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in subjects: "Nobelium"

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Review of actinide-sediment reactions with an annotated bibliography

The annotated bibliography is divided into sections on chemistry and geochemistry, migration and accumulation, cultural distributions, natural distributions, and bibliographies and annual reviews. (LK)

Date: February 10, 1976

Creator: Ames, L. L.; Rai, D. & Serne, R. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Calculated fission properties of the heaviest elements: Vol. 2, Calculated single-particle levels in heavy nuclei

The decay properties of nuclei in many cases depend strongly on the quantum numbers of the single-particle levels in the vicinity of the Fermi surface. A striking illustration is the prolonged fission half-lives of odd nuclei relative to their even neighbors. The hindrance factor depends on the spin of unpaired odd particle and increases with increasing spin of the odd particle. The effect has been studied theoretically. For /sup 257/Fm the hindrance factor is almost ten orders of magnitude. Th… more

Date: September 1, 1986

Creator: Moeller, P.; Nix, J. R. & Swiatecki, W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Spontaneous fission properties of {sup 252,254}No and {sup 256,258}[104] and the disappearance of the outer fission barrier

The mass and total kinetic energy distributions from the spontaneous fission of {sup 252}No, {sup 254}No, {sup 256}[104], and {sup 258}[104] were measured. The results, in combination with earlier measurements for {sup 256}No, {sup 258}No, and {sup 262}No, show a sharp transition from asymmetrical mass division in {sup 256}No to symmetrical division for {sup 258}No and {sup 262}No. On the other hand, all isotopes of element 104, including {sup 260}[104], appear to yield broadly symmetrical mass… more

Date: September 1, 1993

Creator: Wild, J. F.; Hulet, E. K.; Lougheed, R. W.; Moody, K. J.; Bandong, B. B.; Dougan, R. J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Role of the second barrier upon mass division in the spontaneous fission of the heaviest elements

In the region where theorists had earlier predicted the disappearance of the outer fission barrier or of it dropping below the ground-state, we have measured the mass and total-kinetic-energy distributions from spontaneous fission of {sup 252}No, {sup 254}No, {sup 256}[104], and {sup 258}[104]. The results, in combination with earlier measurements for {sup 256}No, {sup 258}No, and {sup 262}No, show a sharp transition from asymmetrical mass division in {sup 256}No to symmetrical ones for {sup 25… more

Date: October 1, 1993

Creator: Hulet, E. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Heavy isotope production by multinucleon transfer reactions with /sup 254/Es. [101 MeV /sup 16/O, 98 MeV /sup 18/O, 127 MeV /sup 22/Ne]

Fast automated on-line and quasi-on-line radiochemical techniques were applied to search for new isotopes, to measure their decay characteristics, and to study the cross sections of the heaviest, most neutron-rich actinide isotopes in reactions of /sup 16,18/O and /sup 22/Ne projectiles with /sup 254/Es as a target. The measured yields for isotopes up to Lr-260 are three or more orders of magnitude higher than in any other reaction used so far. A comparison with data for similar transfers from … more

Date: January 1, 1985

Creator: Schaedel, M.; Bruechle, W.; Bruegger, M.; Gaeggeler, H.; Moody, K. J.; Schardt, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Calculated masses and half-lives for nuclei in the region 100 less than or equal to Z less than or equal to 110

We have calculated nuclear masses and the corresponding ..cap alpha..-decay energies O/sub ..cap alpha../ and ..cap alpha.. half-lives T/sub ..cap alpha../ by use of the folded-Yukawa macroscopic-microscopic model, for nuclei at the end of the peninsula of known elements. We have also calculated, by use of the modified oscillator model, fission half-lives for even-even nuclei with Z between 100 and 110. The results agree well with data in this region, but an interpretation of the experimental d… more

Date: January 1, 1984

Creator: Leander, G. A.; Moeller, P.; Nix, J. R. & Howard, W. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Rapid disappearance of shell effects in the fission of transfermium nuclei

In the last fifteen years we have learned that nuclear shells have a very broad and pervasive impact on the fission process. In the first few decades after the discovery of nuclear fission, the nucleus was treated as a drop of liquid with smoothly varying attractive and repulsive forces. Although this model still forms the underlying basis for fission, we also observe large effects from the superimposition of shell corrections derived from coupling the quantum states of individual nucleons. The… more

Date: January 1, 1983

Creator: Hulet, E. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Recent Searches for Superheavy Elements in Deep-Inelastic Reactions. [Approximately 7 MeV/. Mu. ]

New attempts have been made to synthesize superheavy elements (SHE) by nuclear reactions that may possibly form the products at low excitation energies. Survival of the superheavy elements would then be enhanced because of reduced losses from prompt fission. Classical and diffusion-model calculations of deep-inelastic reactions indicate there should be detectable yields of SHE formed with less than 30 MeV of excitation energy. Accordingly, superheavy elements have been sought in such reactions … more

Date: October 1, 1980

Creator: Hulet, E. K.; Lougheed, R. W. & Nitschke, J. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Calculated fission properties of the heaviest elements

A quantitative calculation is presented that shows where high-kinetic-energy symmetric fission occurs and why it is associated with a sudden and large decrease in fission half-lives. The study is based on calculations of potential-energy surfaces in the macroscopic-microscopic model and a semi-empirical model for the nuclear inertia. For the macroscopic part a Yukawa-plus-exponential model is used and for the microscopic part a folded-Yukawa single-particle potential is used. The three-quadrati… more

Date: September 1, 1986

Creator: Moeller, P.; Nix, J. R. & Swiatecki, W. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Evidence for bimodal fission in the heaviest elements

We have measured the mass and kinetic-energy partitioning in the spontaneous fission of five heavy nuclides: /sup 258/Fm, /sup 259/Md, /sup 260/Md /sup 258/No, and /sup 260/(104). Each was produced by heavy-ion reactions with either /sup 248/Cm, /sup 249/Bk, or /sup 254/Es targets. Energies of correlated fragments from the isotopes with millisecond half lives, /sup 258/No and /sup 260/(104), were measured on-line by a special rotating-wheel instrument, while the others were determined off-line … more

Date: August 1, 1987

Creator: Hulet, E. K.; Wild, J. F.; Lougheed, R. W.; Dougan, R. J.; Landrum, J. H.; Dougan, A. D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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New, heavy transuranium isotopes

In this report, we offer our most recent results concerning the decay properties for five new isotopes of Md, No, Lr, and for {sup 258m}Md. In additions to these successful experiments, we have also conducted searches for {sup 263}(105), {sup 264}(105), {sup 272}(109), and superheavy elements from bombardments of {sup 254}Es with heavy ions. {sup 2} An exciting finding in the course of this work is a new fission phenomenon, which we have termed bidmodal fission''. This is described in a subsequ… more

Date: October 22, 1990

Creator: Hulet, E. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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No⁹⁹, Ag¹¹¹ and Ba¹⁴⁰ Yields from Proton Induced Fission

The following report investigates nobelium, silver and barium yields from proton induced fission by using uranium samples to measure bombardment in the cyclotron.

Date: 1950

Creator: Jones, W. H. & Fowler, J. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Biomodal spontaneous fission

Investigations of mass and kinetic-energy distributions from spontaneous fission have been extended in recent years to an isotope of element 104 and, for half-lives, to an isotope of element 108. The results have been surprising in that spontaneous fission half-lives have turned out to be much longer than expected and mass and kinetic- energy distributions were found to abruptly shift away from those of the lighter actinides, showing two modes of fission. These new developments have caused a re… more

Date: September 26, 1989

Creator: Hulet, E.K. (Lawrence Livermore National Lab., CA (USA))

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Discovery of a new mode of nuclear fission

We measured the mass and kinetic-energy partitioning in the spontaneous fission of /sup 258/Fm, /sup 259/Md, /sup 260/Md, /sup 258/No, and /sup 260/(104). Surprisingly, these energy distributions were skewed upward or downward from the peak in each case, except for /sup 260/(104), indicating a composite of two energy distributions. We interpret this as a new mode of fission in which there is mixture of liquid-drop-like and fragment-shell-directed symmetric fission.

Date: January 1, 1986

Creator: Hulet, E. K.; Wild, J. F.; Dougan, R. J.; Lougheed, R. W.; Landrum, J. H.; Dougan, A. D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Neutron multiplicities for the transplutonium nuclides

This paper continues, with respect to the transplutonium nuclides, earlier efforts to collate and evaluate data from the scientific literature on the prompt neutron multiplicity distribution from fission and its first moment <nu> = ..sigma..nuPnu. The isotopes considered here for which P/sub nu/ and or <nu> data (or both) were found in the literature are of americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), fermium (Fm), and nobelium (No).

Date: January 1, 1985

Creator: Holden, N. E. & Zucker, M. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Prompt neutron multiplicities for the transplutonium nuclides

The direct determination of the average prompt neutron emission values is reviewed, and a method of comparing different sites of neutron emission multiplicity distribution values is described. Measured and recommended values are tabulated for these nuclides: /sup 241/Am, /sup 242/Am, /sup 242/Cm, /sup 243/Cm, /sup 244/Cm, /sup 246/Cm, /sup 247/Cm, /sup 248/Cm, /sup 250/Cm, /sup 245/Cm, /sup 249/Bk, /sup 246/Cf, /sup 249/Cf, /sup 250/Cf, /sup 252/Cf, /sup 254/Cf, /sup 251/Cf, /sup 253/Es, /sup 2… more

Date: January 1, 1985

Creator: Holden, N. E. & Zucker, M. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Leap to explore the region of neutron-rich heavy element isotopes

The research aims of the Large Einsteinium Activation Program (LEAP) are described. This program is a major initiative to exploit currently existing expertise in heavy element research and the potential for producing very heavy actinide target materials such as 285-day /sup 254/Es at the High Flux Isotope Reactor at Oak Ridge National Laboratory. The stated aims of the program are to produce heavy element isotopes, to conduct chemical studies of these isotopes, to study the nuclear properties o… more

Date: October 1, 1985

Creator: Hoffman, D.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Chemical properties of the heavier actinides and transactinides

The chemical properties of each of the elements 99 (Es) through 105 are reviewed and their properties correlated with the electronic structure expected for 5f and 6d elements. A major feature of the heavier actinides, which differentiates them from the comparable lanthanides, is the increasing stability of the divalent oxidation state with increasing atomic number. The divalent oxidation state first becomes observable in the anhydrous halides of californium and increases in stability through th… more

Date: January 1, 1981

Creator: Hulet, E. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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New fission valley for /sup 258/Fm and nuclei beyond

Experimental results on the fission properties of nuclei close to /sup 264/Fm show sudden and large changes with a change of only one or two neutrons or protons. The nucleus /sup 258/Fm, for instance, undergoes symmetric fission with a half-life of about 0.4 ms and a kinetic energy peaked at about 235 MeV whereas /sup 256/Fm undergoes asymmetric fission with a half-life of about 3 h and a kinetic energy peaked at about 200 MeV. Qualitatively, these sudden changes hve been postulated to be due t… more

Date: January 1, 1986

Creator: Moeller, P.; Nix, J. R. & Swiatecki, W. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Table of radioactive elements

As has been the custom in the past, the Commission publishes a table of relative atomic masses and halflives of selected radionuclides. The information contained in this table will enable the user to calculate the atomic weight for radioactive materials with a variety of isotopic compositions. The atomic masses have been taken from the 1984 Atomic Mass Table. Some of the halflives have already been documented.

Date: January 1, 1985

Creator: Holden, Norman E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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An Operating Transcurium Element Radiochemistry Facility

No Description Available.

Date: July 31, 1964

Creator: Coops, M. S.; Scribner, V. E. & Hanson, C. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Physics division annual report 1999

This report summarizes the research performed in the past year in the Argonne Physics Division. The Division's programs include operation of ATLAS as a national heavy-ion user facility, nuclear structure and reaction research with beams of heavy ions, accelerator research and development especially in superconducting radio frequency technology, nuclear theory and medium energy nuclear physics. The Division took significant strides forward in its science and its initiatives for the future in the… more

Date: December 6, 2000

Creator: Thayer, K., ed. & Physics

Item Type: Report

Partner: UNT Libraries Government Documents Department

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NOBELIUM: TRACER CHEMISTRY OF THE DIVALENT AND TRI-VALENTIONS

In the absence of oxidizing or reducing agents the chromatographic and coprecipitation behavior of element 102 is similar to that of the alkaline earth elements. After oxidation with ceric ions, the behavior is that expected of a trivalent actinide. The conclusion is that nobelium is the first actinide for which the +2 oxidation state is the most stable species in aqueous solution.

Date: February 1, 1968

Creator: Maly, Jaromir; Sikkeland, Torbjorn; Silva, Robert & Ghiorso, Albert.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Element No. 102

By the use of a radically new method they have succeeded in identifying unambiguously an isotope of element 102. In other careful experiments conducted over a period of many months they find that they are unable to confirm the element 102 discovery work of Fields et al. reported in 1957. The experiments at Berkeley were performed with the new heavy ion linear accelerator (HILAC) over a period of several weeks and culinated the chemical identification of an isotope of fermium (Fm{sup 250}) as th… more

Date: June 4, 1958

Creator: Ghiorso, A.; Sikkeland, T.; Walton, J. R. & Seaborg, G. T.

Item Type: Report

Partner: UNT Libraries Government Documents Department