Medical Radioisotopes Produced with Cyclotron Beams in Warsaw

The various production routes of the prospective medical radioisotopes 43Sc, 44gSc, 44mSc, 47Sc, 44Ti/44gSc, 99mTc, 72Se/72As and 211At were investigated by a team from the Heavy Ion Laboratory, University of Warsaw (HIL-UW), the University of Silesia (US) and the National Centre for Nuclear Research (NCNR). Three cyclotrons were employed: the K=160 heavy-ion cyclotron with an internal 32 MeV alpha particle beam and the p/d PETtrace medical cyclotron at HIL and the C30 proton cyclotron at NCNR in Świerk, near Warsaw. The Thick Target Yields, activity at the End of Bombardment (EOB) and the impurities produced in addition to the main isotope are reported. The possible medical applications of these radioisotopes are briefly discussed

Medical radioisotopes produced using the alpha particle beam from the Warsaw Heavy Ion Cyclotron

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 p A. This beam is used by the HIL-University of Silesia collaboration for the production of research quantities of 211At, 72Se/72As and 43;44Sc radioisotopes. The produced activities are transported to the Institute of Nuclear Chemistry and Technology inWarsaw where research on therapeutic and imaging radiopharmaceuticals based on these radioisotopes is pursued

Structure effects in Ne-20+Pb-208 quasi-elastic scattering

Preliminary results of an analysis of experiments devoted to a study of the sensitivity of the 20Ne + 208Pb quasi-elastic angular distributions at two near-barrier energies and the previously measured corresponding barrier distribution to the value of the nuclear quadrupole deformation length of 20Ne are reported

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

Precise calculation of parity nonconservation in cesium and test of the standard model

We have calculated the 6s-7s parity nonconserving (PNC) E1 transition amplitude, E_{PNC}, in cesium. We have used an improved all-order technique in the calculation of the correlations and have included all significant contributions to E_{PNC}. Our final value E_{PNC} = 0.904 (1 +/- 0.5 %) \times 10^{-11}iea_{B}(-Q_{W}/N) has half the uncertainty claimed in old calculations used for the interpretation of Cs PNC experiments. The resulting nuclear weak charge Q_{W} for Cs deviates by about 2 standard deviations from the value predicted by the standard model.Comment: 24 pages, 8 figure

Indirect Study of the 16O+16O Fusion Reaction Toward Stellar Energies by the Trojan Horse Method

The 16 O+ 16 O fusion reaction is important in terms of the explosive oxygen burning process during late evolution stage of massive stars as well as understanding of the mechanism of low-energy heavy-ion fusion reactions. We aim to determine the excitation function for the most major exit channels, α + 28 Si and p + 31 P, toward stellar energies indirectly by the Trojan Horse Method via the 16 O( 20 Ne , α 28 Si) α and 16 O( 20 Ne , p 31 P) α three-body reactions. We report preliminary results involving reaction identification, and determination of the momentum distribution of α - 16 O intercluster motion in the projectile 20 Ne nucleus

Isospin Asymmetry in Nuclei and Neutron Stars

The roles of isospin asymmetry in nuclei and neutron stars are investigated using a range of potential and field-theoretical models of nucleonic matter. The parameters of these models are fixed by fitting the properties of homogeneous bulk matter and closed-shell nuclei. We discuss and unravel the causes of correlations among the neutron skin thickness in heavy nuclei, the pressure of beta-equilibrated matter at a density of 0.1 fm$^{-3}$, the derivative of the nuclear symmetry energy at the same density and the radii of moderate mass neutron stars. Constraints on the symmetry properties of nuclear matter from the binding energies of nuclei are examined. The extent to which forthcoming neutron skin measurements will further delimit the symmetry properties is investigated. The impact of symmetry energy constraints for the mass and moment of inertia contained within neutron star crusts and the threshold density for the nucleon direct Urca process, all of which are potentially measurable, is explored. We also comment on the minimum neutron star radius, assuming that only nucleonic matter exists within the star.Comment: 49 pages, 17 figures, Phys. Rep. (in press); made improvements to "RAPR" and corrected transition densitie

Are the weak channels really weak?

The transfer probabilities for 20Ne + 90Zr and 20Ne + 92Zr at energies near the Coulomb barrier were measured. This quantity turned out to be very similar for both Zr isotopes and does not explain the observed differences in the barrier height distributions for these systems

Recent experimental results in sub- and near-barrier heavy ion fusion reactions

Recent advances obtained in the field of near and sub-barrier heavy-ion fusion reactions are reviewed. Emphasis is given to the results obtained in the last decade, and focus will be mainly on the experimental work performed concerning the influence of transfer channels on fusion cross sections and the hindrance phenomenon far below the barrier. Indeed, early data of sub-barrier fusion taught us that cross sections may strongly depend on the low-energy collective modes of the colliding nuclei, and, possibly, on couplings to transfer channels. The coupled-channels (CC) model has been quite successful in the interpretation of the experimental evidences. Fusion barrier distributions often yield the fingerprint of the relevant coupled channels. Recent results obtained by using radioactive beams are reported. At deep sub-barrier energies, the slope of the excitation function in a semi-logarithmic plot keeps increasing in many cases and standard CC calculations over-predict the cross sections. This was named a hindrance phenomenon, and its physical origin is still a matter of debate. Recent theoretical developments suggest that this effect, at least partially, may be a consequence of the Pauli exclusion principle. The hindrance may have far-reaching consequences in astrophysics where fusion of light systems determines stellar evolution during the carbon and oxygen burning stages, and yields important information for exotic reactions that take place in the inner crust of accreting neutron stars.Comment: 40 pages, 63 figures, review paper accepted for EPJ