TY  - FIGURE
AU  - Düllmann, Christoph Emanuel
AU  - Yakushev, Alexander
AU  - Rudolph, D.
TI  - Cover of the GSI Scientific Report 2014-1
IS  - GSI Report 2014-1
M1  - GSI-2014-02565
M1  - GSI Report 2014-1
PY  - 2014
AB  - The cover shows the set-up and the key results of the element Z=115 experiment conducted at GSI's gas-filled recoil separator TASCA. The α-photon coincidence spectroscopy set-up TASISpec consists of a box of pixelated Si-detectors with surrounding composite Ge-detectors (schematic representation top right). This setup allows detecting superheavy nuclei via their implantation and subsequent nuclear decay and their direct identification by measuring characteristic X rays. <br />For the experiment an intense <sup>48</sup>Ca beam provided by the UNILAC accelerator impinged on a radioactive <sup>243</sup>Am target wheel placed at the entrance to TASCA (photo bottom left).  30 correlated α-decay chains, assigned to element 115, were registered in TASISpec within three weeks. Twenty-two of them originated from the isotope with mass number 288 (average values given in the displayed chain at the diagonal). Observed α-photon coincidences (black histograms, upper left) include two K X-ray candidates along the decay chain, the energies of which are compatible with the assignment of the chains to element Z=115. Further coincidences led for the first time to detailed decay schemes (lower right) of superheavy elements near the predicted 'Island of Stability'. The E1 γ rays in <sup>276</sup>Mt give rise to significant constraints on nuclear structure models. A complex, but in parts still tentative, decay scheme of <sup>272</sup>Bh can explain the emission of the two K X-ray candidates. Detailed GEANT4 Monte-Carlo simulations (see TASISpec scheme, top right) were employed for the first time in an experiment on such superheavy nuclei. They allow for a crucial self-consistency check of the interpretation (decay schemes, bottom right) of the measured data (spectra, green curves, top left).<br />This experiment was selected by the American Physics Society as one of the top ten 'Physics Newsmakers of the Year 2013'. 
LB  - PUB:(DE-HGF)14
DO  - DOI:10.15120/GR-2014-1-C
UR  - https://repository.gsi.de/record/68157
ER  -