No abstract available

No abstract available

No abstract available

[en] The de-excitation of levels in ^119-125Sn populated in the decay of In isotopes has been studied using on-line isotope separators. Level half-lives have been measured in ^119-123Sn. A near cancellation of the matrix element for B(E2; gsub(7/2) → dsub(3/2)) is observed to occur in ¹²¹Sn and is probably due to pairing effects. Very low lying 9/2^- levels have been observed in ^122-125Sn and are suggested in ¹²⁷,¹²⁹Sn. These levels have been interpreted as three quasi-particle states based on the unique parity hsub(11/2) level. A possible mixing of the gsub(7/2) level with a close lying 7/2⁺ three quasi-particle state in ¹²¹Sn is discussed. (orig.)

[en] The de-excitation of levels in ^119-125Sn populated in the decay of In isotopes has been studied using on-line isotope separators. Level half-lives have been measured in ^119-123Sn. A near cancellation of the matrix element for B(E2;gsub(7/2)→Dsub(3/2)) is observed to occur in ¹²¹Sn and is probably due to pairing effects. Very low lying 9/2^- levels have been observed in ^121-125Sn and are suggested in ¹²⁷¹²⁹Sn. These levels have been interpreted as three quasi-particle states based on the unique parity Hsub(11/2) level. A possible mixing of the Gsub(7/2) level with a close lying 7/2⁺ three quasi particle state in ¹²³Sn is discussed. (Auth.)

[en] The electron cooler at CRYRING is now operating with a superconducting gun solenoid and an electron beam that is adiabatically expanded with a factor of up to 100. This paper describes the new gun solenoid and electron gun. It presents measurements made on longitudinal cooling forces with different expansion factors, electron densities, magnetic field strengths and beam alignments. It also presents studies of a transverse beam instability that appears when a misalignment is introduced between ion and electron beams. Finally, some measurements of dielectronic recombination that directly yield transverse and longitudinal electron temperatures are discussed

[en] The heavy-ion storage ring CRYRING at the Manne Siegbahn Laboratory at Stockholm University has been used for the study of dissociative recombination of ³HeH⁺. The new adiabatically expanded electron beam at CRYRING, which is achieved by means of a superconducting magnet, was used. The electron-beam expansion factor of 100 gave a transverse electron temperature of about 1 meV. This allowed the observation of several new resonances in the recombination cross-section

[en] Branching ratios in dissociative recombination of C₂H₂⁺ molecular ions with electrons were measured using the CRYRING heavy-ion storage ring. We have determined complete branching ratios for C₂H₂⁺ at collision energies between 0 and 7.4 MeV. We found dissociative recombination of C₂H₂⁺ to be dominated by the two-body C₂H+H and three-body C₂+H+H channels, with branching ratios of 0.50±0.06 and 0.30±0.05, respectively. The branching to CH+CH was measured to be 0.13±0.01, whereas two other energetically allowed channels were found to be almost negligible. (author)

[en] Recently we described a photosynthetic method for preparation of ₁₁C-labelled glucose using green algae. We have now developed the method further and included new techniques for purification and analysis of the obtained material. In the thin layer chromatographic analysis of the carbohydrates produced by the algae only one radioactive component was revealed. The systems used could not clearly separate glucose, fructose and mannose. The glucose content was determined using a specific method based on glucose oxidase whereas fructose was determined by an unspecific chemical procedure. The data thus obtained indicated that the algae produced glucose and fructose in a ratio of about 2:1. Mannose was not known to be present in the green algae used. GLC and HPLC have now other radioactive components to be present in the product. The ₁₁C-glucose produced by the algae and purified by HPLC has been used in positron emission tomography studies

[en] Dissociative recombination (DR) of water cluster ions H⁺(H₂O)_n (n=4-6) with free electrons has been studied at the heavy-ion storage ring CRYRING (Manne Siegbahn Laboratory, Stockholm University). For the first time, branching ratios have been determined for the dominating product channels and absolute DR cross sections have been measured in the energy range from 0.001 to 0.7 eV. Dissociative recombination is concluded to result in extensive fragmentation for all three cluster ions, and a maximum number of heavy oxygen-containing fragments is produced with a probability close to unity. The branching ratio results agree with earlier DR studies of smaller water cluster ions where the channel nH₂O+H has been observed to dominate and where energy transfer to internal degrees of freedom has been concluded to be highly efficient. The absolute DR cross sections for H⁺(H₂O)_n (n=4-6) decrease monotonically with increasing energy with an energy dependence close to E^-1 in the lower part of the energy range and a faster falloff at higher energies, in agreement with the behavior of other studied heavy ions. The cross section data have been used to calculate DR rate coefficients in the temperature range of 10-2000 K. The results from storage ring experiments with water cluster ions are concluded to partly confirm the earlier results from afterglow experiments. The DR rate coefficients for H⁺(H₂O)_n (n=1-6) are in general somewhat lower than reported from afterglow experiments. The rate coefficient tends to increase with increasing cluster size, but not in the monotonic way that has been reported from afterglow experiments. The needs for further experimental studies and for theoretical models that can be used to predict the DR rate of polyatomic ions are discussed