Experiment on Synthesis of an Isotope ²⁷⁷112 by ²⁰⁸Pb+⁷⁰Zn Reaction

Abstract

The production and decay of 277 112 have been investigated using a gas-filled recoil ion separator in irradiations of 208 Pb targets with a 70 Zn beam at 349.5 MeV. We have observed two -decay chains that can be assigned to subsequent decays from 277 112 produced in the 208 Pb( 70 Zn,n) reaction. After emitting four consecutive -particles, both the chains terminate by spontaneous fission decays of 261 Rf, and the decay energies and decay times of both the chains obtained in the present work agree well with those reported by a group at Gesellschaft für Schwerionenforschung (GSI), Germany. The present result gives the first clear confirmation of the discovery of 277 112 and its -decay product 273 Ds reported previously.

Discovery of the Element with Atomic Number 112 (IUPAC Technical Report)

“…JWP ASSESSMENT: The 1996 collaboration of Hofmann et al [5] combined with the 2002 collaboration of Hofmann et al [6] are accepted as the first evidence for the synthesis of element with atomic number 112, being supported by subsequent measurements of Morita et al [16,18], and by assignment of decay properties of likely hassium intermediates [9,11,13] in the decay chain originating from 277 112. tion studies using multi-GeV protons incident on a U target clearly indicated the production path was irreproducible as previously stressed [1,3,4]. The latter refutations have been challenged by Brandt [18,25], a member of the Marinov collaboration, in which he rejects the negative results because the same exact experiment as conducted by Marinov was not followed.…”

“…The latter refutations have been challenged by Brandt [18,25], a member of the Marinov collaboration, in which he rejects the negative results because the same exact experiment as conducted by Marinov was not followed. However, independent evidence is what "Criteria" (q.v.)…”

Synthesis of superheavy elements by cold fusion

“…A detailed presentation and discussion of the GSI-SHIP results on the decay properties of elements 107 to 112 was given in previous reviews [15,38,39]. The results of experiments at RIKEN on the confirmation of elements 110 to 112 and the first production of an isotope of element 113 using a cold fusion reaction were published in [40][41][42][43][44]. A systematic work on cold fusion reactions aiming to study the influence of neutron number and of target-projectile asymmetry on the cross-section was performed at LBNL.…”

“…Decay chains measured in the cold fusion reaction 70 Zn + 208 Pb → 278 112 * . In the left part the two chains are shown, which were measured in 1996 and 2000 at SHIP [25,76], in the right part those measured in 2004 at RIKEN [43]. The chains were assigned to the isotope 277 112 produced by evaporation of one neutron from the compound nucleus.…”

New dimensions of the periodic system: superheavy, superneutronic, superstrange, antimatter nuclei

“…In the "cold" fusion reactions based on the closed shell target nuclei, lead and bismuth, SH elements up to Z = 113 have been produced [1,2]. The "world record" of 0.03 pb in production cross section of 113 element has been obtained here within more than half-year irradiation of 209 Bi target with 70 Zn beam [2]. Further advance in this direction (with Ga or Ge beams) seems to be very difficult.…”