The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform
N. E. Holden - One of the best experts on this subject based on the ideXlab platform.
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TABLE OF THE ISOTOPES
2003Co-Authors: N. E. HoldenAbstract:This table presents an evaluated set of values for the experimental quantities that characterize the decay of radioactive Nuclides . A list of the major references used in this evaluation is given below . When uncertainties are not listed, they are assumed to be five or less in the last digit quoted . If they exceed five in the last digit, the value is prefaced by an approximate sign . For quasi-Stable Nuclides, the measured width, Γ, of the resonance is given . To estimate the approximate half-life, the Heisenberg relationship may be used, the half-life = 4 .56 × 10-22 seconds / Γ(MeV) . The effective literature cutoff date for data in this edition of the Table is December, 2005 .
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TABLE OF RADIOACTIVE ELEMENTS.
2001Co-Authors: N. E. HoldenAbstract:For those chemical elements which have no Stable Nuclides with a terrestrial isotopic composition, the data on radioactive half-lives and relative atomic masses for the Nuclides of interest and importance have been evaluated and the recommended values and uncertainties are listed.
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STANDARD ATOMIC WEIGHT VALUES FOR THE MONONUCLIDIC ELEMENTS - 2001.
2001Co-Authors: N. E. HoldenAbstract:Atomic Mass Evaluations have had a major impact on the values of the atomic weights for the twenty mononuclidic elements plus two elements, Thorium and Protactinium, which have no Stable Nuclides but a characteristic terrestrial isotopic composition. This paper reviews the history of the atomic weight values of these elements in the years, since the reference mass standard changed from {sup 16}O to {sup 12}C. There is a problem for Thorium, which is considered to have an abundance value of 100%, but is not treated as such in the Standard Atomic Weights' Table. Recommendations for handling the Standard Atomic Weight values for 2001 are presented.
Devendra Lal - One of the best experts on this subject based on the ideXlab platform.
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Cosmic ray labeling of erosion surfaces: in situ nuclide production rates and erosion models
Earth and Planetary Science Letters, 1991Co-Authors: Devendra LalAbstract:A number of in situ cosmogenic radioNuclides and Stable Nuclides have been measured in natural exposed rock surfaces with a view to study their in situ production and rock erosion rates [1]. The in situ radioNuclides can be used for a high-resolution tomography of the erosional history of an exposed surface; two Stable Nuclides (3He, 21Ne) and five radioNuclides (10Be, 26Al, 36Cl, 14C, 39Ar) having half-lives in the range of ∼ 300-1.5 × 106 yr half-life are measurable in many rock types. A prerequisite for the application of the in situ Nuclides for the study of erosional histories of surfaces is a knowledge of their production rates under different irradiation conditions; altitude, latitude, irradiation geometry and shielding. Relative nuclide production rates can be determined fairly accurately using the extensive available data on cosmic ray neutrons [2]. Absolute nuclide production rates cannot generally be predicted with any accuracy because of lack of data on excitation functions of Nuclides unless some normalization is possible, as was done in the case of several cosmic ray produced isotopes in the atmosphere [3]. Based on a recent natural calibration experiment in which erosion free surfaces exposed to cosmic radiation for ∼ 11,000 yrs were sampled, the absolute production rates of 10Be and 26Al in quartz have been accurately estimated for mountain altitudes in Sierra Nevada [4]. The absolute production rates of 10Be and 26Al in quartz can therefore be estimated fairly accurately for any given latitude and altitude. Some measurements of 14C in rocks of low erosion rate [5] similarly allow an estimate of its production rate. Attempts made to measure the in situ production rates of 3He in rocks have not yet led to a convergent production rate. In view of the importance of knowing the production rates of isotopes of He, Ne and Ar, I present here theoretical estimates of their production rates based on available cross-section data. I discuss the information that can be extracted from the study of the in situ Nuclides in rocks. Useful parameters characterizing the exposure history of a rock surface are: (1) the effective surface exposure age; and (2) the time-averaged erosion rate. The implications of these parameters for single and multiple nuclide studies are discussed in terms of the erosion models considered. © 1991.
Jens Ketelaer - One of the best experts on this subject based on the ideXlab platform.
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mass measurements on Stable Nuclides in the rare earth region with the penning trap mass spectrometer triga trap
Physical Review C, 2011Co-Authors: Jens Ketelaer, G Audi, Thomas Beyer, Klaus Blaum, M Block, Burcu R Cakirli, R F Casten, C DroeseAbstract:The masses of 15 Stable Nuclides in the rare-earth region have been measured with the Penning-trap mass spectrometer TRIGA-TRAP. This is the first series of absolute mass measurements linking these Nuclides to the atomic-mass standard {sup 12}C. Previously, nuclear reaction studies almost exclusively determined the literature values of these masses in the Atomic-Mass Evaluation. The TRIGA-TRAP results show deviations on the order of 3-4 standard deviations from the latest published values of the Atomic-Mass Evaluation 2003 for some cases. However, the binding-energy differences that are important for nuclear structure studies have been confirmed and improved. The new masses are discussed in the context of valence proton-neutron interactions using double differences of binding energies, {delta}V{sub pn}(Z,N).
C Droese - One of the best experts on this subject based on the ideXlab platform.
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mass measurements on Stable Nuclides in the rare earth region with the penning trap mass spectrometer triga trap
Physical Review C, 2011Co-Authors: Jens Ketelaer, G Audi, Thomas Beyer, Klaus Blaum, M Block, Burcu R Cakirli, R F Casten, C DroeseAbstract:The masses of 15 Stable Nuclides in the rare-earth region have been measured with the Penning-trap mass spectrometer TRIGA-TRAP. This is the first series of absolute mass measurements linking these Nuclides to the atomic-mass standard {sup 12}C. Previously, nuclear reaction studies almost exclusively determined the literature values of these masses in the Atomic-Mass Evaluation. The TRIGA-TRAP results show deviations on the order of 3-4 standard deviations from the latest published values of the Atomic-Mass Evaluation 2003 for some cases. However, the binding-energy differences that are important for nuclear structure studies have been confirmed and improved. The new masses are discussed in the context of valence proton-neutron interactions using double differences of binding energies, {delta}V{sub pn}(Z,N).
K. S. Sharma - One of the best experts on this subject based on the ideXlab platform.
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Atomic mass determinations in the region A = 183 to 201
Exotic Nuclei and Atomic Masses, 2020Co-Authors: D. K. Barillari, R. C. Barber, K. S. SharmaAbstract:The high resolution mass spectrometer at the University of Manitoba (“Manitoba II”) has routinely operated at a resolving power, M/ΔM, of 2 × 105 and has been used to determine mass differences for Stable Nuclides, with a precision usually in the range 2–5 parts in 109 of mass. Measurements are based on the property that ions of masses M and M′ follow exactly the same trajectory through any array of electric and magnetic fields, provided that the magnetic fields are constant and that all potentials are changed so that MV = M′V′ = M′(V + ΔV). Mass differences are measured in terms of the electrostatic analyser deflection voltage.
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Precise atomic mass measurements by deflection mass spectrometry
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2003Co-Authors: R. C. Barber, K. S. SharmaAbstract:Abstract Since its inception nearly 90 years ago by J.J. Thomson, the precise determination of atomic masses by the classical technique of deflecting charged particles in electric and magnetic fields has provided a large body of data on naturally occurring Nuclides. Currently, such measurements on Stable Nuclides have frequently achieved a precision of better than two parts in 109 of the mass. A review of the technique, together with a brief summary of the important historical developments in the field of precise atomic mass measurements, will be given. The more recent contributions to this field by the deflection mass spectrometer at the University of Manitoba will be provided as illustrations of the culmination of the techniques used and the applications that have been studied. A brief comparison between this and newer techniques using Penning traps will be presented.