Atomic vapor laser

Atomic vapor laser isotope separation (AVLIS)... 

Atomic- Vapor Laser Isotope-Separation. Although the technology has been around since the 1970s, laser isotope separation has only recently matured to the point of industrialization. In particular, laser isotope separation for the production of fuel and moderators for nuclear power generation is on the threshold of pilot-plant demonstrations in several countries. In the atomic vapor laser isotope-separation (AVLIS) process, vibrationaHy cooled U metal atoms are selectively ionized by means of a high power (1—2 kW) tunable copper vapor or dye laser operated at high (kHz) repetition rates (51,59,60). 

LLNL AVLIS Laser. The first WFS measurements using a Na LGS were performed at LLNL (Max et al., 1994 Avicola et al., 1994). These experiments utilized an 1100 W dye laser, developed for atomic vapor laser isotope separation (AVLIS). The wavefront was better than 0.03 wave rms. The dye laser was pumped by 1500 W copper vapor lasers. They are not well suited as a pump for LGSs because of their 26 kHz pulse rate and 32 ns pulse length. The peak intensity at the Na layer, with an atmospheric transmission of 0.6 and a spot diameter of 2.0 m, is 25 W/cm, 4x the saturation. The laser linewidth and shape were tailored to match the D2 line. The power was varied from 7 to 1100 W on Na layer to study saturation. The spot size was measured to be 7 arcsec FWHM at 1100 W. It reduced to 4.6 arcsec after accounting for satura-... 

Atomic systems, in lasers, 74 666-669 Atomic Vapor Laser Isotope Separation (AVLIS) process, 25 416 Atomic weight, 75 748 Atomization, 77 774-775 in spray coating, 7 69-74 technology of, 23 175 Atomizer operation, concerns related to, 23 195... 

Uranium enrichment using LIS has been exhaustively studied and the conceptual outlines of two different methods can be found in the open literature. These methods are multi-photon dissociation of UF6 (SILEX, or Separation of Isotopes by Laser Excitation) and laser excitation of monatomic uranium vapor (Atomic Vapor Laser Isotope Separation, or AVLIS). Following an enormous investment, AVLIS was used by the United States DOE in the 1980s and early 1990s, but due to the present oversupply of separated uranium, the plant has been shut down. 

These results indicate that long lived autoionization states with excitation cross-sections comparable to those for excitation of bound high-lying states exist in heavy atoms with complex spectra. Transitions to these autoionization states can radically increase the efficiency of photoionization of atoms, a factor very important in atomic vapor laser isotope separation. 

Laser isotope separation is one area where multistep excitation and ionization has great commercial potential. The research and development efforts in atomic vapor laser enrichment of 235y are a major factor contributing to the current research activities in laser excitation and ionization processes. The first paper on selective multistep photoionization of atoms was published in 1971. (.62) Since then numerous review articles( 15, 16 >L7,63 >54, (i5) ave been written on laser isotope separation and, in each review, there is a section on atomic vapor photoionization processes. The subjects of economics and critical parameters have been well covered in previous reviews and will not be discussed in detail here. We... 

Laser isotope separation techniques Laser-based isotope enrichment techniques deploy selective photo-excitation principles to excite a particular isotope as an atom or molecule (Rao 2003). Each device consists of three parts the laser system, the optical system, and the separation module. These methods include the atomic vapor laser isotope separation (AVLIS) that uses a fine-tuned laser beam to selectively ionize vapors of atomic the molecular laser isotope separation (MLIS), and separation of isotopes by laser excitation (SD EX) that use a laser to selectively dissociate or excite molecules. 

A fundamentally different technique is laser isotope separation (LIS) or atomic vapor laser isotope separation (AVLIS). A laser beam is tuned to a wavelength that excites only one isotope of the material and ionizes those atoms preferentially. After the atom is ionized, it can be removed from the sample by applying an electric field. 

J.A. Paisner Atomic vapor laser isotope separation, in [Ref.l0.2,p.253]... 

When the first tunable dye lasers made their appearance late in the 1960s (see Stuke 1992), suggestions were put forward as to the use of resonance stepwise ionization for separating isotopes on the basis of isotope shifts in atomic spectra (Letokhov 1969). Following the first successful experiments on the selective ionization of Rb atoms and their isotopes (Ambartzumian et al. 1971), programs were initiated in a number of countries on laser separation of uranium isotopes ( U/ U) by a method that came to be known as the atomic-vapor-laser-isotope-separation (AVLIS) technique (Paisner... 

Paisner, J. A. (1988). Atomic vapor laser isotope separation. Applied Physics B, 46, 253-260. 

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