4 TABLE I: Simulation results of isotope separation from single-photon atomic sorting. year. A supersonic beam can be operated in a continuous mode, and the flux is limited only by available vacuum pump speed. Diffusion pumps are available with pump- ing speeds of over 60,000 L/s, so that large scale separa- tion seems feasible. The next step will be a first experi- mental demonstration of single-photon atomic sorting. M.G.R. acknowledges support from the State of Texas Advanced Research Program and the Sid W. Richardson Foundation. Target Natural Laser Ground Guiding Enrich- Collected Isotope Abundance λ (nm) State Length (m) ment Isotope % $^{6}$Li 7.6% 670.96 $^{2}$S 1 / 2 Quad. 0.5 95.0% 36.8% $^{44}$Ca 2.1% 272.2 $^{1}$S 0 Hex. 2.0 99.9% 9.0% $^{150}$Nd 5.6% 471.9 $^{5}$I 4 Hex. 2.0 97.9% 23.0% FIG. 5: The radial positions of the neodymium isotopes as they enter the magnetic gradient that separates them isotopi- cally, followed by their radial positions upon exiting. Initial radial position (mm) 0 2 4 6 8 10 12 14 counts (atoms/s) 10 20 30 40 50 60 70 80 15 10 Nd, 5.6% 150 Nd, 94.4% 142-148 Final radial position (mm) 0 2 4 6 8 10 12 14 counts (atoms/s) 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 15 10 Nd, 97.9% 150 Nd, 2.1% 142-148 hexapole magnetic field was a 2 m long tube like the one described for $^{44}$Ca but without the bend. Similar separation results can be achieved using a 1.8 m long tube with a slight 1 cm bend to aid in eliminating unwanted isotopes. The precise shape of this bend could be further tuned to achieve the optimal separation geometry. The isotope $^{150}$Nd is of particular interest because it is a double-beta emitter. Many experiments are cur- rently investigating neutrinoless double beta decay in or- der to determine the neutrino mass and whether neu- trinos are Dirac or Majorana particles [17]. SNO+ is one such experiment currently under development, and it plans to use a large amount of enriched neodymium to search for neutrinoless double beta decay [18]. Enrich- ing neodymium is very difficult and can currently only be done using the atomic vapor laser isotope separation technique [19]. Hopefully this simpler approach can aid in the separation of $^{150}$Nd, as well as other isotopes of interest to physics, medicine, and industry. In conclusion, we have presented single-photon atomic sorting as a very general and scalable approach to iso- tope separation. The efficiency of separation is such that every photon in the laser can provide one atom of iso- topic interest. The laser can be recycled in a multi-pass configuration until it is depleted. To put that in perspec- tive, a laser with 1 Watt power could separate approxi- mately 10 19 atoms per second, or roughly 500 Moles per [1] J. W. Beams and F. B. Haynes, Phys. Rev. 50 , 491 (1936). [2] W. W. Watson, Phys. Rev. 56 , 703 (1939). [3] W. H. Furry, R. C. Jones, and L. Onsager, Phys. Rev. 55 , 1083 (1939). [4] R. J. Bartlett and J. R. Morrey, US Patent 4,105,921, August 8 (1978). [5] A. O. Nier Phys. Rev. 52 , 933 (1937). [6] L. Love Science 182 , 343 (1973). [7] P. A. Bokhan et al. , Laser Isotope Separation in Atomic Vapor , WILEY-VCH Verlag GmbH & Co. KGaA, Wein- heim, (2006). [8] Ralchenko, Yu., Kramida, A.E., Reader, J., and NIST ASD Team (2008) NIST Atomic Spec- tra Database (version 3.1.5) , [Online] Available: http://physics.nist.gov/asd3. National Institute of Standards and Technology, Gaithersburg, MD. [9] M. G. Raizen, Science 324 , 1403 (2009). [10] A. Amirav and U. Even, J. Appl. Phys. 51 , 1 (1980). [11] W. A. van Wijngaarden and J. Li, Phys. Rev. A 49 , 1158 (1994). [12] G. Scoles, ed. Atomic and Molecular Beam Methods , Ox- ford University Press, New York, Vol. 1 and 2, (2000). [13] U. Even, M. Hillenkamp, and S. Keinan, J. Chem. Phys., 118 , 8699 (2003). [14] R. D. Swenumson and U. Even, Rev. Sci. Instrum. 52 , 559 (1980). [15] U. Even and M. G. Raizen, in preparation. [16] V. N. Gorshkov et al. , Astrophysics 17 , 437 (1982). [17] S. Elliot and J. Engel, J. Phys. G 30 , R183 (2004). [18] SNO+, K. Zuber et al. , AIP Conf. Proc. 942 , 101 (2007). [19] S. K. Kovalevich, V. P. Labozin, and G. O. Tsvetkov, Tech. Phys. 50 , 96 (2005). [20] K.C. Kuiper, MS. thesis, Eindhoven University of Tech- nology (2007). [21] J. P. Beardmore, A. J. Palmer, K. C. Kuiper, and R. T. Sang, Rev. Sci. Intrum., 80 , 073105 (2009). [22] W. G. Kaenders et al. , Phys. Rev. A 54 , 5067 (1996).