SMI-06 Workshop, Groningen, 27-28.03.2006 Systematic comparison of ISOLDE-SC yields with calculated in-target production rates SMI-06 Workshop, Groningen, 27-28.03.2006 S. Lukić GSI - Darmstadt s.lukic@gsi.de

SMI-06, March 27-28, Groningen S. Lukić Outline Motivation ISOLDE SC yield database In-target production Results of the comparison Conclusions SMI-06, March 27-28, Groningen S. Lukić

SMI-06, March 27-28, Groningen S. Lukić Motivation Future ISOL facility projects (EURISOL, SPIRAL2, RIA) Nuclide production optimization Optimal nuclear reaction Target and ion-source development Need for beam intensity predictions in various scenarios Nuclear reaction data and models Extraction-efficiency prediction SMI-06, March 27-28, Groningen S. Lukić

SMI-06, March 27-28, Groningen S. Lukić Motivation Isotope Separation OnLine – nuclide production in a thick target + extraction and mass separation Part of the produced nuclei is lost to: Sticking to walls Escaping ionization Chemical reactions Radioactive decay All these losses are difficult to directly estimate. Their overall effect can be deduced from a comparison of the final yields with the in-target production rates SMI-06, March 27-28, Groningen S. Lukić

ISOLDE SC yield database At ISOLDE, isotopic yields for 64 different elements were documented during its operation with the SC proton beam in CERN (196? – 1992) H.-J. Kluge, ISOLDE User's Guide, CERN 86-05, http://isolde.web.cern.ch/ISOLDE/ SMI-06, March 27-28, Groningen S. Lukić

ISOLDE SC yield database Yield uncertainties because of isobaric and molecular contaminations In general, the accuracy is estimated to be within a factor of 2-3 close to stability, and up to one order of magnitude far-off stability H.-J. Kluge, ISOLDE User's Guide, CERN 86-05, http://isolde.web.cern.ch/ISOLDE/ SMI-06, March 27-28, Groningen S. Lukić

In-target production

In-target production Experimental data Cross-section data in inverse kinematics in GSI Wide range of colliding systems (Fe – U / p – Pb) Wide range of energies (300 – 1000 A MeV) SMI-06, March 27-28, Groningen S. Lukić

In-target production - ABRABLA 238U + p @ 1 A GeV Reaction simulation code Benchmarked against GSI data Complex physics, high predictive power SMI-06, March 27-28, Groningen S. Lukić

In-target production – thick target Energy loss – mean value of xs used Beam attenuation Secondary reactions – low-energy fission – comparison with exp. data SMI-06, March 27-28, Groningen S. Lukić

Results

SMI-06, March 27-28, Groningen S. Lukić Results – francium Non-uniform dependence of half-lives with the mass number Clear correlation of the extraction efficiency with the half-life SMI-06, March 27-28, Groningen S. Lukić

SMI-06, March 27-28, Groningen S. Lukić Results – francium Same general behavior in many different cases: Constant efficiency for long half-lives Power-function behavior for short half-lives Parameterization: SMI-06, March 27-28, Groningen S. Lukić

Results – more examples SMI-06, March 27-28, Groningen S. Lukić

Results – saturation efficiency for different groups SMI-06, March 27-28, Groningen S. Lukić

Results – α parameter across the solid targets Theoretical value: 1.5 U. Köster, PhD Thesis, Munich Technical University (2000) SMI-06, March 27-28, Groningen S. Lukić

Results – uncertainties Uncertainties come from: difficulties to precisely calculate cross sections at the steep outer slopes of isotopic distributions far off stability isobaric and molecular contaminations of ISOLDE beams side feeding unknown fraction of nuclides of a certain type that are produced in isomeric states Sometimes, these effects are so large that... SMI-06, March 27-28, Groningen S. Lukić

Results – cases that "don't work" In ~30% of cases, no apparent correlation of efficiencies with half-lives SMI-06, March 27-28, Groningen S. Lukić

SMI-06, March 27-28, Groningen S. Lukić Conclusions Measured ISOLDE yields have been compared with new and high-quality information on the nuclide-production cross sections in proton-induced reactions. Essential properties of the overall ISOL efficiencies have been quantified for a wide variety of isotopic chains from different target and ion-source systems. : The parameter εs – extraction efficiency in the limit of long half-lives – directly indicates the overall losses that occur apart from the decay losses. The parameters t0 and α describe the effect of the decay losses with short half-lives This information helps in completing our understanding of the efficiencies of the ISOL method, as well as in identifying the issues that need most attention in the process of ISOL target and ion-source development This kind of study is, in principle, applicable across the entire table of elements and for all target and ion-source systems. SMI-06, March 27-28, Groningen S. Lukić

SMI-06, March 27-28, Groningen S. Lukić Acknowledgment Co-authors: F. Gevaert, A. Kelić, M.V. Ricciardi, K.-H. Schmidt, O. Yordanov We are grateful to Ulli Köster for very helpful remarks and discussion about specific ISOLDE data points We acknowledge the financial support of the European Community under the FP6 “Research Infrastructure Action – Structuring the European Research Area”, EURISOL DS Project, contract no. 515768 RIDS. The EC is not liable for any use that may be made of the information contained herein. SMI-06, March 27-28, Groningen S. Lukić

Thank you!