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Charge breeder electron cyclotron resonance ion sources (CB-ECRIS) are used as 1+ →n+ charge multiplication devices of post-accelerated radioactive ion beams. The charge breeding process involves thermalization of the injected 1+ ions with the plasma ions in ionion collisions, subsequent ionization by electron impact and extraction of the n+ ions. Charge breeding experiments of 85 Rb and 133 Cs ion beams with the 14.5 GHz PHOENIX CB-ECRIS operating with oxygen gas demonstrate the plasma diagnostics capabilities of the 1+ injection method. Two populations can be distinguished in the m/q-spectrum of the extracted ion beams, the low (1+ and 2+) charge states representing the uncaptured fraction of the incident 1+ ion beam and the high charge states that have been captured in ion-ion collisions and subsequently charge bred through electron impact ionization. Identification of the uncaptured fraction of the 1+ ions allows estimating the lower limit of ion-ion collision frequency of various charge states in the ECRIS plasma. The collision frequencies of highly charged ions (∼10 7 Hz) are shown to exceed their gyrofrequencies (∼10 6 Hz) at least by an order of magnitude, which implies that the dynamics of high charge state ions are dictated by magnetically confined electrons and ambipolar diffusion and only low charge state ions can be considered magnetized. Furthermore, it is concluded that the plasma density of the ECRIS charge breeder is most likely on the order of 10 11 cm −3 i.e. well below the critical density for 14.5 GHz microwaves.

BackgroundRecently, significant interest in 44Sc as a tracer for positron emission tomography (PET) imaging has been observed. Unfortunately, the co-emission by 44Sc of high-energy γ rays (Eγ = 1157, 1499 keV) causes a dangerous increase of the radiation dose to the patients and clinical staff. However, it is possible to produce another radionuclide of scandium—43Sc—having properties similar to 44Sc but is characterized by much lower energy of the concurrent gamma emissions. This work presents the production route of 43Sc by α irradiation of natural calcium, its separation and purification processes, and the labeling of [DOTA,Tyr3] octreotate (DOTATATE) bioconjugate.MethodsNatural CaCO3 and enriched [40Ca]CaCO3 were irradiated with alpha particles for 1 h in an energy range of 14.8–30 MeV at a beam current of 0.5 or 0.25 μA. In order to find the optimum method for the separation of 43Sc from irradiated calcium targets, three processes previously developed for 44Sc were tested. Radiolabeling experiments were performed with DOTATATE radiobioconjugate, and the stability of the obtained 43Sc-DOTATATE was tested in human serum.ResultsStudies of natCaCO3 target irradiation by alpha particles show that the optimum alpha particle energies are in the range of 24–27 MeV, giving 102 MBq/μA/h of 43Sc radioactivity which creates the opportunity to produce several GBq of 43Sc. The separation experiments performed indicate that, as with 44Sc, due to the simplicity of the operations and because of the chemical purity of the 43Sc obtained, the best separation process is when UTEVA resin is used. The DOTATATE conjugate was labeled by the obtained 43Sc with a yield >98 % at elevated temperature.ConclusionsTens of GBq activities of 43Sc of high radionuclidic purity can be obtainable for clinical applications by irradiation of natural calcium with an alpha beam.

The internal α-particle beam of the Warsaw Heavy Ion Cyclotron was used to produce research quantities of the medically interesting Sc radioisotopes from natural Ca and K and isotopically enriched Ca targets. The targets were made of metallic calcium, calcium carbonate and potassium chloride. New data on the production yields and impurities generated during the target irradiations are presented for the positron emittersSc, Sc andSc. The different paths for the production of the long lived Sc/Sc in vivo generator, proposed by the ARRONAX team, using proton and deuteron beams as well as alpha-particle beams are discussed. Due to the larger angular momentum transfer in the formation of the compound nucleus in the case of the alpha particle induced reactions, the isomeric ratio of Sc/Sc at a bombarding energy of 29MeV is five times larger than previously determined for a deuteron beam and twenty times larger than for proton induced reactions on enriched CaCO targets. Therefore, formation of this generator via the alpha-particle route seems a very attractive way to form these isotopes. The experimental data presented here are compared with theoretical predictions made using the EMPIRE evaporation code. Reasonable agreement is generally observed.

The internal alpha particle beam of the heavy ion cyclotron operated by the Heavy Ion Laboratory (HIL) of the University of Warsaw has a maximum energy of 32 MeV and currently an intensity of up to 1 pµA. This beam is used by the HIL-University of Silesia collaboration for the production of research quantities of 211 At, 72 Se/ 72 As and 43,44 Sc radioisotopes. The produced activities are transported to the Institute of Nuclear Chemistry and Technology in Warsaw where research on therapeutic and imaging radiopharmaceuticals based on these radioisotopes is pursued.

Angular distributions of 7 Li + 11 B elastic and inelastic scattering were measured at E lab ( 11 B) = 44 MeV for the transitions to the ground and excited states of 7 Li and 11 B. The present data and data taken from the literature at E lab ( 7 Li) = 34 MeV were analyzed within the optical model and coupled-reaction-channels methods. Elastic and inelastic scattering, reorientations of 7 Li and 11 B, and the most important one-and two-step transfers were included in the channels-coupling scheme. The dependence of the 7 Li + 11 B optical potential on kinetic energy was taken into account. The deformation parameters of 7 Li and 11 B and optical model parameters for interaction of these nuclei in ground and excited states were deduced. The contributions of one-and two-step transfers to the elastic and inelastic scattering were estimated. A. A. RUDCHIK et al. PHYSICAL REVIEW C 72, 034608 (2005) 034608-2

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