Search

Importance: Cancer and other noncommunicable diseases (NCDs) are now widely recognized as a threat to global development. The latest United Nations high-level meeting on NCDs reaffirmed this observation and also highlighted the slow progress in meeting the 2011 Political Declaration on the Prevention and Control of Noncommunicable Diseases and the third Sustainable Development Goal. Lack of situational analyses, priority setting, and budgeting have been identified as major obstacles in achieving these goals. All of these have in common that they require information on the local cancer epidemiology. The Global Burden of Disease (GBD) study is uniquely poised to provide these crucial data. Objective: To describe cancer burden for 29 cancer groups in 195 countries from 1990 through 2017 to provide data needed for cancer control planning. Evidence Review: We used the GBD study estimation methods to describe cancer incidence, mortality, years lived with disability, years of life lost, and disability-Adjusted life-years (DALYs). Results are presented at the national level as well as by Socio-demographic Index (SDI), a composite indicator of income, educational attainment, and total fertility rate. We also analyzed the influence of the epidemiological vs the demographic transition on cancer incidence. Findings: In 2017, there were 24.5 million incident cancer cases worldwide (16.8 million without nonmelanoma skin cancer [NMSC]) and 9.6 million cancer deaths. The majority of cancer DALYs came from years of life lost (97%), and only 3% came from years lived with disability. The odds of developing cancer were the lowest in the low SDI quintile (1 in 7) and the highest in the high SDI quintile (1 in 2) for both sexes. In 2017, the most common incident cancers in men were NMSC (4.3 million incident cases); tracheal, bronchus, and lung (TBL) cancer (1.5 million incident cases); and prostate cancer (1.3 million incident cases). The most common causes of cancer deaths and DALYs for men were TBL cancer (1.3 million deaths and 28.4 million DALYs), liver cancer (572000 deaths and 15.2 million DALYs), and stomach cancer (542000 deaths and 12.2 million DALYs). For women in 2017, the most common incident cancers were NMSC (3.3 million incident cases), breast cancer (1.9 million incident cases), and colorectal cancer (819000 incident cases). The leading causes of cancer deaths and DALYs for women were breast cancer (601000 deaths and 17.4 million DALYs), TBL cancer (596000 deaths and 12.6 million DALYs), and colorectal cancer (414000 deaths and 8.3 million DALYs). Conclusions and Relevance: The national epidemiological profiles of cancer burden in the GBD study show large heterogeneities, which are a reflection of different exposures to risk factors, economic settings, lifestyles, and access to care and screening. The GBD study can be used by policy makers and other stakeholders to develop and improve national and local cancer control in order to achieve the global targets and improve equity in cancer care. © 2019 American Medical Association. All rights reserved.

Synopsis After our observation of “quasi-equilibrium” in charge-state evolution for 2.0 MeV/u sulfur ions after carbon foil penetration, we have extended the initial ions to 1.0 and 2.0 MeV/u carbon ions. A significant quasi-equilibrium was observed for 1.0 MeV/u C+C collisions, where the equilibrium mean charge-state was 4.9, while for 2.0 MeV/u C+C collisions, where the equilibrium mean charge-states was 5.6, was a weak quasi-equilibrium.

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.

The aim of this study was to investigate the differences between rats and hamsters, Two of the most widely used experimental animals, with respect to the effects of microsomal membrane solubilization on the inhibition of liver 11β-hydroxysteroid dehydrogenase (11β-HSDI) enzyme by bile acids. Liver microsome fractions were prepared, and the 11β-HSDI enzymatic activity was measured using cortisone as a substrate. The substrate and various concentrations of bile acids were added to the assay mixtures. After incubation, the products were extracted and analyzed using high-performance liquid chromatography. To investigate the effect of detergent on the inhibitory effects of bile acids, we conducted inhibition tests using Triton X-100-solubilized animal liver microsomes. When solubilized microsomes were used, all bile acids inhibited 11β-HSDI from rats and hamsters to various degrees. 7α-Hydroxycholanoic acids (cholic acid and chenodeoxycholic acid) in particular had strong inhibitory activities. In hamsters, 7β-hydroxycholanoic acid (ursodeoxycholic acid) was the strongest inhibitor among the bile acids tested, although its effect was not very strong. When nonsolubilized microsomes were used, deoxycholic acid did not inhibit but rather enhanced the enzymatic activity in both animals. Microsomal content of cholesterol and phospholipids are significantly different between rats and hamsters. Species differences in bile acid inhibition of nonsolubilized microsomes might be reflected not only by structural difference of bile acids, which affect membrane solubilization and enzyme activity directly, but also species difference in microsomal membrane lipid content.

Both equilibrium and non-equilibrium charge-state distributions were studied experimentally for 2.0 MeV/u carbon ions after passing through carbon foils. Measured charge-state distribution established the equilibrium at a target thickness of 10 μg/cm2 and this remained unchanged until a maximum target thickness of 98 μg/cm2. The equilibrium charge-state distribution, the equilibrium mean charge-state, and the width and skewness of the equilibrium distribution were compared with predictions using existing semi-empirical formulae as well as simulation results, including the ETACHA code. It was found that charge-state distributions, mean charge states, and distribution widths for C2+, C3+, and C4+ incident ions merged into quasi-equilibrium values at a target thickness of 5.7 μg/cm2 in the pre-equilibrium region and evolved simultaneously to the ‘real equilibrium’ values for all of the initial charge states, including C5+ and C6+ ions, as previously demonstrated for sulfur projectile ions at the same velocity (Imai et al., 2009). Two kinds of simulation, ETACHA and solution of rate equations taking only single electron transfers into account, were used, and both of them reproduced the measured charge evolution qualitatively. The quasi-equilibrium behavior could be reproduced with the ETACHA code, but not with solution of elementary rate equations.

Energy spectra of electrons ejected through autoionization decay of high-Rydberg states in high-energy collisions of Nq+ (q = 1–3) with He have been measured with high-resolution by using zero-degree electron spectroscopy. Several series of autoionizing lines were observed, corresponding to decays from N3+ 1s22p(2P)nl Rydberg states produced in N3+ + He collisions, from N2+ 1s22s2p(3P)nl Rydberg states produced in N2+ + He and from N+ 1s22s2p2(4P)nl Rydberg states produced in N+ + He, respectively. Angular momentum distributions for the first or second peak of three series of Coster–Kronig electron transitions for Nq+ (q = 1–3) projectiles are also discussed, where the highly excited states are formed by electron excitation.

Charge state distribution and its evolution for 2.0 MeV/u sulfur ions after passing through 0.9, 1.1, 1.5, 2.0, 3.0, 4.7, 6.9 and 10 μg/cm 2 carbon foils have been extensively studied following our previous paper [M. Imai, M. Sataka, K. Kawatsura, K. Takahiro, K. Komaki, H. Shibata, H. Sugai, K. Nishio, Nucl. Instr. and Meth. B 230 (2005) 63] to derive data for all the initial charge states between 6+ and 14+. Measured charge state distributions, their mean charge states and distribution widths do not flat off to establish equilibrium within the measured target thickness, and an overshooting feature of the distribution width for S 6+ projectile is observed around 1 μg/cm 2 in the target thickness. Two kinds of calculations, one based on rate equations accounting only for single charge transfer and the other applying ETACHA code, show good agreements with the experimental evolutions of mean charge and distribution width.

Electrons emitted from high Rydberg states formed by penetration of 2.0 MeV/u Ar6, 13, 14, 15+ ions through C-foil targets of various thicknesses (4.0 - 20 µg/cm2) have been measured with high resolution utilizing zero-degree electron spectroscopy. Intense series of Coster-Kronig peaks due to Ar14+ 1s22p(2P3/2,1/2)nl - 1s22s(2S1/2)el' and Ar13+ 1s22s2p(3P2,1,0)nl - 1s22s2 (1S0)el' transitions, in which the principal quantum number, n, starts at 10 and increases with increasing peak energy, have been observed for every combination of initial charge state and foil thickness, and quite a few number of other peaks remain unassigned in the electron energy region investigated. Intensities of each series of Coster-Kronig electron peaks follow the n-3 law. The mean charge states after the foil penetration have been found to be the same within 10% uncertainty and the total intensity of the Coster-Kronig transitions including Ar15+ 1s22p(2P) and Ar14+ 1s22s2p(3P) cores have also been found to remain constant for all the collision systems investigated. The total Ar15+ 1s22p(2P) population derived from n = 10 transition peaks is found to be almost the same as those of Ar14+ 1s22s2p(3P), which is in contrast to the ratio of Ar15+ to Ar14+ fractions measured downstream the foil.

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.

Time and two-dimensional position distributions of F+ ions emitted from a well-defined F/Si(1 0 0)-2 × 1 target were measured for impact of slow highly charged ions of 3.9 keV Ar5+. The time and position distributions were transformed into energy and angular distributions, which revealed that the peak emission energy was 2.0 ± 0.6 eV and the emission angle measured from the surface normal was 18 ± 4° in the (0 1 1) or ( 01 1 ¯ ) plane.

A new scheme to effectively and quickly cool highly charged ions (HCIs) is presented. The key item is the combination of high density electron plasma and cold positron plasma, which enables to realize a quick cooling (∼1 s) and at the same time the HCI loss due to recombination with electrons and residual gases is largely suppressed.

We measured charge state dependence and incident angle dependence of sputtering yields and two-dimensional (2D) position distributions for H+, Si+ and SiOH+ ions emitted from a water adsorbed Si(1 0 0) surface irradiated by a few keV Arq+ (q = 4–8). It was found that (1) H+ yield strongly depended on the charge state and increased with increasing incident angle, (2) Si+ and SiOH+ yields were independent of the charge state and increased with increasing incident angle.

X-rays emitted from Ar 17+ , Fe 24+ and Kr 35+ ions of about 400 MeV/u transmitting through a thin Si crystal of about 20 μm thickness have been measured in a planar channeling condition and compared with those in a random incident condition. We have found that the X-ray yield from Ar 17+ ions is larger for the channeling condition than for the random incidence, while those from Fe 24+ and Kr 35+ ions are rather smaller. Such tendencies are explained by considering the projectile dependences of excitation and ionization probabilities together with X-ray emission rates. A crude simulation has qualitatively reproduced these experimental results. When the crystal thickness is small, the X-ray yield is smaller in the channeling condition than in the random incident condition, because excitation is depressed. However, for thicker crystals, the X-ray yield is larger, since the survived population of projectile-bound electrons is larger due to small ionization probabilities under the channeling condition. This inversion occurs at a specific crystal thickness depending on projectile species. Whether the thickness of the used crystal is smaller or larger than the inversion thickness determines enhancement or depression of the X-ray yield in the channeling condition.

Charge state distributions of 2.0 MeV/u sulfur ions of various initial charge states (6, 10, 11, 13+) after passing through 0.9, 1.5, 2.0, 3.0, 4.7, 6.9 and 10 μg/cm2 carbon foils have been studied. It is observed that the processes involving the L-shell electrons are equilibrated within the target thickness of ∼5 μg/cm2 and the charge equilibration over this thickness is ruled by the K-shell processes. Measured charge state distributions do not flat off to establish equilibrium within the measured thicknesses, but the mean charge states almost saturate to 12.4 for all initial charge states examined. Calculation with ETACHA code, developed by Rozet et al. [Nucl. Instr. and Meth. B 107 (1996) 67], is employed, although the present impact energy is lower than the assumed region for the code.

Energetic ions traveling through a single crystal are excited by an oscillating crystal field produced by a periodic arrangement of the atomic strings/planes, which is called Resonant Coherent Excitation (RCE). We have observed enhancement of convoy electron yields associated with RCE of 1s electron to the n=2 excited states of 390 MeV/u hydrogen-like Ar17+ ions passing through a Si crystal in the (2 2 0) planar channeling condition. Lost electrons from projectile ions due to ionization contribute to convoy electrons emitted in the forward direction with the same velocity as the projectile ions. With combination of a magnet and a thick Si solid-state detector, we measured the energy spectra of convoy electrons of about 200 keV emitted at 0°. The convoy electron yield as a function of the transition energy, i.e. the resonance profile, has a similar structure to the resonance profile observed through the ionized fraction of the emerging ions. It is explained by the fact that both enhancements are due to increase in the fraction of the excited states from which electrons are more easily ionized by target electron impact in the crystal than from the ground state.

A beam line for the transportation of slow antiprotons from a multiring electrode trap to an experimental chamber is described. The beam line is equipped with a three-stage differential pumping system in order to maintain a pressure lower than 1×10−12 Torr in the trap region while simultaneously having a pressure of around 1×10−6 Torr in the chamber. Tests have shown that 105 positive ions per trapping cycle were successfully extracted at 250 eV from the trap positioned in a superconducting solenoid. The ions were then further transported through three small apertures to the target area located 3.5 m downstream of the trap. Results from the first delivery of a 250 eV antiproton beam are described.

X-rays emitted from resonant coherently excited (RCE) n =2 states of 390 MeV/amu hydrogen-like Ar 17+ ions were observed under planar channeling in a Si crystal. The resonance profiles for X-ray emission consisting of two peaks for j =1/2 and j =3/2 are characterized by suppression of the j =1/2 peak. The degeneracy of the n =2 states are removed by Stark effect due to the static crystal field. The RCE probability of these Stark splitted substates differs, reflecting the polarization of the oscillating crystal field. However, the associated alignment was not clearly observed. It is explained by the fact that both polarization of the oscillating crystal field and the wave functions of Stark-mixed n =2 states depend on the distance from the channel center, and the X-ray emission is preferred in a channel center in a crystal.

Secondary ion emission phenomena from a water and fluorine adsorbed Si(1 0 0) surface irradiated with electrons and highly charged ions (HCIs) were studied. In the case of HCI impact (400 eV/ q Ar q + 4⩽ q ⩽8), H + and F + ions were detected in addition to Si(H) + and SiOH + ions resulted from a kinetic energy transfer. The yields of H + and F + , which were also observed in the case of electron impact, increased with q like q γ ( γ ∼3). This is the first paper reporting a strong charge state dependence of heavy adsorbate yields when slow HCIs bombard a well-defined surface covered with adsorbate.

We have observed photons in the visible light range emitted from slow (2.0 keV/amu) highly charged Ar6+ ions which have captured one electron and transmitted through a Ni microcapillary target. Observed lines were identified by comparing with an ab initio calculation based on the multi-configuration Hartree-Fock method. (C) 2003 Elsevier Science B.V. All rights reserved.

Coster–Kronig (C–K) and Auger electron spectra from highly excited states produced by high-energy highly charged ions with a He target have been investigated using zero-degree electron spectroscopy. C–K and Auger electrons produced in 32 MeV Oq+ (q=3,4)+He collisions were measured, where the highly excited states of three-, four- and five-electron O ions were formed by electron excitation/ionization. It is found that the 1s22pnl states with relatively low angular momenta are excited in the O4+ ion collisions while the 1s22s2pnl states with higher angular momenta are excited in the O3+ ion collisions. K Auger spectra produced in Oq+ (q=3,4)+He collisions qualitatively agree with the previously measured results.

A system consisting of a superconducting solenoid, a multi-ring trap and a slow positron source has been built to prepare a cold highly charged ion (HCI) beam, which will be applied to study interactions with solids or gases, e.g. potential energy deposition scheme during interaction of slow HCIs with a surface. An electron plasma with density more than 1010 cm−3 has already been prepared to trap positrons.

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.

The resonant coherent excitation from a 1s state to n=2 states of 94 MeV/u Ar17+ ions channeling in the (2 2 0) plane of a Si crystal was observed as the decrease of the survival fraction of Ar17+. Three resonance dips of survival fraction were clearly seen. The resonance profile is attributed to the spin–orbital interaction, the position-dependent Stark effect, the position-dependent transition probability and the position-dependent ionization probability of excited states. The estimated experimental resolution of measurement of the resonance profile is comparable to the width of the narrowest resonance dip (∼1.5 eV FWHM) or less.

A potential sputtering mechanism of hydrogen has been studied for impacts of slow highly charged Xe q + ions ( q =4–12) on well-defined H-terminated and water-saturated Si(1 0 0) surfaces. It was found that the sputtering yields of protons were proportional to q γ ( γ ∼5) for both the Si(1 0 0)2×1-H and Si(1 0 0)1×1-H surfaces, although the absolute yield for the Si(1 0 0)1×1-H surface was 10 times larger than that for the Si(1 0 0)2×1-H surface, i.e. the sputtering efficiency per one H–Si bond for the Si(1 0 0)1×1-H surface is five times larger that for the Si(1 0 0)2×1-H surface. The proton sputtering efficiency from a H–O–Si bond was extracted from measurements of the water-saturated surface, which was ∼8 times larger than the H–Si bond of the Si(1 0 0)2×1-H surface. An effective distance of the proton from its substrate was proposed to be the key parameter to govern the yield, which also influences the energy distributions of sputtered protons. These findings are consistently explained with a pair-wise bond-breaking model induced by a double electron capture, where the classical over barrier process plays an essential role.

Proton sputtering from H-terminated Si(1 0 0) surfaces bombarded with Xeq+ (q=4–12, E=2–5 keV) were experimentally studied. Proton sputtering yields and two-dimensional (2D) distribution of protons were measured employing a time-of-flight technique with a 2D position sensitive detector. It was found that the q dependence of the proton sputtering yield from Si(1 0 0)–(2×1)H surface with Xeq+ was the same (∼q5) as that from an untreated surface, although the absolute yield was about 1/30. The yield from Si(1 0 0)–(1×1)H surface was about 10 times larger than that from the Si(1 0 0)–(2×1)H surface. The mean energy of emitted protons from Si(1 0 0)–(2×1)H and Si(1 0 0)–(1×1)H surfaces were 1.2 and 5.9 eV, respectively.

X-rays emitted from 2.3 keV/u 15 N 7þ ions transmitted through a highly ordered Ni microcapillary were measured with a high-resolution soft X-ray spectrometer. The highly ordered microcapillary has recently become available employing a nano-lithographic technique. A transmission ratio and charge state distribution of ions through the microcapillary target were found to be consistent with theoretical predictions. A preliminary analysis showed that a series of X-rays from np–1s transitions with n as high as 8 were identified,which is consistent with the classical over barrier model. 2002 Elsevier Science B.V. All rights reserved.

Spectra for Coster–Kronig (C–K) transition 1s 2 2pð 2 P3=2Þ9l ! 1s 2 2sð 2 S1=2Þel 0 of Be-like S 12þ ions produced following penetration of 2.5 MeV/u S qþ ions (q ¼ 7, 10, 12, 13) through C-foil targets of various thickness (1–6.9 lg/cm 2 ) have been probed using zero-degree electron spectroscopy. It has been found that in collisions for S qþ (q ¼ 7, 10) ion incidence, in which the C–K electrons originate from the projectile bound electrons, a fraction of the angular momentum l ¼ 1 of the Rydberg state decreases, and fractions of higher ðl P 2Þ angular momenta increase, while the total intensity of the C–K electrons grows, as target foil thickness increases. The electron spectra for S qþ (q ¼ 13) incident ions, in which the autoionizing Be-like state is preferably formed by electron capture from the target continuum upon or near the exiting surface, do not change in l-distribution or intensity. The shift to higher l comes from the multiple collisions of electron with the target, in traveling at the same speed under the strong Coulomb potential of the projectile. The observed dependence of the l-distribution and the intensity of the Rydberg state on projectile initial charge and target thickness indicates the importance of transport phenomena for both the S 13þ core and the projectile-entrained electrons inside solid. 2002 Elsevier Science B.V. All rights reserved.

We measured the emerging charge-state distribution of hydrogen-like 390 MeV/u Ar 17þ ions planar channeled in a silicon surface barrier detector for the DE measurement, and observed their energy deposition in the detector simultaneously. We simulated the energy loss spectrum of specific emerging charge state, and succeeded in reproducing it with an adjusting parameter for the cut-off momentum transfer between close and distant collisions. 2002 Elsevier Science B.V. All rights reserved.

Several peaks have been observed, in the electron energy range up to 20 eV, due to Coster-Kronig electrons from the autoionizing Rydberg states emitted from 2 MeV u-1 Si5+ ions excited through a carbon foil. To obtain a better understanding of these low-energy electron spectra and their production mechanisms, we synthesize the expected electron spectrum which is compared with the observed electron spectrum. Two theoretical methods, namely the perturbation theory of Z-expansion (MZ code) and the multiconfiguration Hartree-Fock method (Cowan code), are used to calculate the necessary Auger electron energies and emission rates. It has been found that the 1s22pnl-1s22s 2S and 1s22s2pnl-1s22s2 1S decays give the most significant contributions to the observed electron spectrum from threshold up to the 20 eV region. The synthetic electron spectra have also been found to reproduce the observed electron spectra quite nicely when the charge distributions of the projectile Si ions after thin carbon foils are taken into account.

The formation and relaxation processes of hollow atoms and related excited states of ions produced with a Ni microcapillary thin foil have been studied employing various experimental techniques. The first stage of the charge transfer from the surface to the ions was studied by using visible light measurements. On the other hand, X-ray measurements revealed the core electronic configurations of ions at the last moment of the hollow atom evolution. The overall feature of the electron capture processes in the capillary was given by the charge state distribution measurements.

We have succeeded in observing resonant coherent excitaion (RCE) of 1s electrons to the n = 3 states in 390 MeV/u hydrogen-like Ar17+ ions planar channeled in a silicon crystal through measurements of the charge-state distribution of ions transmitting the crystal. Furthermore, we directly confirmed RCE to the n = 3 states by observing the enhancement of the de-excitation X-rays, i.e., Kβ X-rays under the resonance condition. The resonance profiles of the charge-state distribution as functions of the incident angle to the crystal, which uniquely relates with the transition energy, have a characteristic structure consisting of several peaks. Compared with the profile of RCE to the n = 2 states, the present profiles show a large peak shift from the j = 1/2 and 3/2 levels in vacuum, and the profiles are much wider than those expected from the Stark-split level structure of the n = 3 manifolds due to the position- (distance from the channel center in the planar channel) dependent strong static field in the crystal.

Resonant coherent excitation (RCE) of 390 MeV/u hydrogen-like Ar 17a ions planar channeled in a Si crystal was investigated through measurements of the de-excitation X-rays as well as the charge state distribution of the transmitted ions. We observed enhancements of both the fraction of ionized Ar 18a ions and the intensity of the de-excitation X-rays under the RCE condition. The na 2 states of Ar 17a in the crystal are split into four energy levels due to spin‐orbit interaction and Stark eAect induced by the planar potential of the crystal. The intensities of the X-rays from the lower two levels were found to be smaller compared with those from the higher two levels, which is explained by the dominance of the 2s component not decaying via a single photon emission. The diAerence between the resonance profiles of the charge state and the X-ray reflects the nature of na 2 states in the crystal field. ” 2000 Elsevier Science B.V. All rights reserved.

ions has been observed through measurements of the surviving charge state of Arions planar channeled in a Si crystal. We experimentally demonstrate trajectory-dependent, i.e., impactparameter dependent resonant-coherent-excitation phenomena by measuring the energy deposition incoincidence with the charge state of emerging ions. The resonant-coherent-excitation transition energyreflects spin-orbit

Resonant coherent excitation of the 1s electron to na 2 states in a hydrogen-like ion was studied through measurements of the survived fraction of 390 MeV/u Ar 17a planar channeled in a Si crystal. Adopting a totally depleted Si surface barrier detector as a target crystal, the charge state of the individual emerged ion was measured in coincidence with the energy deposition in the target. By changing the incident direction along theO2 20 U ,O 004 U, andO1 11 Uplanes, a series of clear resonances were observed as the decrease in the survived charge fraction due to higher electron loss probability for the excited state. Each resonance profile reflects energy splitting of the na 2 manifold originated from l‐ s interaction and Stark eAect due to the crystal field. From the correlation between the energy loss and survived charge fraction, transition energy as a function of the ion trajectory amplitude is deduced which is in good agreement with calculated results. ” 1998 Elsevier Science B.V. All rights reserved.

Continuum X-rays emitted from Be- and C-targets bombarded with 75-290 MeV/u C6+ ions were observed with an HPGe detector placed at 90\(\) to the beam direction. In all spectra two components could be clearly distinguished: Radiative Electron Capture into Continuum (RECC) forming a characteristic edge, and Secondary Electron Bremsstrahlung (SEB) which dominates at high photon energies. The shape of the spectra was compared to a theoretical description. A special emphasis was given to the details of the RECC edge. It has been found that at the highest projectile energy of 290 MeV/u, in opposite to the lower beam energies, the detailed structure of this edge cannot be reproduced satisfactory within the approach applied.

We have succeeded in observing the channeling of 290 MeV/u C 6+ ions in a Si crystal. Under 〈1 1 0〉 axial, and (0 0 4), (2 2 0) and (1 1 1) planar channeling conditions, energy loss of the channeled ion in the Si crystal was observed. We also calculated the trajectory dependent stopping power for planar channeling ions, which employs mean and local electron densities evaluated adopting the Moliere potential. Calculated energy loss spectra were found to reproduce the experimental results quite well.

We observed resonant coherent excitation (RCE) of 1s electron to n=2 states in Ar17+ through measurements of the survived fraction of 390 MeV/u hydrogen-like Ar17+ channeled in a Si crystal. We adopted a totally depleted Si surface barrier detector as a target crystal as well as a probe of the energy deposition. The charge state of emerged ions was measured by a combination of a charge separation magnet and a 2D-position sensitive detector. We observed the RCE for planar channeled ions by tilting the target Si crystal from the direction of [1 1 0] axis in the (2 2 0) , (0 0 4) , and (1 1 1) planes. Prominent resonances at tilt angles under the resonance condition were observed. Moreover, each resonance profile is split into several lines due to the l·s interaction and the Stark effect originating in the static crystal field. The energy deposition in the crystal gives the information of the amplitude of the ion trajectory. The resonance peak position, intensity and width in the survived fraction of Ar17+ reflect the position dependent strength of the crystal field, the RCE and the electron loss probabilities. They are in good accord with our calculation of the transition energy and probability.

Swift heavy ions channeled in a crystal experience a variety of atomic processes which depend on the ion trajectory in the channel. Recent studies on the atomic processes such as slowing down of the ion, charge changing collision, excitation of bound electrons, and so on in connection with ion trajectories or impact parameter are reviewed. Resonant coherent excitation (RCE) is a composition of various atomic processes and has offered a new field in atomic physics and has been investigated experimentally and theoretically. Recent progress in this field is also reviewed.

Soft X-rays were measured in collision of 1‐3 keV/u Ar qa (qa 2‐14) ions on an amorphous C target. Ar L X-rays due to initial L-shell holes were successfully decomposed. It was found that L-shell vacancies of Ar were filled stepwise primarily via 3s‐2p transition for each step. ” 1998 Elsevier Science B.V.

High-resolution Coster–Kronig (C–K) electron emission spectra in collisions of 32 MeV O 3+ ions with a He gas target have been investigated using zero-degree electron spectroscopy. Zero-degree electron spectrum for the O 3+ projectiles exhibits a trident-like structure around the cusp peak, consisting of three clear peaks. The sharp peaks directly on either side of the cusp corresponded to autoionization lines from highly excited O 3+ ions produced in the collision with a He gas target, which are confirmed to be due to the configuration 1s 2 2s2p( 3 P)5s, where the C–K ejection energy is 0.014 eV. The C–K transitions in higher energy region are found to originate in 1s 2 2s2p( 3 P) nl –1s 2 2s 2 el ′ ( n = 5–11). For n = 5–7, a clear angular momentum distribution is observed, where the maximum intensity is attributed to the relatively high angular momentum l = 2 or 3.

K x rays emitted from 2.1 keV/uN{sup 6+} ions passed through a thin Ni microcapillary foil were measured in coincidence with the exit charge states. Ions with a K hole but with several electrons in outershells, i.e., hollow ions formed above a surface (in the first generation), were successfully extracted in vacuum. It was found that a considerable fraction of extracted hollow ions had extremely long lifetimes of the order of ns. {copyright} {ital 1997} {ital The American Physical Society}

Zero-degree electron spectra were measured with high resolution for 64 MeV Sq+ (q = 6, 11 to 13) ions on a He and C-foil target. Several peaks are observed in the electron energy range up to 2.5 eV for the 64 MeV S12+ + He collision, in addition to a series of autoionization electrons produced by the Coster-Kronig transition 1 s 2 2p( 2 P 3 2 )9l−1 s 2 2s ϵl′ . The charge state dependence of electron spectra for 64 MeV S11+.12+.13+ + He and S6+.12+.13+ + C were measured to identify the origin of the low energy electrons. No characteristic line is observed in the electron energy spectra following the 64 MeV S13+ beam excitation with He. This indicates that the electron excitation and capture process that could produce the Li- and Be-like initial configurations resulting in autoionizing Coster-Kronig transitions does not occur during a collision between 64 MeV S13+ ions and a He target at this collision energy. It is supposed that the electron spectra for S11+ shows a series of autoionizing Coster-Kronig transitions of 1s22p27l−1s22s2pϵl′, 1s22p29l−1s22s2pϵl′ and 1s22s2p9l−1s22s2ϵl′ for S11+ ions, which are energetically possible.

Continuum x rays originated from radiative electron capture into continuum states (RECC) of relativistic Ne{sup 10+} ions have been observed. It has been found that the intensities of x rays decrease as their energy increases and the observed spectra show a clear edge which corresponds to the maximum energy transferred to free electrons under energetic projectile-ion collisions. The edge becomes dramatically sharp as the incident projectile energy decreases from 290 to 75 MeV/amu, indicating that the cross sections for RECC sharply increase at low projectile energies, which is in agreement with the theoretical expectation. {copyright} {ital 1997} {ital The American Physical Society}

Two theoretical methods, namely perturbation theory of Z-expansion (MZ code) and multi-configurational Hartree-Fock methods (Cowan code), were used for identification of Coster-Kronig (CK) electron spectra from the singlet and triplet 1s22p9l states of S12+. The correlation effects are discussed through comparison between two methods. Transition energies have also been calculated for CK electron energy from 1s22pnl (n = 10–20) states.