A. Stolarz

Signature of a neutron halo in 232Th from antiproton absorption

Abstract We demonstrate a new method for the investigation of the neutron to proton density ratio at the nuclear surface. The method relies on the radiochemical determination of some residual nuclei after the annihilation of stopped antiprotons. A clear neutron halo effect has been observed with the 232 Th target.

Production of medical Sc radioisotopes with an alpha particle 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 42Ca 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 emitters 43Sc, 44gSc and 44mSc. The different paths for the production of the long lived 44mSc/44gSc 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 44mSc/44gSc 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 CaCO3 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 powder targets of hard materials for neutron halo studies

Abstract The powder sedimentation from a glue solution has been used for preparation of the thick targets of high melting point elements. This technique is particularly suitable for expensive enriched isotopic materials available in very limited amount. The targets of 96 Ru, 104 Ru, 130 Te, 183 W, 192 Os (with thickness range of 25–65 mg/cm 2 ) were prepared by this method. The target thickness uniformity was examined by X-ray absorption and variations less than 10% were found.

Target preparation for research with charged projectiles

The paper reviews in a compact format the techniques most frequently used for target preparation, such as rolling, powder compacting, and vacuum deposition. The survey covers also the techniques used for target characterisation (thickness, purity) and problems related to the extension of target life-time and time of uninterrupted experiments with use of targets.

Antiprotonic investigation of the nuclear periphery

Some results inferred from a program devoted to the study of the nuclear periphery using antiprotonic atoms are presented.

211At labeled substance P (5–11) as potential radiopharmaceutical for glioma treatment

INTRODUCTION The purposes of the present work were to label substance P (5-11) with 211At using a rhodium(III) complex with a bifunctional ligand-2-(1,5,9,13-tetrathiacyclohexadecan-3-yloxy)acetic acid ([16aneS4]-COOH) and to assess the in vitro stability and toxicity of the obtained radiobioconjugate. METHODS Two approaches were evaluated to obtain 131I/211At-Rh[16aneS4]-SP5-11 radiobioconjugates, based on 2-step and 1-step syntheses. In the first method 131I/211At-Rh[16aneS4]-COOH complexes were obtained that required further coupling to a biomolecule. In the second approach, the bioconjugate [16aneS4]-SP5-11 was synthesized and further labeled with 131I and 211At through the utilization of a Rh(III) metal cation bridge. The synthesized compounds were analyzed by HPLC, TLC and paper electrophoresis. RESULTS The 131I/211At-Rh[16aneS4]-COOH complexes were obtained in high yield and possessed good stability in PBS and CSF. Preliminary studies on coupling of 131I-Rh[16aneS4]-COOH to substance P (5-11) in 2-step synthesis showed that this procedure was too long with respect to 211At half-life, prompting us to improve it by finally using a 1-step synthesis. This strategy not only shortened the labeling time, but also increased final yield of 131I/211At-Rh[16aneS4]-SP5-11 radiobioconjugates. The stability of both compounds in PBS and CSF was high. Toxicity studies with the 211At-Rh[16aneS4]-SP5-11 demonstrated that radiobioconjugate significantly reduced T98G cell viability in a dose dependent manner reaching 20% of survival at the highest radioactivity 1200kBq/mL. CONCLUSIONS The radiobioconjugate 211At-Rh[16aneS4]-SP5-11 revealed its potential in killing glioma T98G cells during in vitro studies; therefore further animal studies to are required to determine its in vivo stability and treatment potential in normal and xenografted mice.

Gold fragmentation induced by stopped antiprotons

A natural gold target was irradiated with the antiproton beam from the low-energy antiproton ring at CERN. Antiprotons of

Kinetics of tritium isotope exchange between liquid pyrrole and gaseous hydrogen

200\mathrm{MeV}/c

Antiproton-nucleus annihilation at rest

momentum were stopped in a thick target, products of their annihilations on Au nuclei were detected using the off-line

Lifetime measurements in Nd138

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