Reaction mechanisms involved in the production of neutron-rich isotopes

The reaction mechanisms best suited for the production of neutron-rich nuclei, fragmentation and fission, are discussed. Measurements of the production cross sections of reaction residues together with model calculations allow to conclude about the expected production rates of neutron-rich isotopes in future facilities.Comment: 9 pages, 8 figures Proceedings of the Third International Conference on Fission and Properties of Neutron-Rich Nuclei November 3-9, 2002, Sanibel Island, Florida, US

Model calculations of a two-step reaction scheme for the production of neutron-rich secondary beams

A two-step reaction scheme for the production of extremely neutron-rich radioactive beams, fission followed by cold fragmentation, is considered. The cross sections of the second step, the cold fragmentation of neutron-rich fission fragments, are estimated with different computer codes. Discrepancies between an empirical systematics and nuclear-reaction codes are found.Comment: 31 pages, 13 figures, background information on http://www-wnt.gsi.de/kschmidt

Production of neutron-rich nuclei in fragmentation reactions of 132Sn projectiles at relativistic energies

The fragmentation of neutron-rich 132Sn nuclei produced in the fission of 238U projectiles at 950 MeV/u has been investigated at the FRagment Separator (FRS) at GSI. This work represents the first investigation of fragmentation of medium-mass radioactive projectiles with a large neutron excess. The measured production cross sections of the residual nuclei are relevant for the possible use of a two-stage reaction scheme (fission+fragmentation) for the production of extremely neutron-rich medium-mass nuclei in future rare-ion-beam facilities. Moreover, the new data will provide a better understanding of the "memory" effect in fragmentation reactions.Comment: 5 pages, 3 figure

Fragmentation of exotic oxygen isotopes

Abrasion-ablation models and the empirical EPAX parametrization of projectile fragmentation are described. Their cross section predictions are compared to recent data of the fragmentation of secondary beams of neutron-rich, unstable 19,20,21O isotopes at beam energies near 600 MeV/nucleon as well as data for stable 17,18O beams

Production of a C-15 radioactive ion beam based on O-18(n, alpha)

.In the context of the SPIRAL2 radioactive beam facility the production rate of the neutron-rich C-15 nucleus by O-18(n,) has been investigated. In a water target of 20 cm(3), enriched in O-18 and placed behind the neutron converter, a rate of a few 10(10) nuclei per second can be reached with 1mA of 40MeV deuterons. A O-18(n,) cross-section based on the activation method is proposed. It is intermediate between the highest and lowest evaluations available to date.Peer reviewe

Intruder bands and configuration mixing in the lead isotopes

A three-configuration mixing calculation is performed in the context of the interacting boson model with the aim to describe recently observed collective bands built on low-lying $0^+$ states in neutron-deficient lead isotopes. The configurations that are included correspond to the regular, spherical states as well as two-particle two-hole and four-particle four-hole excitations across the Z=82 shell gap.Comment: 20 pages, 4 figures, accepted by PRC, reference added for section 1 in this revised versio

Measurement of residual nucleus cross sections and recoil energies in p + Fe collisions at 300, 500, 750, 1000 and 1500 MeV

The production of residual nuclei in p + Fe collisions has been measured at GSI on the FRS facility by means of the reverse kinematic techniques at 300, 500, 750, 1000 and 1500 MeV/A. The cross-sections larger than 0.01 mb of all isotopes with Z larger than 8 have been obtained. Velocity distributions were also measured. Comparisons to models describing spallation reactions and some empirical formulae often used in astrophysics are presented. These data are directly used to calculate impurety production and DPAs in a thin window as foreseen in spallation sources or accelerator-driven systems

Analysis of H-3, Cl-36, Ba-133, Cs-134 and Na-22 from synthetic granitic groundwater : an in situ through diffusion experiment at ONKALO

A method for analyzing H-3, Cl-36, Na-22, Ba-133 and Cs-134 from simulated groundwater (SGW) samples was introduced. Gamma emitting radionuclides Na-22, Ba-133 and Cs-134 were measured by using an HPGe-detector. Beta emitting H-3 and Cl-36 were separated from gamma emitting Na-22, Ba-133 and Cs-134. AgCl precipitation was used for the separation of Cl-36 from SGW samples with yields of 98 +/- 2%. H-3 was separated by distillation with recoveries of 97 +/- 3%. This method was used for the determination of activity concentrations of H-3, Cl-36, Na-22, Ba-133 and Cs-134 in SGW samples collected from an in situ through diffusion experiment.Peer reviewe