Toward the Discovery of New Elements: Production of Livermorium ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mi>Z</mml:mi> <mml:mo>=</mml:mo> <mml:mn>116</mml:mn> </mml:mrow> </mml:math> ) with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mmultiscripts> <mml:mrow> <mml:mi>Ti</mml:mi> </mml:mrow> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>50</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:mrow> </mml:math>
J. M. Gates, R. Orford, D. Rudolph, C. Appleton, B. M. Barrios, J. Y. Benitez, Martin Wladislas Bordeau, W. Botha, C. M. Campbell, John Chadderton, Alexander T. Chemey, R. M. Clark, H. L. Crawford, John D. Despotopulos, O. Dorvaux, N. E. Esker, P. Fallon, C. M. Folden, Б. Галл, F. H. Garcia, P. Golubev, J. A. Gooding, M. Grebo, Κ. Ε. Gregorich, Miguel G. Guerrero, Rachel Henderson, R.-D. Herzberg, Y. Hrabar, T. King, M. Kireeff Covo, Alexander Kirkland, R. Krücken, E. Leistenschneider, E. M. Lykiardopoulou, M. McCarthy, J. A. Mildon, C. Müller-Gatermann, L. Phair, J. L. Pore, E. Rice, Krzysztof Rykaczewski, B. N. Sammis, L. G. Sarmiento, D. Seweryniak, D. K. Sharp, Aland Sinjari, P. Steinegger, M. A. Stoyer, Julia E. Szornel, Keenan Thomas, D. S. Todd, Panov Vo, Vanessa Watson, P. T. Wooddy
Abstract
The ^{244}Pu(^{50}Ti,xn)^{294-x}Lv reaction was investigated at Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. The experiment was aimed at the production of a superheavy element with Z≥114 by irradiating an actinide target with a beam heavier than ^{48}Ca. Produced Lv ions were separated from the unwanted beam and nuclear reaction products using the Berkeley Gas-filled Separator and implanted into a newly commissioned focal-plane detector system. Two decay chains were observed and assigned to the decay of ^{290}Lv. The production cross section was measured to be σ_{prod}=0.44(_{-0.28}^{+0.58}) pb at a center-of-target center-of-mass energy of 220(3) MeV. This represents the first published measurement of the production of a superheavy element near the "island of stability," with a beam of ^{50}Ti and is an essential precursor in the pursuit of searching for new elements beyond Z=118.