100 years ago, the expectation to study element 117 did not exist; 100 years on, we study its production and some of its properties

On May 1, 2014, Physical Review Letters confirmed the existence of a new super-heavy element 117. Super-heavy elements are elements beyond atomic number 104. They do not exist in nature.

It is a memorable day for scientists in India. Drs Susant Lahiri and Moumita Maiti from the Saha Institute of Nuclear Physics (SINP) joined the other international collaborators led by Professor Christoph Duellmann at GSI Helmholtz Centre for Heavy Ion Research, in carrying out the historic experiment. Presently, Dr Maiti works in the Indian Institute of Technology, Roorkee.

A few atoms of the super heavy element emerged when calcium-48 ions at high energies impinged on a specially prepared target of berkelium-249 (Bk). Presently, researchers call the element ununseptium for its 117 protons (20 protons of calcium and 97 from Bk). An atom of element 117 is 40 per cent heavier than an atom of lead.

The international team consisted of 72 scientists and engineers from 16 institutions in Australia, Finland, Germany, India, Norway, Poland, Sweden, Switzerland, the United Kingdom, and the United States.

Oak Ridge National Laboratory (ORNL) in the U.S. produced 13 mg of berkelium-249 (half life of 330 days), a heavy element over an 18- month campaign by neutron irradiation at its High Flux Isotope Reactor. ORNL chemically separated and purified the isotope before shipping it to Mainz University which made the special target assembly that could withstand the intense calcium ion beams from the GSI accelerator.

Drs.Maiti and Lahiri estimated that the cost of 33mg of Bk is about $ 7.4 million. They also revealed that it was loaned to GSI.

How many of these nuclei have been produced to date? Is there a scientific need for producing more of these nuclei?

“Previous to our experiment, experimenters working at the accelerator laboratory in Russia, Dubna, have reported the observation of four atoms of the nuclei of the element 117 isotope with a mass number of 294 ....The main interest in the current generation of experiments lies in the proof that an atomic nucleus with 117 protons can exist, which means that element 117 exists,” said Prof. Christoph Duellmann, the group leader of the team and Professor at Johannes Gutenberg University Mainz. “Whether more data are needed for such a proof, will be decided by the joint working party of the International Union of Pure and Applied Chemistry and the International Union of Pure and Applied Physics, which reviews claims for the discovery of new elements and makes a judgment if the presently available data are sufficient or not.”

About any practical applications if follow up research leads to the discovery of more super-heavy elements, Prof. Duellmann said: “This cannot be foreseen at the moment. The study of super-heavy elements is currently a purely fundamental research topic. If future generations of scientists will succeed to synthesize much more stable super-heavy elements, maybe even in larger quantities, new materials would naturally be found: for example a solid block of element 117?

What will its properties be? Will it be more useful for certain applications than other known materials? “While I do not expect that the possibility of producing such quantities in the next decades, new avenues for the production of super-heavy elements may eventually be found and open these exciting prospects. If we look back only 100 years, the expectation to ever study element 117 did not yet exist.

“Hundred years later, we study its production and some of its properties. For other super-heavy elements, like flerovium (element 114), first chemical studies are conducted, with single atom quantities. The prospect that in the future it may be possible to find new materials is very fascinating.” Dr Duellmann hoped.

“The Indian team shared significantly and with responsibility, five and half months-long round the clock beam time at GSI, Darmstadt, Germany.” Dr Lahiri stated.

The Sydney Morning Herald claimed that the Australian researchers have co-created element 117; it is legitimate to call Lahiri and Maiti also the co-creators of the element.

So how did the collaboration between SINP and GSI Helmholtz Centre start? “On my personal endeavour, I started this collaboration with GSI Nuclear chemistry group, whose present spokesperson is Professor Christoph E. Duellmann” Dr Lahiri said. The Department of Atomic Energy funded SINP to carry out this and similar projects.

“It is now for more than 10 years that we are involved in the Super-Heavy Element (SHE) research (chemistry and physics of SHEs). The present result is a part of our continuous endeavour,” he added.

Former secretary of AERB

ksparth@yahoo.co.uk

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