7. The method of claim 1, wherein the single-crystalline surface is selected from diamond, hydrogen terminated diamond, graphite, graphene, CH3—Si(111), CH3—Ge(111), LiF, NaCl, GaAs, Ni, Pt, Au, O or H covered crystalline metal, and crystallized self-assembled alkane thiol. 8. The method of claim 1, wherein the step of selective collection is carried out by positioning a collection surface at θf1, a collection surface at θf2, or both. 9. The method of claim 1, wherein the method is characterized by an enrichment factor of at least 2 for the scattered first isotope, the scattered second isotope, or both. 10. An apparatus for separating isotopes, the apparatus comprising:a source configured to provide a supersonic beam characterized by an average velocity v and velocity distribution Δv/v, the beam comprising a first isotope and a second isotope, wherein the apparatus is further configured to direct the supersonic beam at a single-crystalline surface at an angle of incidence θi such that the first isotope elastically scatters from the surface with a peak angle θf1 and the second isotope elastically scatters from the surface with a peak angle θf2; anda collector configured to selectively collect the scattered first isotope, the scattered second isotope, or both, as a function of angle θf, or time-of-flight, or both. 11. The apparatus of claim 10, wherein the first and second isotope each have an atomic mass of 50 AMU or less. 12. The apparatus of claim 10, wherein the first and second isotopes are independently selected from 1H, 2H, 3H, 3He, 4He, 6Li, 7Li, 10B, 11B, 12C, 13C, 14C, 14N, 15N, 16O, 17O, 18O, 24Mg, 25Mg, 26Mg, 28Si, 29Si, 30Si, 32S, 33S, 34S, 36S, 35Cl, 37Cl, 36Ar, 38Ar, 40Ar, 39K, 40K, 41K, 1H1H, 2H2H, 1H2H, 12CH4, 13CH4, 14CH4, 14N14N, 15N15N, 16O16O, 18O18O, 16O18O, 6Li1H, 7Li1H, 35Cl1H, 37Cl1H, 14N1H3, 15N1H3, 1H19F, 2H19F, 28Si1H4, 29Si1H4, and 30Si1H4. 13. The apparatus of claim 10, wherein the velocity distribution Δv/v is no more than 10%. 14. The apparatus of claim 10, further comprising the single-crystalline surface wherein the single-crystalline surface is characterized by a surface atom spacing of no more than 7.5 Å. 15. The apparatus of claim 10, further comprising the single-crystalline surface wherein the single-crystalline surface is characterized by a Debye temperature of at least 100 K. 16. The apparatus of claim 10, further comprising the single-crystalline surface wherein the single-crystalline surface is selected from diamond, hydrogen terminated diamond, graphite, graphene, CH3—Si(111), CH3—Ge(111), LiF, NaCl, GaAs, Ni, Pt, Au, O or H covered crystalline metal, and crystallized self-assembled alkane thiol. 17. The apparatus of claim 10, wherein the collector comprises a first collection surface positioned at θf1 and a second collection surface positioned at θf2. 18. The apparatus of claim 10, wherein the apparatus is characterized by the ability to provide an enrichment factor of at least 2 for the scattered first isotope, the scattered second isotope, or both.