Asia’s Scientific Trailblazers: Kosuke Morita

We speak to Dr. Kosuke Morita of RIKEN about his team’s jubilation on the discovery of element 113.

Dr. Kosuke Morita
RIKEN Nishina Center for Accelerator-based Science

AsianScientist (Jan. 8, 2016) – Scientists in Asia have made significant contributions to basic and applied research over the years, both big and small.

But it is always a big deal when a ‘first’ happens, such as when Kosuke Morita’s research group at Japan’s RIKEN Nishina Center for Accelerator-based Science became the first Asian team to discover and name an element on the periodic table.

Born in 1957 in Kitakyushu, Fukuoka, Japan, Morita graduated from Kyushu University in 1979 and obtained his PhD from the same university in 1993. He joined RIKEN as a research scientist in 1984, and in 2006, he became associate chief scientist of the Superheavy Element Laboratory at the RIKEN Nishina Center.

After two successful studies in 2004 and 2005, Morita’s team showed in 2012 that dubnium-262 decays into lawrencium-258 (element 103) and finally into mendelevium-254 (element 101), providing unambiguous proof of element 113 as the origin of the chain.

They would wait another three years before the Joint Working Party of the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP) officially recognized the discovery on New Year’s Eve.

IUPAC’s report will be published in an early 2016 issue of the IUPAC journal, Pure and Applied Chemistry. The RIKEN group has also been given naming rights to the new element, which sits between copernicium and flerovium on the periodic table and goes by the temporary name of ununtrium (Uut).

Asian Scientist Magazine speaks to Morita in the week following this momentous occasion. In our interview, we learn about his team’s jubilation, his research plans, and the advice he has for young scientists out there.


How does it feel to be the first Asian scientist to discover a new element?

We are really very happy to be the first group from Asia to discover and name a new element.
Do you have any candidates right now for the name of element 113?

No, I don’t. It’s like a white paper. We will start the naming procedure after we get an official letter inviting us to propose the permanent name and symbol of the new element 113. We have not received [the letter] yet.
What would you say is the most significant scientific contribution of this discovery?

We would say that one seat in the periodic table has been filled for the first time by non-European, non-American scientists.
Could you describe how you felt between 2005 and 2012 when you were trying to observe a third decay event? How did you convince yourself to continue working on this question?

Because of the preceding two events, which we believed so surely showed the existence of the specific isotope of element 113, 278[113], we convinced ourselves to continue working on it.
You mentioned previously that you will use hot fusion to discover even heavier elements on the periodic table, such as elements 119 and 120. Could you describe your next steps and experiments?

Up to now, isotope Ca-48 (Z = 20) has been used as the beam, and actinides have been used as targets, to produce superheavy elements by the hot fusion reaction.

Practically, Californium (Cf) isotopes are the target material with highest atomic number 98, and element 118 has been created with the highest atomic number (20 + 98 = 118) by hot fusion.

Now, one needs to use a beam whose atomic number greater than 20—for example Sc (Z = 21), Ti (Z = 22) or V (Z = 23)—to create superheavy elements with atomic numbers greater than 118. But no superheavy elements with an atomic number greater than 110 have been created by such beams.

We will first try to measure the cross-section (probability of the production) of a Ti-50 induced reaction with an actinide target such as 248Cm (Z = 96). After we get the value, we will proceed to create a heavier system.
Could you explain what an ‘island of stability’ means?

What I understand about the ‘island of stability’ is that it refers to an area in the nuclear chart (Z(atomic number)-N(neutron number) map) where the isotopes exhibit longer lifetimes than those in other areas around the island. While neutron number 184 is expected to be a magic number which theoretically exhibits extra stability, a magic proton number (120, 122 or 126) is not so certain, compared to the neutron’s case.
Besides element 119 and 200, how many other elements do you think will be discovered in that ‘island of stability’?

I cannot answer this question at the moment.
Why didn’t you didn’t finish your PhD thesis initially, and how did you eventually graduate?

I did not finish my doctoral thesis in my graduate course. The reason was simple: I did not have the talent to finish it. I completed my thesis at Kyushu University, nine years after I got a job at RIKEN. There, I received the degree of Doctor of Science.
Is there any advice you can give to young scientists in Asia about succeeding in science, and experimental physics in particular?

Be honest to nature.

There is no shortcut to completing any subject.

Be an optimist, and think carefully.

This article is from a monthly series called Asia’s Scientific Trailblazers. Click here to read other articles in the series.


Copyright: Asian Scientist Magazine. Photo: RIKEN.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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