No abstract

The new proton radioactivities 165,166,167 Ir and 171 Au have been observed. The Ir isotopes were produced via the 92 Mo( 78 Kr,pxn) 165,166,167 Ir reactions at 357 and 384 MeV. 171 Au was produced via the 96 Ru( 78 Kr,p2n) 171 Au reaction at 389 MeV. The proton emitters were each identified by position, time, and energy correlations between the implantation of a residual nucleus into a double-sided silicon strip detector, the observation of a decay proton, and the subsequent observation of a decay alpha particle from the daughter nucleus ͑ 164,165,166 Os and 170 Pt, respectively͒. Both 166 Ir and 167 Ir have proton-emitting ground and isomeric states, which also decay by alpha emission. The proton-decay rates have been reproduced by calculations using the WKB barrier penetration approximation and a low-seniority shell-model calculation of the spectroscopic factors. The alpha decays of the four nuclei are followed by chains of alpha decays, allowing the determination of single-particle orbital orderings. Mass information has also been obtained from the alpha-decay chains because a connection to a known mass can be obtained for one of the nuclei. Ground-state mass excesses are reported for 151 Tm, 154 Yb, 155 Lu, 158 Hf, 159 Ta, 162 W, 163 Re, 166 Os, 167 Ir, and 170 Pt. The mass excess for 171m Au is also given. Proton separation energies are also deduced for the odd-Z alpha daughter nuclei of the Ir proton emitters.

No abstract

The Phase-Imaging Ion-Cyclotron-Resonance (PI-ICR) technique has been commissioned at the JYFLTRAP double Penning trap mass spectrometer. This technique is based on projecting the ion motion in the Penning trap onto a position-sensitive multichannel-plate ion detector. Mass measurements of stable 85 Rb + and 87 Rb + ions with well-known mass values show that relative uncertainties ∆m/m ≤ 7 · 10 −10 are possible to reach with the PI-ICR technique at JYFLTRAP. The significant improvement both in resolving power and in precision compared to the conventional Time-of-Flight Ion Cyclotron Resonance technique will enable measurements of close-lying isomeric states and of more exotic isotopes as well as ultra-high precision measurements required, e.g., for neutrino physics. In addition, a new phase-dependent cleaning method based on the differences in the accumulated cyclotron motion phases has been demonstrated with short-lived 127 In + and 127m In + ions.

In this article a comprehensive description and performance of the double Penning trap setup JYFLTRAP will be detailed. The setup is designed for atomic mass measurements of both radioactive and stable ions and additionally serves as a very high resolution mass separator. The setup is coupled to the IGISOL facility at the accelerator laboratory of the University of Jyväskylä. The trap has been online since 2003 and it was shut down in summer 2010 for relocation to upgraded IGISOL facility. Numerous atomic mass and decay energy measurements have been performed using the time-of-flight ion-cyclotron resonance technique. Also the trap has been used in several decay spectroscopy experiments as a high-resolution mass filter.

No abstract

No abstract

The laser ion source project at the IGISOL facility, Jyväskylä, has motivated the development and construction of an rf sextupole ion beam guide (SPIG) to replace the original skimmer electrode. The SPIG has been tested both off-line and on-line in protoninduced fission, light-ion and heavy-ion induced fusion-evaporation reactions and, in each case, has been directly compared to the skimmer system. For both fission and light-ion induced fusion, the SPIG has improved the mass-separated ion yields by a factor of typically 4 to 8. Correspondingly, the transmission efficiency of both systems has been studied in simulations with and without space charge effects. The transport capacity of the SPIG has been experimentally determined to be ∼10 12 ions s −1 before space charge effects start to take effect. A direct comparison with the simulation has been made using data obtained via light-ion fusion evaporation. Both experiment and simulation show an encouraging agreement as a function of current extracted from the ion guide.