0000000000263975
AUTHOR
Sönke Beck
Multi-nucleon transfer reactions at ion catcher facilities : a new way to produce and study heavy neutron-rich nuclei
Abstract The production of very neutron-rich nuclides heavier than fission fragments is an ongoing experimental challenge. Multi-nucleon transfer reactions (MNT) have been suggested as a method to produce these nuclides. By thermalizing the reaction products in gas-filled stopping cells, we can deliver them as cooled high-quality beams to decay, laser and mass spectrometry experiments. High precision mass spectrometry will allow for the first time to universally and unambiguously identify the atomic and proton numbers of the ions produced in MNT reactions. In this way their ground and isomeric state properties can be studied in high-precision measurements. In experiments at IGISOL, Finland …
The science case of the FRS Ion Catcher for FAIR Phase-0
The FRS Ion Catcher at GSI enables precision experiments with thermalized projectile and fission fragments. At the same time it serves as a test facility for the Low-Energy Branch of the Super-FRS at FAIR. The FRS Ion Catcher has been commissioned and its performance has been characterized in five experiments with 238U and 124Xe projectile and fission fragments produced at energies in the range from 300 to 1000 MeV/u. High and almost element-independent efficiencies for the thermalization of short-lived nuclides produced at relativistic energies have been obtained. High-accuracy mass measurements of more than 30 projectile and fission fragments have been performed with a multiple-reflection…
Mass measurements of As, Se, and Br nuclei, and their implication on the proton-neutron interaction strength toward the N=Z line
Mass measurements of the $^{69}$As, $^{70,71}$Se and $^{71}$Br isotopes, produced via fragmentation of a $^{124}$Xe primary beam at the FRS at GSI, have been performed with the multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) of the FRS Ion Catcher with an unprecedented mass resolving power of almost 1,000,000. For the $^{69}$As isotope, this is the first direct mass measurement. A mass uncertainty of 22 keV was achieved with only 10 events. For the $^{70}$Se isotope, a mass uncertainty of 2.6 keV was obtained, corresponding to a relative accuracy of $\delta$m/m = 4.0$\times 10^{-8}$, with less than 500 events. The masses of the $^{71}$Se and $^{71}$Br isotopes were measured…
Studying Gamow-Teller transitions and the assignment of isomeric and ground states at $N=50$
Direct mass measurements of neutron-deficient nuclides around the N=50 shell closure below $^{100}$Sn were performed at the FRS Ion Catcher (FRS-IC) at GSI, Germany. The nuclei were produced by projectile fragmentation of $^{124}$Xe, separated in the fragment separator FRS and delivered to the FRS-IC. The masses of 14 ground states and two isomers were measured with relative mass uncertainties down to 1×10−7 using the multiple-reflection time-of-flight mass spectrometer of the FRS-IC, including the first direct mass measurements of $^{98}$Cd and $^{97}$Rh. A new QEC=5437±67 keV was obtained for $^{98}$Cd, resulting in a summed Gamow-Teller (GT) strength for the five observed transitions (0+…