Lunds universitet

Denna sida på svenska This page in English

Our Experiment - What Is New

The new component in the experiment conducted at GSI Darmstadt is the possibility to observe photons in connection with the various alpha decays of element 115 and its decendants. Photons are electromagnetic radiation - alike visible light. Here, we are interested in photons emitted from atoms (called X rays) and photons emitted from their atomic nuclei (called gamma rays) of superheavy elements.

X rays have energies characteristic for a given chemical element, a finding that dates back to the law of H.G.J Moseley from 1913. In fact, some 40 years ago the element 104, Rf, rutherfordium, was disclosed by such an X-ray fingerprinting attempt. 

We have adopted that idea and applied it for the first time to a promising case of the presumed "new" odd-proton number elements of the "Dubna Island", namely 288-115 (i.e. the nucleus with 115 protons and 173 neutrons) and its alpha-decay daughters 284-113, 280Rg, 276Mt, and 272Bh.

In our publication, which also comprises proper references to all relevant scientific articles and prior work on element 115, we describe that
(i) we observe alpha-decay chains (seemingly from element 115),
    by and large compatible with earlier data from the Dubna-Livermore collaboration,
(ii) we see two K X-ray candidates further down the alpha decay
    chain which are compatible with element 115 production. This
    number of two candidates is, of course, NOT statistically
    significant to claim firm proton number assignment, but
(iii) we obviously show the feasibility of such experiments as such
(iv) and gain unprecedented nuclear-structure data by means of
    alpha-gamma coincidences, which we measure in parallel.

In fact, the main "public" result is probably (iii), i.e. that it is possible to in principle successfully perform such X-ray fingerprinting experiments with present day technology and measuring techniques.

See also Element 115 - Proven Existence?

Information on the TASISpec setup is available. Another great - and in this field rather new - asset is the use comprehensive simulations, which in particular allow for a self-consistency check of the interpretation of the data. Two short animations can be downloaded from the TASISpec page.