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The original studies were undertaken to study the feasibility of radiation-induced cataphoretic separation. This part of the work is concerned with laser-induced cataphoretic separation in neon using a He-Ne 6328A laser. The basic...
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The original studies were undertaken to study the feasibility of radiation-induced cataphoretic separation. This part of the work is concerned with laser-induced cataphoretic separation in neon using a He-Ne 6328A laser. The basic concept of radiation-induced caphoretic isotope separation is based on the preferential excitation of one isotope with the result that one isotope is more readily ionized, and relatively more of its ions move toward the cathode in the dc discharge. For the later part of the work a second radiation source was added, a helical Ne exp 20 radiation lamp. Radiation-induced cataphoretic isotope separation has not been observed. Selective excitation has been achieved by both the He-Ne exp 20 6328A laser and the Ne exp 20 helical radiation lamp in spite of the fact that the isotope shift is comprable with Doppler-broadened linewidths. Collisional excitation exchange between the Ne exp 20 and Ne exp 22 atoms does not appear to be a problem for the neon partial pressure range involved. The population of the 3S sub 2 and 2p sub 4 laser levels (6328A) are apparently too low to offer reasonable expectation of inducing observable cataphoretic isotope separation by means of the 6328A laser radiation, even with the high detection sensitivity of the scanning Fabry-Perot spectrometer system. The use of the additional radiation source in the form of a helical Ne exp 20 radiation lamp has not improved the effectiveness of the laser 6328A laser. It has become clear from these experiments, however, that for isotope separation in neon it is well to concentrate on using radiation sources that interact mainly with the ls population.
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Light emission from excited neutral scattered Ne and sputtered Ni were investigated using the LEIS method. A 5-keV Ne sup + beam was used to bombard a Ni(110) surface. Results of the light emission data is presented and compared w...
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Light emission from excited neutral scattered Ne and sputtered Ni were investigated using the LEIS method. A 5-keV Ne sup + beam was used to bombard a Ni(110) surface. Results of the light emission data is presented and compared with neutral production of Ne. 4 refs., 3 figs. (ERA citation 11:036950)
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The studies on radiation-induced cataphoretic isotope separation has been associated with the use of a 0.63- mu He:Ne laser as the radiation source in an attempt to obtain separation of exp 20 Ne and exp 22 Ne isotopes. A cataphor...
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The studies on radiation-induced cataphoretic isotope separation has been associated with the use of a 0.63- mu He:Ne laser as the radiation source in an attempt to obtain separation of exp 20 Ne and exp 22 Ne isotopes. A cataphoretic discharge tube containing mixed neon isotopes is within the laser resonator, whereas the laser tube contains only one neon isotope. Cataphoretic separation of the neon isotopes has not been observed, although selective excitation of one isotope has been demonstrated and a very sensitive technique for detecting cataphoretic isotope separation has been developed. Also, it is found that the exchange rate between the two neon isotopes in the excited laser levels is not great enough to significantly reduce the effect of selective excitation. Measurements of the current changes induced by the radiation indicate that the populations of those levels with which the laser radiation interacts is too small. (ERA citation 04:052723)
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Review of Next Century Corporations participation in the XDATA program, and the progress toward the final state of its software deliverable, Neon and Neon GTD.
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The neutron capture cross sections of the three stable neon isotopes have been measured by the time-of-flight method in the energy range from 5 to 200 keV, using hydrogen free fast liquid scintillator detectors and the Maier-Leibn...
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The neutron capture cross sections of the three stable neon isotopes have been measured by the time-of-flight method in the energy range from 5 to 200 keV, using hydrogen free fast liquid scintillator detectors and the Maier-Leibnitz pulse height weighting technique. As a result it was found that neutron absorption by the light elements, from exp 20 Ne to exp 56 Fe, is dominated not by exp 22 Ne but by exp 25 Mg. The condition that as many neutrons should be produced as are absorbed has led to the conclusion that at least 80% of the exp 22 Ne must undergo the ( alpha ,n) reaction, which implies that less than 20% can undergo the ( alpha , gamma ) reaction. Therefore the ( alpha ,n) reaction rate must be at least 4 times faster than the ( alpha , gamma ) rate. An inspection of these reaction rates as a function of temperature shows that this condition can be satisfied only for T > 3.2 10 exp 8 K, or kT > 28 keV. (ERA citation 08:034807)
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The exp 14 N + exp 10 B fusion reactions were studied at c.m. energies between 2.9 and 7.5 MeV by measuring the yields of gamma -rays from the residual nuclei formed by particle evaporation from the compound system. Cross sections...
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The exp 14 N + exp 10 B fusion reactions were studied at c.m. energies between 2.9 and 7.5 MeV by measuring the yields of gamma -rays from the residual nuclei formed by particle evaporation from the compound system. Cross sections for formation of the evaporation residues exp 16 O, exp 19 F, exp 19 Ne, exp 20 Ne, exp 21 Ne, exp 22 Ne, exp 22 Na, exp 23 Na and exp 23 Mg, as well as the total cross section, were deduced from these yields with the aid of statistical model calculations. exp 14 N + exp 10 B elastic scattering differential cross sections were measured from 4.3 to 9.1 MeV at THETA 74.4 degrees, and from 3.3 to 8.3 MeV at THETA = 90.0 degrees. The elastic scattering cross sections were analyzed within the framework of the incoming-wave boundary condition (IWBC) model. The fusion cross sections calculated for the real ion-ion potential deduced from the IWBC model fit to the elastic scattering are in good agreement with the measured values. (Atomindex citation 12:603988)
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The superconfiguration (SC) approach to collisional-radiative modeling can significantly decrease the computational demands of finding non-LTE level populations in complex systems. However, it has not yet been fully determined whe...
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The superconfiguration (SC) approach to collisional-radiative modeling can significantly decrease the computational demands of finding non-LTE level populations in complex systems. However, it has not yet been fully determined whether the statistical averaging of SC models leads to a significant loss of accuracy. The present work compares results from two independent models: a detailed-level accounting (DLA) model based on HULLAC data and the SC model MOST. The relatively simple level structures of the K- and L-shell ions of the neon test system ensure a tractable number of levels in the DLA model but challenge the statistical assumptions of the SC approach. Nonetheless, we find fair agreement between the two models for average ion charges, SC populations, and various effective temperatures.
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High quality data for the (d, exp 6 Li) reaction on the target nuclei ( exp 24 Mg, exp 25 Mg, exp 26 Mg, exp 27 Al and exp 28 Si) have been obtained at a bombarding energy of 55 MeV. Angular distributions for in total about 200 tr...
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High quality data for the (d, exp 6 Li) reaction on the target nuclei ( exp 24 Mg, exp 25 Mg, exp 26 Mg, exp 27 Al and exp 28 Si) have been obtained at a bombarding energy of 55 MeV. Angular distributions for in total about 200 transitions have been obtained for the five target nuclei studied and for laboratory angles between 10 exp 0 and 37 exp 0 . All cross-sections observed were smaller than 30 mu b/sr, and for most of the transitions on the order of 1 mu b/sr. The angular distributions display a very different behavior for different values of the transferred angular momentum. Transitions to states with known spins and parities have been analyzed in the framework of the DWBA, with the assumption of direct alpha -cluster pick-up. 'Zero-range' (ZR) as well as 'finite-range' (FR) calculations have been performed. Relative alpha -spectroscopic factors have been extracted by means of this analysis and have been compared to the predictions of the SU(3) model and the shell model. Some attention has been paid to the importance of other than direct cluster pick-up reaction mechanisms, in particular to the importance of two-step processes in which the transfer of a cluster is followed by inelastic excitation of the residual nucleus. (Atomindex citation 11:507605)
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