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During Atomic Vapor Laser Isotope Separation process, the contamination of collector plate by the unwanted neutral atoms scattering onto it, is a major parameter deciding the enrichment factor. The selective photo-ionization by tunable laser beam is pulsed whereas the neutral atoms scattering onto the collector plate is occurring continuously. Although the collector plates are shielded from the atomic beam by using slits, a small fraction of atoms do scatter onto the collector plate due to scattering from slits, atom-atom collision and also by reflection & re-evaporation from tails product collector. Experimental is carried out to quantitatively measure the percentage of neutral atoms scattering onto the product collector using copper atomic beam. The atomic beam is generated using a 116 kW linear electron beam. The scattering measurements are carried out using deposition technique. It is found that about 1% of copper vapor that entered through slit got scattered onto the collector plate. [ABSTRACT FROM AUTHOR]

Zirconium (Zr) plasma is produced by electron-impact ionization during Zr vapor evaporation in an electron beam evaporator. The plasma is embedded in the vapor. It expands along with the vapor in a transverse magnetic field. Parameters like ion density, electron temperature, space potential, floating potential of the plasma were measured by a disc type Langmuir probe. Since Zr metal has high melting point (∼ 2128 K), the evaporator is filled with condensable vapor and remains at high temperature (∼ 700 K). The probe was designed and fabricated in a manner that the insulator was protected from the direct deposition of Zr vapor. The measurement shows that the e-beam generated plasma is weakly ionized (degree of ionization ∼ 0.1 %) and it has low electron temperature (∼ 0.1 eV). It is also observed that the plasma ions have a flow velocity in vertical direction similar to the neutral atoms. [ABSTRACT FROM AUTHOR]

Atomic Vapor Laser Isotope Separation (AVLIS) is an established method of isotope separation for various elements used in the nuclear industry. Real-time knowledge of vapor flux, density and flow velocity of the atomic beam is essential in the AVLIS process to estimate the throughput, ionization yield and laser repetition rate, respectively. Conventional techniques used in EB-PVD and thin film coating do not provide these parameters independently. The microbalance technique, on the contrary, provides atomic flux, flow velocity and atom density simultaneously. In the present work, flux and flow velocity of copper and zirconium atomic beams are measured using the microbalance technique. The atomic beams are generated by electron beam heating using a strip-type electron gun with the electron beam power ranging from 36 kW up to 100 kW corresponding to the temperature ranges of 1740 to 1950 K (Kn=0.73 to 0.08) for copper and 2606 to 3269 K (Kn=20.95 to 0.12) for zirconium. The measurement on copper was carried out as a benchmark as the copper atomic beam has been reported to behave as an ideal monatomic gas due to the absence of any low-lying metastable states of copper. However, the velocity of the copper atomic beam was found to be much higher than that reported earlier. This is explained on the basis of electron impact excitation. For the atomic beam of zirconium, which has two low-lying metastable states, it was observed that the measured velocities approached the maximum velocity due to adiabatic free expansion, but could not attain it. This implicates only partial contributions to the atomic beam velocity from both thermal as well as electron impact excitation as the atom density of zirconium was not high enough even at the highest applied electron beam power. [ABSTRACT FROM AUTHOR]