Search for Superheavy Elements in Terrestrial Matter

Grimm, W.; Herrmann, G.; Schüßler, H.‐D.

doi:10.1103/physrevlett.26.1040

Cited by 33 publications

(4 citation statements)

References 17 publications

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“…Predicted half-lives based on the Strutinsky model using various parameter sets differed by many orders of magnitude [15,[19][20][21][22][23][24][25][26][27]. Some of the half-lives approached the age of the universe, and attempts have been made to discover naturally occurring SHN [28][29][30]. Although the corresponding discoveries were announced from time to time, none of them could be substantiated after more detailed inspection.…”

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confidence: 99%

Review of even element super-heavy nuclei and search for element 120

et al. 2016

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The reaction 54 Cr + 248 Cm was investigated at the velocity filter SHIP at GSI, Darmstadt, with the intention to study production and decay properties of isotopes of element 120. Three correlated signals were measured, which occurred within a period of 279 ms. The heights of the signals correspond with the expectations for a decay sequence starting with an isotope of element 120. However, a complete decay chain cannot be established, since a signal from the implantation of the evaporation residue cannot be identified unambiguously. Measured properties of the event chain are discussed in detail. The result is compared with theoretical predictions. Previously measured decay properties of even element super-heavy nuclei were compiled in order to find arguments for an assignment from the systematics of experimental data. In the course of this review, a few tentatively assigned data could be corrected. New interpretations are given for results which could not be assigned definitely in previous studies. The discussion revealed that the cross-section for production of element 120 could be high enough so that a successful experiment seems possible with presently available techniques. However, a continuation of the experiment at SHIP for a necessary confirmation of the results obtained in a relatively short irradiation of five weeks is not possible at GSI presently. Therefore, we decided to publish the results of the measurement and of the review as they exist now. In the summary and outlook section we also present concepts for the continuation of research in the field of super-heavy nuclei. 1 Introduction, theoretical background, and status of experiments Scientific attempts to synthesize new elements beyond uranium started in the middle of the 1930s, when the

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Review of even element super-heavy nuclei and search for element 120

et al. 2016

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“…Predicted half-lives based on the Strutinsky model using various parameter sets differed by many orders of magnitude. Some of the half-lives approached the age of the universe, and attempts have been made to discover naturally occurring SHN [36][37][38][39]. Although the corresponding discoveries were announced from time to time, none of them could be substantiated after more detailed inspection.…”

Section: Review and Status Of Experimentsmentioning

confidence: 99%

Eighty years of research on super-heavy nuclei

Hofmann

2018

EPJ Web Conf.

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Professor Walter Greiner, our mentor, colleague, and friend, passed away in the age of eighty. During his lifetime, the search for elements beyond uranium started and elements up to the so far heaviest one with atomic number 118 were discovered. In this talk I will present a short history from early searches for ‘trans-uraniums’ up to the production and safe identification of shell-stabilized ‘Super-Heavy Nuclei’ (SHN). The nuclear shell model reveals that these nuclei should be located in a region with closed shells for the protons at Z = 114, 120 or 126 and for the neutrons at N = 184. The outstanding aim of experimental investigations is the exploration of this region of spherical SHN. Systematic studies of heavy ion reactions for the synthesis of SHN revealed production cross-sections which reached values down to one picobarn and even below for the heaviest species. The systematics of measured cross-sections can be understood only on the basis of relatively high fission barriers as predicted for nuclei in and around the island of SHN. A key role in answering some of the open questions plays the synthesis of isotopes of element 120. Attempts aiming for synthesizing this element at the velocity filter SHIP will be reported.

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“…Predicted half-lives based on calculations using various parameter sets differed by many orders of magnitude [15,17,[20][21][22][23][24]. Some of the half-lives approached the age of the universe, and attempts have been made to discover naturally occurring SHN [25,26]. Although the corresponding discoveries were announced from time to time, none of them could be substantiated after more detailed inspection.…”

Section: The Discovery Of the Island Of 'Super-heavy Nuclei' (Shn)mentioning

confidence: 99%

Super-heavy nuclei

Hofmann¹

2015

J. Phys. G: Nucl. Part. Phys.

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Scientifically based searches for elements beyond uranium started after the discovery of the neutron. Neutrons captured by uranium nuclei and subsequent bdecay, similarly as most of the elements were produced in nature, was the successful method applied. However, as a first result, Hahn and Strassmann discovered nuclear fission indicating a limit for the existence of nuclei at an increasing number of protons. Eventually, the nuclear shell model allowed for a more accurate calculation of binding energies, half-lives and decay modes of the heaviest nuclei. Theoreticians predicted a region of increased stability at proton number Z = 126, later shifted to 114, and neutron number N = 184. These nuclei receive their stability from closed shells for the protons and neutrons. Later, increased stability was also predicted for deformed nuclei at Z = 108 and N = 162. In this review I will report on experimental work performed on research to produce and identify these super-heavy nuclei (SHN). Intensive heavy ion beams, sophisticated target technology, efficient electromagnetic ion separators, and sensitive detector arrays were the prerequisites for discovery of 12 new elements during the last 40 years. The results are described and compared with theoretical predictions and interpretations. An outlook is given on further improvement of experimental facilities which will be needed for exploration of the extension and structure of the island of SHN, in particular for searching for isotopes with longer halflives predicted to be located in the south east of the island, for new elements, and last not least, for surprises which, naturally, emerge unexpectedly.

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Search for Superheavy Elements in Terrestrial Matter

Cited by 33 publications

References 17 publications

Review of even element super-heavy nuclei and search for element 120

Review of even element super-heavy nuclei and search for element 120

Eighty years of research on super-heavy nuclei

Super-heavy nuclei

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