Search for a superheavy nuclide with A=292 and neutron-deficient thorium isotopes in natural thorianite

Autor(en)

Franz Dellinger, Oliver Forstner, Robin Golser, Walter Kutschera, Alfred Priller, Peter Steier, Anton Wallner, Gerhard Winkler

Abstrakt

In the search for long-lived superheavy elements (SHEs) in nature the claim for the detection of a SHE species with A = 292 in a commercially available thorium solution at an abundance of (1–10) × 10-12 relative to 232Th using ICP-SFMS has been raised very recently by Marinov et al. The same group also claimed the finding of four long-lived isomeric states in neutron-deficient thorium isotopes at an abundance of (1–10) × 10-11 relative to 232Th using the same experimental method. The aim of our study was to examine, whether the ratios mentioned above could also be found in a natural thorium mineral, using AMS as a much more sensitive technique assuring the complete suppression of molecular background. Chemically untreated thorianite (ThO2) was used for both measurements. In addition, commercial thorium(IV) oxide (thoria) powder was also analyzed in the SHE measurements.

 

No events were observed in the A = 292 SHE search, resulting in an upper limit of 4 × 10-15 for the abundance of such a species relative to 232Th. For two neutron-deficient thorium isotopes, 211Th and 218Th, we find upper limits of 5 × 10-15. For 213Th and 217Th we observed a few events – albeit uncertain – which would put their abundance also into the 10-15 range.

Organisation(en)

Isotopenphysik

Journal

Nuclear Instruments & Methods in Physics Research. Section B. Beam Interactions with Materials and Atoms

Band

268

Seiten

1287-1290

Anzahl der Seiten

4

ISSN

0168-583X

DOI

https://doi.org/10.1016/j.nimb.2009.10.154

Publikationsdatum

2010

Peer-reviewed

Ja

ÖFOS 2012

1030 Physik, Astronomie, 103014 Kernphysik

Link zum Portal

https://ucris.univie.ac.at/portal/de/publications/search-for-a-superheavy-nuclide-with-a292-and-neutrondeficient-thorium-isotopes-in-natural-thorianite(ee2d1bc3-59fb-4f86-8c81-b81b7e8e6e9f).html