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in subjects: "Electron Capture"

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Atomic and Nuclear Physics Studies With Accelerators

No Description Available.

Date: December 31, 1972

Creator: Leachman, R. B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Charge exchange processes involving iron ions

A review and evaluation is given of the experimental data which are available for charge exchange processes involving iron ions and neutral H, H/sub 2/ and He. Appropriate scaling laws are presented, and their accuracy estimated for these systems. A bibliography is given of available data sources, as well as of useful data compilations and review articles. A procedure is recommended for providing single approximate formulae to the fusion community to describe total cross sections for electron c… more

Date: January 1, 1985

Creator: Phaneuf, R.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Cosmic ray half life of sup 54 Mn

A search for the {beta}{sup +} decay of {sup 54}Mn has established an upper limit of 4.4 {times} 10{sup {minus}8} for this branching ratio, and a lower limit of 13.3 for the log ft value for this second forbidden unique transition. Assuming that the {beta}{sup {minus}} decay branch has the same log ft value, then its partial half life must be greater than 4 {times} 10{sup 4} years. Experiments to directly measure the {beta}{sup {minus}} decay rate of {sup 54}Mn are now in progress. 6 refs., 2 f… more

Date: August 1, 1989

Creator: Norman, E.B.; Sur, B.; Vogel, K.R.; Lesko, K.T.; Larimer, R.M. & Browne, E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Production of low energy positive ions suitable for double electron capture systems

Single aperture beam extraction studies have been made of a new technique to produce low divergence beams of about 0.4/sup 0/ HWHM at about 15 keV to 40 keV. Computer calculations show that this technique of coating the plasma side of the plasma grid with about 0.01'' of Al/sub 2/O/sub 3/ can also be extended to the 0.5 keV to 5 keV range with beam optics less than 1/sup 0/. Source performance including results from multiaperture source operation will be discussed.

Date: January 1, 1977

Creator: Whealton, J H; Tsai, C C; Grisham, L R & Stirling, W L

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Dynamic screening and wake effects on electronic excitation in ion-solid and ion-surface collisions

The collective electronic response in a solid effectively alters ionic and atomic potentials giving rise to dynamic screening and to a wake'' of density fluctuations trailing ions as they propagate through the solid. The presence of dynamic screening modifies electronic excitation processes of projectiles in ion-solid collisions as compared to binary ion-atom collisions. We review recent theoretical and experimental studies directed at the search for and identification of signatures of dynamic … more

Date: January 1, 1991

Creator: Burgdoerfer, J. (Tennessee Univ., Knoxville, TN (United States). Dept. of Physics Oak Ridge National Lab., TN (United States))

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electronegative gases

Recent knowledge on electronegative gases essential for the effective control of the number densities of free electrons in electrically stressed gases is highlighted. This knowledge aided the discovery of new gas dielectrics and the tailoring of gas dielectric mixtures. The role of electron attachment in the choice of unitary gas dielectrics or electronegative components in dielectric gas mixtures, and the role of electron scattering at low energies in the choice of buffer gases for such mixtur… more

Date: January 1, 1981

Creator: Christophorou, L.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Cosmic ray half life of sup 56 Ni

A search for the {beta}{plus} decay of {sup 56}Ni has established an upper limit on the branching ratio of 7.2 {times} 10{sup {minus} 7} for the most likely such transition. This provides a lower limit of 2.3 {times} 10{sup 4} years for the cosmic ray half life of {sup 56}Ni. 2 refs., 2 figs.

Date: August 1, 1989

Creator: Norman, E.B.; Sur, B.; Lesko, K.T.; Larimer, R.M. & Browne, E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Criteria for the selection of nuclides for radioimmunotherapy

This report describes many factors that need to be considered if radioimmunotherapy is to become a commonplace reality. For beta-emitting radionuclides, two physical features of importance are half-life and energy, with the latter determining the range. These features must be matched to the pharmacokinetics of the carrier and the distribution of the radionuclide, both macroscopically and microscopically. Alpha-particle emitters could be considered for cells that are readily accessible to the la… more

Date: January 1, 1986

Creator: Adelstein, S. J. & Kassis, A. I.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Atomic physics at the Argonne PII ECR (electron cyclotron resonance) Ion Source

An atomic physics beam line has been set up at the Argonne PII ECR Ion Source. The source is on a 350-kV high-voltage platform which is a unique feature of particular interest in work on atomic collisions. We describe our planned experimental program which includes: measurement of state-selective electron-capture cross sections, studies of doubly-excited states, precision spectroscopy of few-electron ions, tests of quantum electrodynamics, and studies of polarization transfer using optically pu… more

Date: January 1, 1987

Creator: Dunford, R. W.; Berry, H. G.; Billquist, P. J.; Pardo, R. C.; Zabransky, B. J.; Bakke, E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Application of ECR ion source beams in atomic physics

The availability of intense, high charge state ion beams from ECR ion sources has had significant impact not only on the upgrading of cyclotron and synchrotron facilities, but also on multicharged ion collision research, as evidenced by the increasing number of ECR source facilities used at least on a part time basis for atomic physics research. In this paper one such facility, located at the ORNL ECR source, and dedicated full time to the study of multicharged ion collisions, is described. Exa… more

Date: January 1, 1987

Creator: Meyer, F.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Ultrarelativistic atomic collisions

Calculations of the coherent production of free pairs and of pair production with electron capture from ultrarelativistic ion-ion collisions are discussed. Theory and experiment are contrasted, with some conjectures on the possibility of new phenomena. 29 refs., 5 figs., 1 tab.

Date: January 1, 1991

Creator: Bottcher, C. & Strayer, M. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Delayed-fission properties of neutron-deficient americium nuclei

Characteristics of the delayed-fission decay mode in light americium nuclei have been investigated. Measurements on the unknown isotopes {sup 230}Am and {sup 236}Am were attempted, and upper limits on the delayed-fission branches of these nuclei were determined. Evidence of the existence of {sup 236}Am was observed in radiochemical separations. Total kinetic energy and mass-yield distributions of the electron-capture delayed-fission mode were measured for {sup 232}Am (t{sub 1/2} = 1.31 {plus mi… more

Date: October 23, 1989

Creator: Hall, H.L. (California Univ., Berkeley, CA (USA). Dept. of Chemistry)

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Electron capture in very low energy collisions of multicharged ions with H and D in merged beams

An ion-atom merged-beams technique is being used to measure total absolute electron-capture cross sections for multicharged ions in collisions with H (or D) in the energy range between 0.1 and 1000 eV/amu. Comparison between experiment and theory over such a large energy range constitutes a critical test for both experiment and theory. Total capture cross-section measurements for O{sup 3+} H(D) and O{sup 5+} + H(D) are presented and compared to state selective and differential cross section cal… more

Date: January 1, 1991

Creator: Havener, C.C.; Meyer, F.W. & Phaneuf, R.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A neutral-beam diagnostic for fast confined alpha particles in a burning plasma: Application on CIT (Compact Ignition Tokamak)

Diagnostic methods for fast confined alpha particles are essential for a burning-plasma experiment. We review one- and two-electron-capture methods using energetic neutral beams, and provide quantitative estimates of signal level for a two-electron-capture method applicable to CIT. The best probe is a ground-state helium-atom beam because of its relatively good penetration into a CIT plasma and the large cross section for two-electron capture; it can be produced in useful quantities from HeH/su… more

Date: October 1, 1987

Creator: Schlachter, A. S.; Stearns, J. W. & Cooper, W. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Multiple electron capture in close ion-atom collisions

Collisions in which a fast highly charged ion passes within the orbit of K electron of a target gas atom are selected by emission of a K x-ray from the projectile or target. Measurement of the projectile charge state after the collision, in coincidence with the K x-ray, allows measurement of the charge-transfer probability during these close collisions. When the projectile velocity is approximately the same as that of target electrons, a large number of electrons can be transferred to the proje… more

Date: July 24, 1989

Creator: Schlachter, A. S.; Stearns, J. W.; Berkner, K. H.; Bernstein, E. M.; Clark, M. W.; DuBois, R. D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Multiple electron capture in close ion-atom collisions

Multiple electron capture is reported for Ca/sup 17 +/ in Ar. Close collisions are defined by the observation of a coincident Ca K or Ar K x-ray. A large number of electrons is transferred to the projectile in a single close collision when the Ca ion projectile is of the order of the Ar L-shell electron velocity. The cross section for electron capture is reported.

Date: October 1, 1987

Creator: Schlachter, A.S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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2007 Nuclear Data Review

The results of a review and evaluation of neutron and non-neutron nuclear data published in the scientific literature are presented. The status of new chemical elements is examined. Data on revised values for the isotopic composition of the elements are reviewed and recommended values are presented. Half-lives of very long-lived nuclides are presented, including double beta decay, double electron capture, long-lived alpha decay and long-lived beta decay. Data from new measurements on the very h… more

Date: May 5, 2008

Creator: Holden, N. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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ELECTROCHEMISTRY OF EXCITED MOLECULES: PHOTO-ELECTROCHEMICALREACTIONS OF CHLOROPHYLLS. I

Semiconductors with a sufficiently large energy gap, in contact with an electrolyte, can be used as electrodes for the study of electrochemical reactions of excited molecules. The behavior of excited chlorophyll molecules at single crystal ZnO-electrodes has been investigated. These molecules inject electrons from excited levels into the conduction band of the electrode, thus giving rise to an anodic photocurrent. The influence of various agents on this electron transfer has been studied. In th… more

Date: December 1, 1970

Creator: Tributsch, Helmut & Calvin, Melvin.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Low Mass Francium and Emanation Isotopes of High AlphaStability

Isotopes of francium with 126 or fewer neutrons have been looked for in bombardments of Th{sup 232} with 350 Mev protons from the 184-inch cyclotron. Fr{sup 212} with an apparent half-life of 19.3 minutes for branching decay by alpha emission (44%) to At{sup 208} and by orbital electron capture (56%) to Em{sup 212} has been found. Em{sup 212} is shown to be a 23-minute alpha-emitter. At{sup 208} decays primarily (99.5%) by orbital electron capture to Po{sup 208}, but shows 0.5% alpha-branching.… more

Date: October 10, 1949

Creator: Hyde, E. K.; Ghiorso, A. & Seaborg, G. T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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New Low Mass Isotopes of Emanation (Element 86)

Among the spallation products obtained from the 350-Mev proton bombardment of Th{sup 232} they have identified two gaseous alpha-emitters which apparently do not decay into any presently known alpha-decay chains. The half-lives observed for the decay of the alpha-activities are 23 minutes and 2.1 hours. These half-lives may be principally determined by an unknown amount of orbital electron capture. At least one alpha-emitting daughter (about 4 hours half-life) has been observed to grow from a g… more

Date: September 5, 1949

Creator: Ghiorso, A.; Meinke, W. W. & Seaborg, G. T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The New Element Californium (Atomic Number 98)

Definite identification has been made of an isotope of the element with atomic number 98 through the irradiation of Cm{sup 242} with about 35-Mev helium ions in the Berkeley Crocker Laboratory 60-inch cyclotron. The isotope which has been identified has an observed half-life of about 45 minutes and is thought to have the mass number 244. The observed mode of decay of 98{sup 244} is through the emission of alpha-particles, with energy of about 7.1 Mev, which agrees with predictions. Other consid… more

Date: June 19, 1950

Creator: Thompson, S. G.; Street Jr., K.; Ghiorso, A. & Seaborg, G. T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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CHEMICAL PROPERTIES OF BERKELIUM

The recent production by Thompson, Ghiorso, and Seaborg of a radioactive isotope of berkelium (atomic number 97) makes it possible to investigate the chemical properties of this transuranium element by means of the tracer technique. This isotope has been prepared through the bombardment of Am{sup 241} with about 35 Mev helium ions in the 60-inch cyclotron of the Crocker Laboratory and is believed to have the mass number 243, or possibly 244. This Bk{sup 243} has a half-life of 4.6 hours and dec… more

Date: February 24, 1950

Creator: Thompson, Stanley G. & Seaborg, Glenn T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Search for Oscillation of the Electron-Capture Decay Probability of Pm-142

We have searched for time modulation of the electron capture decay probability of 142Pm in an attempt to confirm a recent claim from a group at the Gesellschaft fur Schwerionenforschung (GSI). We produced 142Pm via the 124Sn(23Na, 5n)142Pm reaction at the Berkeley 88-Inch Cyclotron with a bombardment time short compared to the reported modulation period. Isotope selection by the Berkeley Gas-filled Separator is followed by implantation and a long period of monitoring the 142Nd K alpha x-rays fr… more

Date: July 3, 2008

Creator: Vetter, Paul A; Vetter, Paul; Clark, Roderick; Dvorak, Jan; Freedman, Stuart; Gregorich, Kenneth et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Alpha-Decay in Isotopes of Atomic Number Less Than 83

Some time ago we started work in an attempt to observe alpha-particle decay in isotopes of atomic number less than 83. In the first experiments, thin targets of gold leaf were bombarded with 190-Mev deuterons in the 184-inch cyclotron. Two alpha-decay periods were observed in these targets; one of 0.7 minutes half-life and another of 4.3 minutes half-life. The alpha-particle energies were 5.7 and 5.2 Mev, respectively. Chemical separations proved that the 4.3-minute period is due to a gold isot… more

Date: September 5, 1949

Creator: Thompson, S. G.; Ghiorso, A.; Radmussen, J. O. & Seaborg, G. T.

Item Type: Report

Partner: UNT Libraries Government Documents Department