TASISpec—A highly efficient multi-coincidence spectrometer for nuclear structure investigations of the heaviest nuclei

Abstract

TASISpec (TASCA in Small Image mode Spectroscopy) combines composite Ge-and Si-detectors for a new detector setup aimed towards multi-coincidence γ-ray, X-ray, conversion electron, fission fragment, and α-particle spectroscopy of the heaviest nuclei. It exploits the TASCA separator's unique small image focal mode, i.e. the fact that evaporation residues produced in fusion-evaporation reactions can be focused into an area of less than 3 cm in diameter. This provides the possibility to pack detectors in very close geometry, resulting in an unprecedented detection efficiency of radioactive decays in prompt and delayed coincidence with implanted nuclei.

Selected spectroscopic results on element 115 decay chains

“…The fusion-evaporation residues were focused towards the TASISpec radiation detector system [24] positioned at the focal plane of TASCA. On the order of 100 charged particles per second reached the 32 × 32-strip double-sided silicon strip DSSSD implantation detector, which is 6 × 6 cm 2 in area and 0.52 mm thick and visible in the photograph of the 'open' TASISpec in Fig.…”

“…In several publications, more details can be found on the preparations of our experiment [28,29], its set-up [24], the experiment itself [19,25], data analysis procedures [26] as well as discussions related to the remaining 30 − 22 = 8 chains also associated with isotopes of element Z = 115 [25]. Monte-Carlo simulations [panels (a)-(c)] using the corresponding proposed decay schemes displayed in Fig.…”

First superheavy element experiments at the GSI recoil separator TASCA: The production and decay of element 114 in thePu244(CaGates1, Düllmann2, Schädel3 et al. 2011Phys. Rev. CSelf Cite1598780View full textAdd to dashboardCite

“…Decay properties of [252][253][254] No include α-decay, spontaneous fission (SF), and electron capture branches, allowing for the characterization of the detection and data acquisition system using multiple different decay scenarios. In addition, α-decays of 253 No are in prompt coincidence with three intense γ-lines [16], ideal for testing TASCA's ability to be used in nuclear structure studies [17].…”

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“…The dipole was set to guide ions with magnetic rigidities of ∼ 2.1 Tm to the focal plane. The implantation DSSSD of TASISpec comprises 32 strips on the p-side, facing the incoming beam, and 32 n-side strips [5]. The detector was calibrated using an external 4-line α source.…”

“…Here, the multi-coincidence detector setup TASISpec (TASCA in Small Image Mode Spectroscopy) [5] will be used, in which nuclei are implanted into a 5.9 cm × 5.9 cm double-sided silicon strip detector (DSSSD). Subsequent decay radiation is recorded in this, in surrounding DSSSDs, and in composite Ge detectors.…”