Online test of the FRS Ion Catcher at GSI

At the FRS Ion Catcher at GSI, relativistic exotic ions produced by projectile fragmentation/fission are range-focused, slowed down and thermalised in a gas-filled stopping cell, extracted and made available to high-precision experiments with ions almost at rest. It is a prototype for a gas cell system at the Low-Energy Branch of the Super-FRS at FAIR. In an online experiment, the FRS Ion Catcher was commissioned successfully with relativistic nickel fragments. The overall efficiency of the system was measured as (1.8 ± 0.3)% and can be divided into a stopping efficiency of (5.0 ± 1.1)% and an extraction and transport efficiency of (35.8 ± 9.4)%. The overall efficiency is hence limited mostly by the stopping efficiency, which could be increased in the future by operating at higher gas cell pressures. From extraction time measurements of polyatomic ions formed in the gas cell extraction times of atomic ions of 20–50 ms can be derived. The potential of the system was illustrated by the half-life measurement of 54Co with a short half-life of 193 ms only.status: publishe

Study of dipole excitations and the single particle structure of neutron rich Ni isotopes

An experiment was performed using the FRS-LAND setup at GSI to study the dipole strength distributions above neutron separation threshold for neutron-rich Ni isotopes. Measurements, using the same experimental setup, were also carried out to extract single particle occupancies via knockout reactions to investigate the structure and magicity of the neutron-rich Ni isotopes. The status of the data analysis and preliminary results are presented

Fecundity of Baltic cod: temporal and spatial variation

Potential and relative potential fecundity of 701 cod Gadus morhua caught in the Bornholm Basin (ICES Sub-division 25) during 1987–1996 and 106 from the Gdansk Deep (ICES Sub-division 26) in 1995 and 1996 varied significantly between years but neither between different spawning grounds nor between different sampling months within one spawning season. Growth and water temperature are factors identified to influence the mean relative fecundity explaining 66% of the variance between years