Actinide targets for the synthesis of super-heavy elements

Roberto, J. B.; Alexander, C.W.; Boll, R. A.; Burns, Jonathan D.; Ezold, Julie G.; Felker, L. K.; Hogle, Susan; Rykaczewski, K. P.

doi:10.1016/j.nuclphysa.2015.06.009

Cited by 91 publications

(46 citation statements)

References 60 publications

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“…In such reactions involving heavy elements the dominant reaction processes are quasifission (QF) and fusion-fission (FF), which are expected to strongly suppress the formation of an evaporation residue at higher excitation energies. For this reason it was a major surprise to observe that the so called hot fusion reactions, despite of their higher excitation energy, were able to synthesize elements Z=113-118 [9,10]. The hot fusion reactions utilized actinide targets with 48 Ca projectiles.…”

Section: Introductionmentioning

confidence: 99%

Quasifission Dynamics in Microscopic Theories

Godbey

Umar

2020

Front. Phys.

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In the search for superheavy elements quasifission reactions represent one of the reaction pathways that curtail the formation of an evaporation residue. In addition to its importance in these searches quasifission is also an interesting dynamic process that could assist our understanding of many-body dynamical shell effects and energy dissipation thus forming a gateway between deep-inelastic reactions and fission. This manuscript gives a summary of recent progress in microscopic calculations of quasifission employing time-dependent Hartree-Fock (TDHF) theory and its extensions.

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Section: Introductionmentioning

confidence: 99%

Quasifission Dynamics in Microscopic Theories

Godbey

Umar

2020

Front. Phys.

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“…[20,21] However,e ven with the case for developing the fundamental chemistry of these elements being hindered, both berkelium and californium have importantu ses as targets for fusion reactions that yield SHEs such as tennessine (Z = 117) and oganesson (Z = 118), and perhaps even in preparing elements that are not currently known. [22,23] In addition, while chemists often view the radioactive decay of actinides as an uisancea nd hazard, the spontaneous fission of 252 Cf (t1 = 2 = 2.6 y), and the resultant high flux of neutrons,h as led to numerous applications in portable neutron activation analysis, for whichi ti si nh igh demandi nt he petroleum and miningi ndustries. [24,25] Finally, during the Eisenhower administration substantial efforts were made to alter the course of the atomic era from one that developedh orrifying weapons of mass destruction to methods for unifying humanity,t hat is, the "Atomsf or Peace" program.…”

Section: Introductionmentioning

confidence: 99%

Contemporary Chemistry of Berkelium and Californium

White

Dan

Albrecht‐Schönzart

2019

Chemistry A European J

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The merging of small‐scale syntheses and rapid crystallization methods have provided access to crystalline samples of berkelium (Z=97) and californium (Z=98) coordination complexes and compounds that can be interrogated with a suite of spectroscopic tools and structural elucidation approaches that have come online over the last 20 years. The combination of this experimental data with relativistic theoretical methods that capture the effects of spin‐orbit coupling and scalar relativistic effects have allowed us to understand the electronic structure of berkelium and californium compounds at a level of detail that was not previously possible. The harbinger of this new era of post‐curium chemistry was the synthesis and characterization of [Cf{B6O8(OH)5}]. This compound possesses a structure type that is distinct from earlier actinide borates, a reduction in coordination number for californium, contracted Cf−O bond lengths, a substantially reduced magnetic moment with respect to the calculated free‐ion moment and, most importantly, vibronically coupled broadband photoluminescence. Ligand‐field analysis also showed that the splitting of the ground state was larger than typically found in the f‐block elements, and when taken together places its overall electronic structure as a hybrid of d‐ and f‐block components. The discovery of the unusual properties of this compound has led to the development of large families of 4f and 5f coordination complexes, in an effort to uncover the underlying origin of the electronic structure oddities, and whether there really is a sharp onset of these changes at californium. This in turn pushed the development of far more challenging berkelium chemistry (from a radiologic standpoint) because the half‐life of the isotopes decreases from 351 years for 249Cf to 330 days for 249Bk. This short review details some of the chemistry that has been reported over the last 15 years, and its consequences for understanding the periodic table.

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“…The one caveat is that the corresponding target materials would have to be 99 Es and 100 Fm, which are not available in quantities that suffice to make targets for such synthesis experiments. Current technology for the production of transuranium isotopes, e.g., at the ORNL's High Flux Isotope Reactor (HFIR) is capable of producing µg and pg amounts of long-lived 99 Es and 100 Fm isotopes, respectively [17], which is orders of magnitude less than the experiments discovering and studying the heaviest known elements required. Still, fusion reactions with actinide targets are generally expected to provide the highest cross sections for the synthesis of new elements with Z≥119.…”

Section: The Search For New Elements Beyond Ogmentioning

confidence: 99%

How elements up to 118 were reached and how to go beyond

Düllmann

2017

EPJ Web Conf.

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Abstract. The new superheavy elements with Z=113, 115, 117, and 118 were recently accepted into the periodic table and have been named. Elements with Z≥112 are predominantly produced in 48 Ca-induced fusion reactions on actinide targets. This pathway is exhausted at Z=118 due to the lack of target materials with sufficiently high proton number to reach elements with Z≥119. Search experiments for yet heavier elements were performed at GSI Darmstadt and FLNR Dubna. Cf, leading to Z=120, have been studied. Despite a total duration of these experiments of more than one year, neither succeeded in the identification of a new element.

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Actinide targets for the synthesis of super-heavy elements

Cited by 91 publications

References 60 publications

Quasifission Dynamics in Microscopic Theories

Quasifission Dynamics in Microscopic Theories

Contemporary Chemistry of Berkelium and Californium

How elements up to 118 were reached and how to go beyond

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