First experiment at TASCA towards X-ray fingerprinting of element 115 decay chains

Forsberg, U.*; Golubev, P.*; Sarmiento, L. G.*; Jeppsson, J.*; Rudolph, D.*; Andersson, L.-L.*; Ackermann, D.*; Asai, Masato  ; Block, M.*; Eberhardt, K.*; Even, J.*; Dllmann, Ch. E.*; Dvorak, J.*; Gates, J. M.*; Gregorich, K. E.*; Herzberg, R.-D.*; Heberger, F. P.*; Jger, E.*; Khuyagbaatar, J.*; Kojouharov, I.*; Kratz, J. V.*; Krier, J.*; Kurz, N.*; Lahiri, S.*; Lommel, B.*; Maiti, M.*; Merchn, E.*; Omtvedt, J. P.*; Parr, E.*; Runke, J.*; Schaffner, H.*; Schdel, M.; Yakushev, A.*

The atomic numbers and mass numbers of superheavy elements produced in the reactions of Ca beam with actinide targets have not been identified with direct experimental evidences. This causes a little doubt about a new element synthesis. The aim of this study is to identify the atomic numbers of those superheavy elements through characteristic X-ray measurements. To produce and separate superheavy elements, we employed a gas-filled separator TASCA at GSI, and constructed high-efficiency --electron multi-coincidence detector setup at the focal plane of TASCA. Transmission efficiencies and focusing abilities were tested experimentally, and compared with simulations. We achieved a good performance to realize X-ray measurement for the element 115.