Speaker
Description
The double Penning-trap mass spectrometer JYFLTRAP [1] at IGISOL [2] has been recently used to measure the masses of neutron-rich Fe, Co, Ni, Cu, and Zn isotopes. The masses of these nuclei close to the Z=28 and N=50 closed shells are relevant for understanding the nuclear structure far from stability but also for the studies of core-collapse supernovae. Electron captures play a key role during the collapse stage of supernovae [3] as they reduce the electron gas pressure, cool the core via neutrino emission and drive matter to more neutron-rich nuclei. To calculate the composition of matter in a core-collapse supernova, extended Nuclear Statistical Equilibrium (NSE) models can be used. One of the key parameters for the NSE calculations is the nuclear binding energy [4]. According to recent studies, the binding energies and electron capture rates on nuclei situated in the vicinity of the N=50 shell closure have a high impact on core-collapse simulations [5]. Data for the isotopes located close to Z=28 and N=50 are also important for understanding the nuclear structure close to $^{78}$Ni [6].
The ions of interest were produced by 35 MeV proton-induced fission on a uranium target at IGISOL. Over the 11 nuclides measured during the one week of experiment, five were measured for the first time. The measurements were mainly done using the time-of-flight ion-cyclotron resonance technique (TOF-ICR) [7]. In addition, the novel PI-ICR technique [8] was used for some cases to identify long-living isomeric states. In this contribution, I will describe the experimental method and preliminary results from the experiment.
References
- T. Eronen et al., Eur. Phys. J. A 48 (2012) 46.
- I. Moore et al., Nucl. Instrum. Methods Phys. Res. B 317, 208 (2013).
- K. Langanke et al., Nuclear Physics A 928 (2014) 305–312.
- F. Gulminelli and Ad. R. Raduta, PRC 92 (2015) 055803.
- C. Sullivan et al., ApJ, 816 (2015) 44.
- M.-G. Porquet and O. Sorlin, Phys. Rev. C 85 (2012) 014307.
- M. König et al., Int. J. Mass Spectrom. Ion Process. 142 (1995) 95.
- S. Eliseev and al., Phys. Rev. Lett. 110 (2013) 082501.
