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We measured resonant coherent excitation of a 2s electron of 83.3 MeV/u Fe 23+ ions planar-channeling in the ( 2 ¯ 2 0 ) plane of the silicon crystal. A silicon surface barrier detector (SSD) was used as a crystal target in order to obtain information on the ion trajectory in the channel since the energy deposit ( Δ E ) to the SSD gives information on the ion trajectories where the resonant transitions occur. For the low Δ E , i.e., near the channel center, optically allowed 2s–3p transitions were much stronger compared with other transitions. Increasing Δ E , i.e., increasing the amplitude of ion trajectory, the optically forbidden 2s–3s transition rapidly became strong. On the other hand, the optically forbidden 2s–3d transitions did not become strong as rapidly as 2s–3s transition. Furthermore, it was found that the transition energies to the n = 3 states changed with Δ E . The shifts of the transition energies were consistent with the estimation for the energy levels of the Stark-mixed n = 3 states depending on the distance from the channel center.

K X-rays emitted from 2.1 keV/u N ions transmitted through a thin Ni microcapillary foil were measured in coincidence with a final charge state qf, using a Si(Li) X-ray detector in the cases of incident charge states of qi = 7 and 6. It was found that (1) the coincidence X-ray yield for (qi, qf) = (7, 6) decreased faster than those for other (qi, qf) combinations, (2) the coincidence X-ray yields did not depend on the number of K-shell holes of the incident ions but on the final charge state qf.

Multiple ionization processes of argon atoms by a linearly polarized laser light with the maximum peak intensity of about 5 × 1015 W cm−2 were investigated by the recoil-ion momentum spectroscopy. Momentum distributions of argon ions with charge states 3+ and 4+ were measured. The experimental results were compared with calculations based on the sequential ionization model and the ADK ionization rate [M.V. Ammosov et al., Zh. Eksp. Teor. Fiz. 91 (1986) 2008 (Sov. Phys. JETP 64 (1986) 1191)]. The calculated widths of the distributions agreed with the experimental results to within 30%.

We have made coincidence measurements between L X-rays and final charge states of highly-charged Ar ions passing through a Ni microcapillary thin foil to study the formation and relaxation processes of hollow atoms. By using N6+ projectile ions which have single K-shell hole, Ninomiya et al. [Phys. Rev. Lett. 78 (1997) 4557] showed the existence of long lived excited states formed by multiple electron transfer from a Ni microcapillary thin foil. To further study the formation and relaxation dynamics, such experiments were extended to Ar ions with multiple L-shell holes. The yields of L X-rays from Ar ions, which have one stabilized-electron, decrease faster than those from ions with multiple stabilized-electrons, when the projectiles have multiple inner shell holes.

To detect weak X-rays with a high-resolution spectrometer, a charge-coupled device was operated in a single X-ray photon detection mode. A procedure to effectively identify single X-ray was established. In the case of 2.3 keV/u N7+ and Ne9+ incidence, X-rays emitted from ions transmitted through a Ni microcapillary target were measured with the spectrometer using the procedure of the single event mode. The signal-to-noise ratio was improved by using the single photon counting method.

Ultrasonic signals of near-MHz frequencies were observed when solid targets of Al2O3, KCl and metallic aluminum were irradiated with fast heavy-ions. The projectile beam of 26 MeV/u Xe ions were chopped to pulses shorter than 1 ls. Two piezoelectric sensors detected the acoustic signals at the both ends of the target. The signals were analyzed by Fourier transform and several peaks were observed in the frequency range from several hundred kHz. Amplitudes of the frequency components were nearly proportional to the number of the ions in the pulse. ” 2000 Elsevier Science B.V. All rights reserved.

We have used the technique of beam-foil spectroscopy to investigate transition probabilities for Na-like Nb 30+ and Mg-like Nb 29+ . In the former case the lifetimes of the 3 p 2 P 1 2 , 3 2 levels were determined using the ANDC method of cascade correction. For the Mg-like ion we have studied the decay of the 3s3p 3 P 1 level which gives rise to a spin-forbidden transition to the 3s 2 1 S 0 ground term.

Electrons emitted from projectile ions were measured with high resolution in collisions of 64 MeV S 12+ ions with He atoms and C foils by 0° electron spectroscopy. A series of intense lines have been observed, which are attributed to the Coster-Kronig transitions of 1s 2 2p nl -1s 2 2sϵ l' with n = 9 to 19. The angular-momentum ( l ) distribution of ions in the autoionizing states of n = 9 has been obtained and evidence for high l enhancement has been found in C-foil targets.

The radiation effect on the lattice structure of single-crystal austemtic stainless steel SUS310S under He ion bombardment was studied. The He+ ions, with an energy of 1.7 MeV, were incident along the 〈100〉, 〈110〉 or 〈111〉 axes of the specimen. constituent elements induced by He ions as well as Rutherford-backscattered He ions were measured. The lattice location of the alloying and impurity atoms, and their disordering caused by the He irradiation were investigated. It was shown that aligned X-ray yields in the angular scans increase with the irradiation dose except for P atoms, and the degree of the increase depends very much on the crystallographic orientation and the constituent elements. Some of the impurity P atoms were found to be situated at the body-centered site of the fcc crystal and to be displaced from this site under He ion irradiation.

Projectile Kα satellite and hypersatellite X-ray yields are measured in collisions of Ar ions with energies of 43–95 MeV with solid targets, ZT = 6–74. These high resolution X-ray measurements are analyzed using a statistical model with theoretical fluorescence yields to obtain the average probability of ionization of 2s and 2p subshells. Comparison of the measured relative intensities of Kα satellites with the best theoretical fits are presented.

Analytic formulas are given for the total cross sections, σ, for the charge transfer in collisions of H + , H − and H with metal vapors. The cross sections considered are σ 10 , σ 0−1 , σ 1−1 , σ 01 , σ −10 , and σ −11 , where the subscripts represent the initial and the final charge state of the projectile. The functional form of the formulas is a modification of the semiempirical formula proposed by Green and McNeal for σ 10 of H + in gaseous atoms and molecules. Values of adjustable parameters in the formulas have been determined by least-squares fits to a compiled set of experimental data. The root-mean-square deviation of the data from the formula is from 7 to 34% for each type of cross section. The main cause of larger deviations is the discrepancy among the data.