Accurate data for dielectronic recombination of tungsten ions are essential in the modeling of tungsten impurity transport and radiative power loss in International Thermonuclear Experimental Reactor(ITER).Theoretical calculations have been made for dielectronic recombination(DR)rate coefficients of Br-like tungsten ions using a flexible relativistic atomic code(FAC)from 1 eV to 50 keV.Level-by-level calculations are carried out for evaluating the contributions to DR through all the relevant Kr-like tungsten ions autoionizing inner-shell excited configuration complexes:(3s^23p^63d^(10))^(-1)4s^24p^5nln'l'(n=4-5,n'=4-100,1'=0-8),(4s^24p^5)^(-1)nln'l'(n=4-6,n'=4-100,l'=0-12).Comparison of the rate coefficients for 3s,3p,3d,4s and 4p subshell excitations shows that the 4p subshell excitation dominates over the whole temperature region,4s subshell excitation at low temperature and 3p,3d subshell excitations at high temperature can not be neglected.In order to facilitate simple applications,the total DR rate coefficient,△n=0,1 and 2 core excitations DR rate coefficients are fitted to an empirical formula.
Two Q-switched Nd:YAG lasers at 1064 nm wavelength have been employed to produce plasmas on aluminum-based alloy in single- and collinear double-pulse laser induced breakdown spectroscopy(LIBS).Time resolved technique was used for detecting emission signal by spectrometer equipped with ICCD detector.The intensity calibration of spectral response was performed by using deuterium and tungsten halogen lamps.Time evolution of the plasma temperature and electron number density was investigated in single- and collinear double-pulse experiments.Based on the investigation of plasma parameters,the emission signal enhancement mechanism was discussed qualitatively.
The transition energies and electric dipole(E1)transition rates of the K,L,and M lines in neutral Np have been theoretically determined from the MultiConfiguration Dirac–Fock(MCDF)method.In the calculations,the contributions from Breit interaction and quantum electrodynamics(QED)effects(vacuum polarization and self-energy),as well as nuclear finite mass and volume effects,are taken into account.The calculated transition energies and rates are found to be in good agreement with other experimental and theoretical results.The accuracy of the results is estimated and discussed.Furthermore,we calculated the transition energies of the same lines radiating from the decaying transitions of the K-,L-,and M-shell hole states of Np ions with the charge states Np1+to Np6+for the first time.We found that for a specific line,the corresponding transition energies relating to all the Np ions are almost the same;it means the outermost electrons have a very small influence on the inner-shell transition processes.
