共查询到20条相似文献,搜索用时 9 毫秒
1.
G. Maero F. Herfurth H.-J. Kluge S. Schwarz G. Zwicknagel 《Applied physics. B, Lasers and optics》2012,107(4):1087-1096
The investigation of simple atomic systems in extreme electromagnetic fields with highest precision demands intense beams of heavy and highly charged ions to be decelerated and cooled to extremely low energies for long-time observation. Resistive cooling, i.e., the electronic dissipation of energy of a stored ion cloud on an external impedance, seems to be a good candidate for in-trap cooling of highly charged ions and has been chosen for the upcoming HITRAP (Highly charged Ion TRAP) facility at GSI, Darmstadt. Nevertheless, resistive cooling of large ensembles of ions confined in a Penning trap has never been thoroughly studied until now and the understanding of this highly nonlinear phenomenon is far from complete. Through the use of systematic simulations we give a proof of the feasibility of resistive cooling of large numbers of highly charged ions as well as the interpretation of some specific features observed experimentally. 相似文献
2.
Elmar Träbert 《Hyperfine Interactions》2006,173(1-3):13-18
For spectroscopy, the electron beam ion trap (EBIT) is of special interest, because it provides a cloud of highly charged
ions that is confined to a small volume, at very low particle density, at a relatively low temperature, and without any net
velocity in the laboratory rest frame. These conditions are favourable for observations at high spectral resolution and wavelength
accuracy. Examples from recent work at Livermore comprise extreme ultraviolet and soft-X-ray spectra. A time-resolving multi-pixel
microcalorimeter furthermore permits the study of time-dependent plasma phenomena and atomic lifetimes. Lifetime measurements
at a heavy-ion storage ring can be combined with EBIT measurements to clarify isoelectronic behaviour. 相似文献
3.
Projectile deexcitation Lyman x-ray emission following electron capture and K excitation has been studied in collisions of bare and Li-like sulphur ions (of energy 110 MeV) with fullerenes (C(60)/C(70)) and different gaseous targets. The intensity ratios of different Lyman x-ray lines in collisions with fullerenes are found to be substantially lower than those for the gas targets, both for capture and excitation. This has been explained in terms of a model based on "solidlike" effect, namely, wakefield induced stark mixing of the excited states populated via electron capture or K excitation: a collective phenomenon of plasmon excitation in the fullerenes under the influence of heavy, highly charged ions. 相似文献
4.
Epp SW López-Urrutia JR Brenner G Mäckel V Mokler PH Treusch R Kuhlmann M Yurkov MV Feldhaus J Schneider JR Wellhöfer M Martins M Wurth W Ullrich J 《Physical review letters》2007,98(18):183001
In a proof-of-principle experiment, we demonstrate high-resolution resonant laser excitation in the soft x-ray region at 48.6 eV of the 2 (2)S(1/2) to 2 (2)P(1/2) transition of Li-like Fe23+ ions trapped in an electron beam ion trap by using ultrabrilliant light from Free Electron Laser in Hamburg (FLASH). High precision spectroscopic studies of highly charged ions at this and upcoming x-ray lasers with an expected accuracy gain up to a factor of a thousand, become possible with our technique, thus potentially yielding fundamental insights, e.g., into basic aspects of QED. 相似文献
5.
Ionization and single electron capture in collision of highly charged Ar16+ ions with helium
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This paper uses the two-centre atomic orbital close-coupling method to study the ionization and the single electron capture in collision of highly charged Ar^16+ ions with He atoms in the velocity range of 1.2-1.9 a.u.. The relative importance of single ionization (SI) to single capture (SC) is explored. The comparison between the calculation and experimental data shows that the SI/SC cross section ratios from this work are in good agreement with experimental data. The total single electron ionization cross sections and the total single electron capture cross sections are also given for this collision. The investigation of the partial electron capture cross section shows a general tendency of capture to larger n and l with increasing velocity from 1.2 to 1.9 a.u.. 相似文献
6.
7.
《Physics letters. A》1986,114(2):81-83
Conservation of the initial electronic configuration of singly charged ions in state-selective single electron capture from Li(2s) has been investigated. For impact of O+, N+ and C+ (2–20 keV) it could be demonstrated within the experimental errors, that “core conservation” holds for population of the most probable final states. 相似文献
8.
9.
T. Schwarz R. Jertz J. Stein I. Bergström H. Borgenstrand C. Carlberg G. Rouleau R. Schuch F. Söderberg G. Bollen H. -J. Kluge R. Mann 《Hyperfine Interactions》1996,99(1):83-89
In the SMILETRAP facility externally produced highly charged ions are captured in a Penning trap and utilized for high precision measurements of atomic masses. Accuracy tests on a ppb level have been performed, using highly charged carbon, oxygen and neon ions. In all cases hydrogen ions served as a reference for the calibration and monitoring of the magnetic field in the trap. Deviations smaller than 3 ppb from the expected results were found in mass measurements of the16O and20Ne atomic masses. The proton atomic mass, determined from the reference measurements on hydrogen ions, is in good agreement with the accepted value [1]. A direct mass measurement on the86Kr-isotope, using trapped86Kr29+-ions is reported. 相似文献
10.
H. Häffner N. Hermanspahn P. Indelicato H. J. Kluge E. Lindroth V. Natarajan W. Quint S. Stahl J. Verdú G. Werth 《Hyperfine Interactions》2000,127(1-4):271-276
The mass of a highly charged ion is the sum of the mass of the nucleus, the mass of the electrons and the electronic binding
energies. High accuracy mass measurements on highly charged ions in a sequence of different charge states yield informations
on atomic binding energies, i.e., the ionisation potentials. In our contribution we discuss the possibility of determining
atomic binding energies of highly charged ions to better than 20 eV via cyclotron frequency measurements in a Penning trap.
At this level of accuracy different contributions to the binding energies, like relativistic corrections, Breit corrections
and QED corrections, can be measured.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
11.
Mäckel V Klawitter R Brenner G Crespo López-Urrutia JR Ullrich J 《Physical review letters》2011,107(14):143002
We demonstrate resonant fluorescence laser spectroscopy in highly charged ions (HCI) stored in an electron beam ion trap by investigating the dipole-forbidden 1s(2)2s(2)2p (2)P(3/2)-(2)P(1/2) transition in boronlike Ar(13+) ions. Forced evaporative cooling yielded a high resolving power, resulting in an accurate wavelength determination to λ=441.255?68(26) nm. By applying stronger cooling and two-photon excitation, new optical frequency standards based upon ultrastable transitions in such HCI could be realized in the future, e.g., for the search of time variations of the fine-structure constant. 相似文献
12.
在兰州重离子加速器国家实验室电子回旋共振离子源高电荷态原子物理实验平台上,用低能(0.75keV/u≤EP/MP≤10.5keV/u,即3.8×105m/s≤vP≤1.42×106m/s)He2+,O2+和Ne2+离子束正入射到自清洁Si表面时二次电子发射产额的实验结果.结果表明电子发射产额γ近似正比于入射离子动能EP/MP.在相同动能下,γ(O)γ(Ne)γ(He),对于原子序数ZP比较大的O2+和Ne2+离子,ZP大者反而γ小,这与较高入射能量时的结果截然不同.通过计算不同入射能量下入射离子的阻止能损S,发现反冲原子对激发二次电子的作用随入射离子能量的降低显著增大,这正是导致在较低能量范围内二次电子发射产额与较高入射能量时存在差异的主要原因. 相似文献
13.
利用基于多组态Dirac-Fock(MCDF)理论方法的原子结构和性质计算程序GRASP92和全相对论扭曲波电子碰撞激发计算程序REIE06,系统计算了类氖离子(Z=50—57)激发组态2s22p53l和2s2p63l(l=s,p,d)的能级结构和碰撞激发截面,总结了碰撞激发截面随入射电子能量的变化规律,讨论了实验中感兴趣的(2p1/23d3/2)1→2s22p61S0(标记为3C线)与(2p3/23d5/2)1→2s22p61S0(标记为3D线)跃迁线强度比值的沿等电子系列特性和强组态相互作用对高离化态类氖离子截面的影响. 相似文献
14.
H.W. Schnopper J.P. Delvaille K. Kalata A.R. Sohval M. Abdulwahab K.W. Jones H.E. Wegner 《Physics letters. A》1974,47(1):61-62
Two broad spectral features which may be easily overlooked or misinterpreted in the discussion of X-ray spectra induced by fast atomic collisions are reported. Calculations based on relatively simple models are in good agreement with the data. 相似文献
15.
Masashi Monobe Hiroyuki A. Sakaue Daiji Kato Izumi Murakami Hirohisa Hara Tetsuya Watanabe Nobuyuki Nakamura 《X射线光谱测定》2020,49(4):511-514
We present extreme ultraviolet spectra of 3s3p–3s3d transitions in Fe14+ observed with a compact electron beam ion trap. The contributions of indirect excitation via a metastable state and resonant excitation are studied by observing the electron energy dependence of the spectra for the energy range of 60–210 eV. The results indicate that the 3s3d 1D2 level is directly excited from the 3s2 ground state whereas the 3s3d 3D3 level has a large contribution of the indirect excitation via the 3s3p 3P2 metastable state. Comparisons with the theoretical excitation cross sections including MNn resonant excitations show good qualitative agreement with the experimental results for the electron energy dependent features. 相似文献
16.
Safdar Ali Erina Shimizu Hiroyuki A. Sakaue Daiji Kato Izumi Murakami Norimasa Yamamoto Hirohisa Hara Tetsuya Watanabe Nobuyuki Nakamura 《Hyperfine Interactions》2015,231(1-3):45-49
Intensity ratio of density sensitive emission lines emitted from Fe ions in the extreme ultraviolet region is important for astrophysics applications. We report high-resolution intensity ratio measurements for Fe ions performed at Tokyo EBIT laboratory by employing a flat-field grazing incidence spectrometer. The experimental intensity ratios of Fe X and Fe XII are plotted as a function of electron density for different electron beam currents. The experimental results are compared with the predicted intensity ratios from the model calculations. 相似文献
17.
We show how a classical approach can be used to model electronic processes taking place when slow highly charged ions collide with surfaces. In particular we derive expressions for the distance of the first charge flow and for the image energy gain of an ion of chargeq outside a surface described by a workfunctionW and a static dielectric constant ?. 相似文献
18.
Rodolfo Sánchez Angela Braeuning-Demian Jan Glorius Siegbert Hagmann Pierre-Michel Hillenbrand Anton Kalinin Thomas Köhler Yuri A. Litvinov Nikolaos Petridis Shahab Sanjari Uwe Spillmann Thomas Stöhlker 《X射线光谱测定》2020,49(1):33-36
The atomic physics collaboration SPARC is a part of the APPA pillar at the future Facility for Antiproton and Ion Research. It aims at atomic-physics research across virtually the full range of atomic matter. An emphasis of this contribution are the atomic physics experiments addressing the collision dynamics in strong electro-magnetic fields as well as the fundamental interactions between electrons and heavy nuclei at the HESR. Here we give a short overview about the central instruments for SPARC experiments at this storage ring. 相似文献
19.
For 100 ke V Nez+ (z = 1?4) and 200 keV Arz+ (z = 1?8) colliding with noble gas atoms the fraction of electron capture processes followed by radiationless deexcitation is shown to increase with rise of z and of target atomic number. 相似文献
20.
Draganić I Crespo López-Urrutia JR DuBois R Fritzsche S Shabaev VM Orts RS Tupitsyn II Zou Y Ullrich J 《Physical review letters》2003,91(18):183001
We present the results of an experimental study of magnetic dipole (M1) transitions in highly charged argon ions (Ar X, Ar XI, Ar XIV, Ar XV) in the visible spectral range using an electron beam ion trap. Their wavelengths were determined with, for highly charged ions, unprecedented accuracy up to the sub-ppm level and compared with theoretical calculations. The QED contributions, calculated in this Letter, are found to be 4 orders of magnitude larger than the experimental error and are absolutely indispensable to bring theory and experiment to a good agreement. This method shows great potential for the study of QED effects in relativistic few-electron systems. 相似文献