0000000000728886
AUTHOR
O. Engels
Space-Charge Effects with REXTRAP
The beam quality of radioactive ion beams produced by present target ion source technology is often not sufficient for direct post-acceleration. Furthermore, pulsed beams insure a more efficient use of an accelerator. In the case of REX-ISOLDE, the post accelerator at the CERN ISOLDE facility, a gas-filled Penning trap (REXTRAP) has been chosen for accumulation of the radioactive ions and conversion into cooled bunches. Radial centering of the ions is achieved by applying an rf field with a frequency equal to the cyclotron frequency of the desired ion species. The efficiency achieved in the first tests with different isotopes covering nearly the entire mass range was already >20%. Going to …
Accurate masses of neutron-deficient nuclides close to
Abstract Mass measurements with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN are extended to nonsurface ionizable species using newly developed ion-beam bunching devices. Masses of 179–197Hg, 196,198Pb, 197Bi, 198Po and 203At were determined with an accuracy of 1×10 −7 corresponding to δm≈20 keV. Applying a resolving power of up to 3.7×10 6 ground and isomeric states of 185,187,191,193,197Hg were separated. First experimental values for the isomeric excitation energy of 187,191Hg are obtained. A least-squares adjustment has been performed and theoretical approaches are discussed to model the observed fine structure in the binding energy.
SHIPTRAP—a capture and storage facility for heavy radionuclides at GSI
Abstract SHIPTRAP will be an ion-trap facility for heavy radionuclides delivered from SHIP. Ion traps are a perfect instrument for precision measurements since the ions can be cooled to an extremely small phase space and can be stored for a very long time. In addition one can achieve very high purity by removing contaminant ions. SHIPTRAP will extend the possibilities of measurements in traps to transuranium nuclides and provide cooled and isobarically pure ion bunches.
Status of the SHIPTRAP Project: A Capture and Storage Facility for Heavy Radionuclides from SHIP
The ion trap facility SHIPTRAP is being set up to deliver very clean and cool beams of singly-charged recoil ions produced at the SHIP velocity filter at GSI Darmstadt. SHIPTRAP consists of a gas cell for stopping and thermalizing high-energy recoil ions from SHIP, an rf ion guide for extraction of the ions from the gas cell, a linear rf trap for accumulation and bunching of the ions, and a Penning trap for isobaric purification. The progress in testing the rf ion guide is reported. A transmission of about 93(5)% was achieved.
Mass measurements on unstable Sn and Sr isotopes with the ISOLTRAP mass spectrometer
Direct mass measurements have been performed on the isotopes 76,77,80,81Sr and 129,130,131,132Sn by means of the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. In the case of 76Sr the mass was measured for the first time and an accuracy of about 30 keV was reached (Fig. 1). The masses of the tin isotopes are known for a long time from Q β measurements.