High-power radioactive targets as one of the key problems in further development of the research program on synthesis of new superheavy elements

Abstract

Over the past decade, numerous isotopes of superheavy elements with Z = 112-118 have been synthesized. Production cross sections for these species are in the range of a few picobarns (1 pb = 10 -36 cm 2 ) or less. To get access to heavier nuclides and carry out a detailed study on their properties, a sufficient increase of the overall sensitivity of experiments is needed. The direct solution consist in increasing of the beam intensity and development of separators providing the necessary background suppression. Therefore, the design of high power radioactive targets becomes a key problem. In this report, we consider specific requirements to the development of targets for the synthesis of superheavy elements.

How elements up to 118 were reached and how to go beyond

“…such intensities over extended periods [22,23], more efficient separators, more sensitive detection systems with dead-time free data acquisition [24,25] that allow safe identification of single decay chains from new elements, and longer irradiation times. As detailed in [18], where the system 50 Ti+ 249 Cf is employed to illustrate the current situation, optimum beam energies suggested by different theoretical frameworks differ by significantly larger amounts than can be covered in a single experiment.…”

On the search for elements beyondZ=118. An outlook based on lessons from the heaviest known elements

“…Thus, it appears appropriate to reflect on which aspects should get most attention to perform the best possible experiments, thus maximizing the likelihood of success. Obvious, purely technical aspects include higher primary beam intensities, targets that can withstand such intensities over extended periods [34,35], more efficient separators, more sensitive detection systems that allow safe identification of single decay chains from new elements, and longer irradiation times. I will focus here on a different aspect: numerous theoretical calculations of maximum cross sections of the reactions presented in Table 2 have been published in recent years (see overview in [30] for the reactions leading to Z = 120), which span ranges of several orders for each reaction.…”