Search

We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report.

Excited states have been identified in the very neutron-deficient 112Xe nucleus. The ground-state band has been observed up to spin 12 ℏ, and a negative-parity side band has been observed up to 13 ℏ. The bands have been assigned to 112Xe by detecting gamma rays in coincidence with evaporated charged particles and neutrons. The energy of the 2+1state in 112Xe is lower than would be expected from both calculations and from systematics of the neighboring xenon isotopes, which indicates a larger than expected ground-state deformation. The observations of a low-lying 3−state and large deduced B(E1) values are suggestive of increased octupole correlations, which may explain the apparently large ground-state deformation. Constrained Hartree–Fock+BCS calculations have been performed which show qualitative agreement with the trend in deformation of the very neutron-deficient xenon isotopes.

Abstract:: High-spin states in the 96Tc nucleus have been studied with the reactions 82Se(19F,5nγ) at 68 MeV and Zn(36S,αpxn) at 130 MeV. Two γ-ray cascades (irregular bandlike structures) have been observed up to an excitation energy of about 10 MeV and spin 21-22?.

High-spin states have been studied in 128Ce, produced in the 100Mo(32S,4n) reaction, using the Euroballγ-ray spectrometer. A quadruples analysis (γ4) of the data has extended several bands to high spin. Systematics of quasiparticle alignments in cerium isotopes and relevant isotonic chains are discussed and compared to Woods–Saxon cranking calculations.

High-spin states have been populated in 54117Xe via the 90Zr(31P, p3n) reaction at 150 MeV, using the EUROGAM II γ-ray spectrometer to record high-fold γ-ray coincidences. Although 117Xe accounts for only 20% of the total fusion cross-section, a high-fold (γ4) analysis of this weak channel has significantly extended the level scheme. In particular, the νh112 yrast band has been extended to Iπ = (912−) and shows features which are consistent with those of smooth band termination at high spin. The high-spin behaviour of 117Xe is discussed within the framework of cranked Nilsson-Strutinsky calculations. In addtion, measured B(E1) strengths are discussed in terms of possible octupole correlations in this mass region.

Abstract.: High spin states of 101Rh have been populated using the reaction 70Zn+36S at 130 MeV. γ-rays were detected with the EUROGAM2 array. New high-spin bands have been observed in this nucleus up to 45/2−, 57/2− and 65/2+ states. They have been interpreted using the Nilsson-Strutinsky cranking formalism as terminating configurations. Two of the bands were observed up to the predicted terminating states which are built up from g9/2 protons as well as d5/2, g7/2 and h11/2 neutrons relative to a 90Zr core.

Abstract:: The low-spin band structure of neutron-deficient 11554Xe has been studied following a low-energy (212.3 MeV) 60Ni(58Ni,2pnγ) reaction performed at IReS, Strasbourg, with the Garel+ spectrometer. The relative excitation energies of νh11/2 (isomeric), νg7/2, and νd5/2 bandheads have been established.

Abstact: High spin states of ¹⁰⁰Rh have been populated using the reaction ⁷⁰Zn+³⁶S at 130 MeV. -rays were detected with the EUROGAM2 array. The level structure of ¹⁰⁰Rh has been extended up to 14.41 MeV excitation energy. Several band structures are observed. A band based on a I=8 state is developed up to the I=24 level. It is assigned as the g_9/2⁵h_11/2 configuration.