Nuclear Physics

Lund University

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Facts and Figures

The experiment was conducted November 2012 at the large-scale European accelerator laboratory GSI Helmholtz Centre for Heavy-Ion Research, Darmstadt, Germany.

The experiment lasted three weeks in total - though eight weeks were recommended from the GSI International Programme Advisory Committee.

Within these three weeks, we observed 30 correlated alpha decay chains, which are as such and by and large compatible with previous reports of in total 37 such chains by the scientists at Dubna, Russia. See also What's New?

The UNILAC accelerator at GSI delivered steadily in total 6x10^18 beam particles of the stable but rare isotope 48Ca (calcium, 20 protons).

These beam particles impinged with about 6x10^12 ions per second on a rotating target wheel, which comprised four target segments containing in total roughly 5x10^19 atoms of the actinide element 243Am (95 protons). The americium material originates from Oak Ridge National Laboratory, Tennessee. The target segments were manufactured the Institute of Nuclear Chemistry at the Johannes Gutenberg-University Mainz, Germany.

The "hay stack" of non-reacting primary calcium particles and vast nuclear reaction background particles was efficiently separated from the element 115 "needles" by means of the gas-filled TASCA magnetic separator.

At the back-end, our TASISpec detection system counted at a rate of about 100 events per second.

About 1.5 decay chains associated with element 115 production were detected per day, 10 per week.

The isotope 288-115, seen in 22+31=53 decay chains in total by now, has a half-life of 160 milliseconds - or between 140 and 190 milliseconds accounting for statistical uncertainties.


The experiment worked essentially flawlessly from day 1.



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