Spectroscopy and GEANT4 Simulations of Element 115 Decay Chains

Abstract

A high-resolution α, electron, X-ray and γ-ray coincidence experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung GmbH in Darmstadt, Germany. It aimed to identify and study α-decay chains of isotopes of element Z = 115. Experimental data, including the 30 identified chains, were analyzed self-consistently with a virtually constructed spectroscopic setup using GEANT4. A workaround which allows for the use of this simulation toolkit for elements Z > 100 is presented. The interpretation of the real experimental data, i.e. the derived decay schemes of some of heaviest man-made atomic nuclei, crucially depends on the cross check with the virtual "GEANT4 spectroscopy" experiment.

Nuclear spectroscopy with Geant4

“…The -photon coincidence efficiency of the simulation is notably very well under control, because the yield of the 351-keV line in the photon energy spectrum is nicely reproduced using a normalization factor identical to the one of the particle spectrum [12].…”

“…to convert Z = 115 to Z = 99 and Z = 113 to Z = 97, in their atomic properties and study their decay on a stepby-step basis as this method allows most dynamic aspects of the ions to be simulated [12]. Other approaches have ignored the atomic relaxation but allowed hard-coded decay paths covering only rays and conversion electrons using the electron binding energies of the heaviest available atom in Geant4, Fm (Z = 100) [13].…”

Nuclear structure notes on element 115 decay chains

“…Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: [19,26] using the proposed decay schemes in panels (e)-(g) as input. The main features of the decay schemes are highlighted in green.…”

“…Figure 1(d) and Table 1) nor energy-time correlations point to more than one decaying state of 288 115. Feeding the proposed decay scheme of 288 115 shown in Figure 2(e) into the comprehensive TASISpec Geant4 simulations [19,26] results in the green-shaded background displayed in Figure 2(a). This normalized green distribution of 10000 simulated decay events is to be compared with the experimental black curve.…”

Nuclear spectroscopy with Geant4: Proton and neutron emission & radioactivity

“…Such a combination provides an unprecedented high-resolution particle-photon coincidence efficiency [12] and at the same time sufficient granularity for decay studies. Furthermore, TASISpec exists in virtual Geant4 space [14,15]. This allows for a self-consistent cross check of the decay schemes derived from the experimental spectra.…”