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Title: Measurements of the Properties of Highly-charged high-Z ions

Abstract

We had proposed carrying out a systematic experimental investigation of the atomic physics of highly charged, high-Z ions, produced in the Lawrence Livermore National Laboratory (LLNL) electron beam ion trap (EBIT-I) in its high energy mode, superEBIT. In particular we were going to accurately measure line positions for Δn=0 transitions in few electron high-Z ions; this was meant to enable us to investigate relativistic and quantum electrodynamics QED contributions to the energy levels as well as the nuclear properties of heavy ions. We were also going to measure cross sections for various electron-ion interactions, the degree of polarization of emitted x-rays, and radiation cooling rates of various ionization stages of highly charged, high-Z ions. This would enable us to study fundamental atomic physics of high-Z ions at relativistic electron impact energies and in the intense nuclear fields of highly ionized, high-Z ions. This would extend previous measurements we have carried out to a regime where there is a paucity of good data. These measurements were expected to generate increased theoretical interest and activity in this area. The project will extend a very successful collaboration between Morehouse College (MC) and a national laboratory LLNL, Minority student training and development are majormore » components of the proposal.« less

Authors:
Publication Date:
Research Org.:
Morehouse College
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
901632
Report Number(s):
DE-FG02-98ER14877
TRN: US0703567
DOE Contract Number:
FG02-98ER14877
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATOMIC PHYSICS; CROSS SECTIONS; ELECTRON BEAMS; ELECTRONS; ENERGY LEVELS; HEAVY IONS; IONIZATION; LAWRENCE LIVERMORE NATIONAL LABORATORY; NUCLEAR PROPERTIES; POLARIZATION; QUANTUM ELECTRODYNAMICS; RADIATIONS; TRAINING; Highly-charged high-Z ions, Electron Impact Excitation Cross Sections, Polarization, X-ray emmission

Citation Formats

Augustine J. Smith, Ph.D.. Measurements of the Properties of Highly-charged high-Z ions. United States: N. p., 2007. Web. doi:10.2172/901632.
Augustine J. Smith, Ph.D.. Measurements of the Properties of Highly-charged high-Z ions. United States. doi:10.2172/901632.
Augustine J. Smith, Ph.D.. Tue . "Measurements of the Properties of Highly-charged high-Z ions". United States. doi:10.2172/901632. https://www.osti.gov/servlets/purl/901632.
@article{osti_901632,
title = {Measurements of the Properties of Highly-charged high-Z ions},
author = {Augustine J. Smith, Ph.D.},
abstractNote = {We had proposed carrying out a systematic experimental investigation of the atomic physics of highly charged, high-Z ions, produced in the Lawrence Livermore National Laboratory (LLNL) electron beam ion trap (EBIT-I) in its high energy mode, superEBIT. In particular we were going to accurately measure line positions for Δn=0 transitions in few electron high-Z ions; this was meant to enable us to investigate relativistic and quantum electrodynamics QED contributions to the energy levels as well as the nuclear properties of heavy ions. We were also going to measure cross sections for various electron-ion interactions, the degree of polarization of emitted x-rays, and radiation cooling rates of various ionization stages of highly charged, high-Z ions. This would enable us to study fundamental atomic physics of high-Z ions at relativistic electron impact energies and in the intense nuclear fields of highly ionized, high-Z ions. This would extend previous measurements we have carried out to a regime where there is a paucity of good data. These measurements were expected to generate increased theoretical interest and activity in this area. The project will extend a very successful collaboration between Morehouse College (MC) and a national laboratory LLNL, Minority student training and development are major components of the proposal.},
doi = {10.2172/901632},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Apr 03 00:00:00 EDT 2007},
month = {Tue Apr 03 00:00:00 EDT 2007}
}

Technical Report:

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  • Significant new evidence is presented for resonant-transfer-and-excitation (RTE) in ion-atom collisions. This process occurs when a target electron is captured simultaneously with the excitation of the projectile followed by deexcitation via photon emission. RTE, which is analogous to dielectronic recombination (DR), proceeds via the inverse of an Auger transition, and is expected to be resonant for projectile velocities corresponding to the energy of the ejected electron in the Auger process. RTE was investigated by measuring cross sections for projectile K x-ray emission coincident with single electron capture for 15 to 200 MeV /sub 16/S/sup 13 +/, 100 to 360 MeVmore » /sub 20/Ca/sup 16 +/ /sup 17 +/ /sup 18 +/ and 180 to 460 MeV /sub 23/V/sup 19 +/ /sup 20 +/ /sup 21 +/ ions colliding with helium. Strong resonant behavior, in agreement with theoretical calculations of RTE, was observed in the coincidence cross sections.« less
  • Ionization and fragmentation have been measured for C{sub 60} molecules bombarded by highly charged (up to 35+) xenon ions with energies ranging up to 625 MeV. The observed mass distribution of positively charged fragments is explained in terms of a theoretical model indicating that the total interaction cross section contains roughly equal contributions from (a) excitation of the giant plasmon resonance, and (b) large-energy-transfer processes that lead to multiple fragmentation of the molecule. Preliminary results of measurements on VUV photons emitted in these interactions are also presented.
  • Ionization and fragmentation were measured for C{sub 60} molecules bombarded in the vapor phase by Xe{sup 35+} and Xe{sup 18+} ions with energies in the range 420-625 MeV. The CM energies exceeded those used in previous studies by several orders of magnitude. The mass distribution for the resulting positively charged fragments was determined and we studied the dependence of the fragment yields on the energy and charge of the projectiles. We developed a theoretical model that indicates the total interaction cross section contains roughly equal contributions from (1) excitation of the giant plasmon resonance, and (2) large-energy-transfer processes leading tomore » multiple fragmentation of the molecule.« less
  • High-resolution reflection-type crystal spectrometers have been used for x-ray energies up to 13 keV, e.g., the K-shell radiation of heliumlike Kr. In order to extend crystal spectrometer measurements to higher energy x rays from higher-Z elements, we employ the crystal in transmission. The geometry we use is known as DuMond geometry. Using such a transmission-type crystal x-ray spectrometer, we have measured the K-shell radiation of various highly charged high-Z ions. In particular, we present a measurement of the 1s2p{sup 1}P{sub 1}{r_arrow}1s{sup 2}{sup 1}S{sub 0} transition in heliumlike xenon, Xe{sup 52+}. For this transition, we measure a linewidth of 34 eV,more » which demonstrates that the resolving power we achieved with the new spectrometer is on the order of 1000. {copyright} {ital 1997 American Institute of Physics.}« less
  • In the process of interaction of the intense laser radiation of the iodine laser system PERUN ({lambda}=1.315 {mu}m, E{<=}50 J, {tau}{approx}350 ps, I{approx}10{sup 15} W/cm{sup 2}) with a solid tungsten and lead targets the ions with ionization states from z=1 up to z{approx}50 and energies, at least, a few of MeV are produced. Used in experiment the Thomson parabola ion spectrograph (TP) with a registration system based on the micro channel plate (MCP), gives the general view of ionization states and energies of all kinds of ions produced in one laser shot. The registered data, processed by the PC, givemore » the on-line information about the obtained experimental results. In the experiment with the TP the ring ion collector (IC), coaxial with TP axis, has been used. The quantity of the highly charged (z{approx}30-50) tungsten and lead ions was estimated from comparison of velocities of different ion groups, registered by the IC and by the TP. Maximum registered charge states for W and Pb ions were estimated as z{approx}50 at the distance L{approx}200 cm, maximum energy 6.4 MeV and 5.2 MeV, respectively. The yield of the highly charged W ions with the energies E{approx}(1.2-6.4) MeV was estimated to be N{approx}7.0x10{sup 12} sr{sup -1} and N{approx}10.5x10{sup 12} sr{sup -1} for Pb ions with the energies E{approx}(0.7-5.2) MeV.« less