Development of a surface ionization source for the production of radioactive alkali ions in SPIRAL

C. Eléon (1) , P. Jardin (1) , G. Gaubert (1) , M.G. Saint-Laurent (1) , J.A. Alcantara-Nunez (1) , R. Alves Condé (1) , C. Barué (1) , D. Boilley (1, 2) , J. Cornell (1) , P. Delahaye (3) , M. Dubois (1) , B. Jacquot (1) , P. Lehérissier (1) , R. Leroy (1) , G. Lhersonneau (1) , M. Marie-Jeanne (3) , L. Maunoury (4) , J.Y. Pacquet (1) , F. Pellemoine (1) , C. Pierret (4) , J.C. Thomas (1) , A.C.C. Villari (1)

1 GANIL - Grand Accélérateur National d'Ions Lourds
2 UNICAEN - Université de Caen Normandie
3 CERN - European Organization for Nuclear Research
4 CIRIL - Centre Interdisciplinaire de Recherche Ions Lasers

In the framework of the production of radioactive alkali ion beams by the isotope separator on-line (ISOL) method in SPIRAL, a surface ionization source has been developed at GANIL to produce singly-charged ions of Li, Na and K. This new source has been designed to work in the hostile environment found at SPIRAL whilst having a long lifetime. This new system of production has two ohmic heating components: the first for the target oven and the second for the ionizer. The latter, being in carbon, offers high reliability and competitive ionisation efficiency. This new surface ionization source has been tested on line using a 48Ca primary beam at 60,3A MeV with an intensity of 0,14 pµA. The ionization efficiencies obtained for Li, Na and K are significantly better than the theoretical values calculated using the known Langmuir surface ionisation equation. Moreover, the design of the ion source avoids the cavity effects reported by Kirchner. The enhanced efficiency can be understood by considering a particular effect related to the polarization of the ionizer. This feature is shown to be extremely important also for short-lived isotopes. In the future, this source will be associated with the multicharged electron-cyclotron-resonance (ECR) ion source NANOGAN III for production of multicharged alkali ions in SPIRAL. The preliminary tests of the setup for the production of multicharged alkali ions will also be presented in this contribution.

Mots clés: 1+ to N+ method; 1+ ion beam; target ion source system; charge breeding

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

C. Eléon, P. Jardin, G. Gaubert, M.G. Saint-Laurent, J.A. Alcantara-Nunez, et al.. Development of a surface ionization source for the production of radioactive alkali ions in SPIRAL. XVth International Conference on Electromagnetic Isotope Separators and Techniques related to their Applications (EMIS2007), Jun 2007, Deauville, France. pp.4362-4367, ⟨10.1016/j.nimb.2008.05.067⟩. ⟨in2p3-00159393⟩