A search for superheavy elements with half-lives between a few minutes and several hundred days, produced in the 48Ca+248Cm reaction

doi:10.1016/0022-1902(78)80372-8

Journal of Inorganic and Nuclear Chemistry

Volume 40, Issue 4, 1978, Pages 589-595

https://doi.org/10.1016/0022-1902(78)80372-8 Get rights and content

Abstract

The results of recent unsuccessful attempts to synthesize and identify superheavy elements at the Lawrence Berkeley Laboratory SuperHILAC are described. A thin ²⁴⁸Cm target was irradiated with ⁴⁸Ca ions at an average energy in the target of 255 MeV. Direct counting of thin recoil foils for short-lived spontaneous fission activity was done. Two long irradiations were also made and radiochemical group separations for the superheavy elements were carried out.

In the first radiochemical experiment, a thin superheavy element sample was prepared and has been continuously counted for spontaneous fission events in a dual surface barrier coincidence counter. In the second experiment, two superheavy element fractions were obtained and were counted for spontaneous fission events; the two fractions contained those elements that co-precipitated with copper sulfide from either an acid or basic solution.

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Cited by (24)

Superheavy nuclei from 48Ca-induced reactions
2015, Nuclear Physics A
The discovery and investigation of the new region of superheavy nuclei at the DGFRS separator based on fusion reactions of ⁴⁸Ca with ²³⁸U–²⁴⁹Cf target nuclei are reviewed. The production cross sections and summaries of the decay properties, including the results of the posterior experiments performed at the SHIP, BGS, and TASCA separators, as well as at the chemistry setups, are discussed and compared with the theoretical calculations and the systematic trends in the α-decay and spontaneous fission properties. The properties of the new nuclei, isotopes of elements 112–118, and their decay products demonstrate significant increases in the stability of the heaviest nuclei with increasing neutron number and closer approach to magic number $N = 184$ .
Attempts to produce superheavy elements by fusion of 48Ca with 248Cm in the bombarding energy range of 4.5-5.2 MeV/u
1986, Journal of The Less-Common Metals
A search for superheavy elements which are expected to occur around the predicted nuclear shell closures at atomic number 114 and neutron number 184 was made in bombardments of ²⁴⁸Cm with ⁴⁸Ca ions. We have carried out this search at energies close to the Coulomb barrier to keep the excitation energy of the compound nucleus Z = 116, A = 296 as low as possible. The experiments were performed at the accelerators SUPERHILAC (Lawrence Berkeley Laboratory (LBL)) and UNILAC (GSI) and used a variety of improved physical and chemical techniques for the isolation and detection of superheavy elements to increase the sensitivity relative to earlier experiments. The small-angle separator system (SASSY) at LBL and the separator for heavy-ion reaction products (SHIP) at GSI were used for shortlived nuclides, and several radiochemical techniques were applied for longer half-lives. Although a broad range of half-lives, 10⁻⁶ to 10⁸ s, and excitation energies, 16 to 40 MeV, has been examined, no evidence for the formation of superheavy elements with cross sections greater than 10⁻³⁴ to 10⁻³⁵ cm² was found.
Heaviest nuclei from 48Ca-induced reactions
2007, Journal of Physics G: Nuclear and Particle Physics
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2014, The Chemistry of Superheavy Elements
The reaction 48Ca + 248Cm → 296116* studied at the GSI-SHIP
2012, European Physical Journal A
The Synthesis and Properties of Superheavy Nuclei Produced in the 48Ca+244Pu,248Cm Reactions
2001, Acta Physica Hungarica New Series Heavy Ion Physics

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^☆: Work supported by Division of Physical Research, U.S. Department of Energy.

^‡: Present address: LBL, University of California, Berkeley, CA 94720, U.S.A.

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Journal of Inorganic and Nuclear Chemistry

Abstract

References (25)

Nucl. Phys.

Nucl. Phys.

Inorg. Nucl. Chem. Lett.

Nucl. Inst. Meth.

Nucl. Data

LBL-666

Phys. Rev.

UCRL-11980

LBL-2366

Ann. Rev. Nuc. Sci.

Cited by (24)

Superheavy nuclei from <sup>48</sup>Ca-induced reactions

Attempts to produce superheavy elements by fusion of <sup>48</sup>Ca with <sup>248</sup>Cm in the bombarding energy range of 4.5-5.2 MeV/u

Heaviest nuclei from <sup>48</sup>Ca-induced reactions

Synthesis of superheavy elements

The reaction <sup>48</sup>Ca + <sup>248</sup>Cm → <sup>296</sup>116<sup>*</sup> studied at the GSI-SHIP

The Synthesis and Properties of Superheavy Nuclei Produced in the <sup>48</sup>Ca+<sup>244</sup>Pu,<sup>248</sup>Cm Reactions

A search for superheavy elements with half-lives between a few minutes and several hundred days, produced in the 48Ca+248Cm reaction☆

Abstract

Nucl. Phys.

Nucl. Phys.

Inorg. Nucl. Chem. Lett.

Nucl. Inst. Meth.

Nucl. Data

LBL-666

Phys. Rev.

UCRL-11980

LBL-2366

Ann. Rev. Nuc. Sci.

A search for superheavy elements with half-lives between a few minutes and several hundred days, produced in the ⁴⁸Ca+²⁴⁸Cm reaction☆