[en] The ion guide isotope separator facility IGISOL of the University of Jyvaeskylaehas been moved to the new K-130 heavy ion cyclotron laboratory. The totally reconstructed facility is described in detail. The primary beams and targets, helium pumping, separator beam line construction and separator beam diagnostics are discussed. The spectroscopy stations are introduced with illustrative examples from the research program, including beta-delayed proton and neutron spectroscopy, gamma-ray spectroscopy with and without arrays, conversion electron spectroscopy, collinear laser spectroscopy and nuclear level lifetime spectroscopy. (orig.)

[en] Yields of fission products have been studied at the recently upgraded IGISOL facility in Jyvaeskylaeusing 50 MeV H⁺₂ beam (E_p=25 MeV) and thin ^natTh and ^natU targets. The independent yields of fission products in the mass regions A=99-112 (elements Y, Nb and Tc) and A=127-134 (elements Sn, Sb and Te) have been obtained. Comparisons of the experimental isotopic distributions with theoretical ones are presented. Enhancement of the production rate of the doubly magic ¹³²Sn is observed in the experimental yield curve. (orig.)

[en] The nuclear structure studies performed since 1994 at the IGISOL online mass separator in Jyvaeskylae are reviewed and prospects for future studies are mentioned briefly

[en] By using the IGISOL technique, adapted for the study of products of heavy ion induced fusion-evaporation reactions, it has been possible to identify a new isomer in the mass chain A = 125. (author)

[en] Presently, the Jyvaeskylae IGISOL facility delivers mass-separated beams of fission products with an intensity of 2700 ions/s per mb cross section. A further increase in yield is expected from the ongoing investigations into improving the design and understanding better the behavior of the fission ion guide. The study of new neutron-rich nuclei is hindered by the presence of different kinds of contaminants in the mass-separated beam: isobaric isotopes, isotopes of neighboring masses and doubly-charged ions. These problems will be solved by producing isotopically pure beams. We are developing an ion beam cooler+ion trap combination for this purpose

[en] Levels in ⁹⁹Zr populated by β decay of on-line mass separated ⁹⁹Y have been studied by γ-ray spectroscopic methods, including γ-γ coincidences recorded with an array of ten Ge detectors and level-lifetime measurements. The formerly reported strongly collective character of the 53-keV transition turns out to be questionable. This implies a revision of the experimental evidence for shape coexistence in ⁹⁹Zr. Transition rates and γ-ray branching ratios make a new level at 679 keV with t_1/2=9 ns another candidate for a deformed state. copyright 1997 The American Physical Society

[en] For more than 10 years, neutron-rich nuclei produced in light-ion induced fission have been studied at the Ion Guide Isotope Separator On-Line (IGISOL) facility of the Department of Physics, University of Jyvaeskylae. The present performance of the system is briefly discussed. Some recent results concerning superasymmetric fission and β-delayed neutron emission are presented. The plans for producing isotopically pure beams are summarized

[en] The ground state magnetic dipole moment of ⁹C has been remeasured using the β-NMR technique and our new value of 1.396(3)μ_N is in agreement with the previously measured value for this nuclide. The quenched magnetic moment of ⁹C and the anomalously large isoscalar spin expectation value for the ⁹C-⁹Li T=3/2 mirror pair compare favorably with the results of shell model calculations employing isospin nonconserving (INC) interactions. The ground state magnetic moment of ²¹Mg was also investigated to determine the significance of INC effects in the heavier A=21 T=3/2 mirror system

[en] Very neutron-rich fission products of the mass chain A=113 obtained from the IGISOL on-line mass separator have been investigated by γγ coincidence techniques and γ-spectra multiscaling. Gamma-rays following β-decay of ¹¹³Tc have been observed for the first time and a new 0.5 s isomeric state has been found in ¹¹³Ru. (orig.)

[en] The level properties near the stable doubly-magic nuclei formed the experimental grounds for the theoretical description of nuclear structure. However with a departure from the beta-stability line, the classical well-established shell structure might be modified. In particular, it may even vanish for extremely exotic neutron-rich nuclei near the neutron-drip line. Presently, it is impossible to verify such predictions by a direct experimental studies of these exotic objects. However, one may try to observe and understand the evolution of the nuclear structure while departing in the experiment as far as possible from the stable nuclei. An extension of experimental nuclear structure studies towards the nuclei characterized by high neutron excess is crucial for such verifications as well as for the τ-process nucleosynthesis scenario. Heavy neutron-rich nuclei, south-east of doubly-magic ²⁰⁸Pb, were always very difficult to produce and investigate. The nuclei like ²¹⁸Po and ²¹⁴Pb or ²¹⁰Tl marked the border line of known nuclei from the beginning of the radioactivity era for over ninety years. To illustrate the difficulties, one can refer to the experiments employing the on-line mass separator technique. A spallation of heavy targets like ²³²Th and ²³⁸U by high-energy protons was proven as a source of heavy neutron-rich nuclei. The isotopes near and beyond doubly-magic ²⁰⁸Pb were produced too. However, such studies often suffered from an isobaric contamination of much more strongly produced and efficiently released elements like francium or radon and their decay products. A new experimental technique, based on the pulsed release element selective method recently developed at the PS Booster-ISOLDE at CERN [7,8,9] greatly reduces the contamination of these very short-lived α-emitters (Z ge 84) for the isobaric mass chains A=215 to A=218