| 1. |
- Ahrens, J., et al.
(författare)
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Measurement of the cosmic ray composition at the knee with the SPASE-2/AMANDA-B10 detectors
- 2004
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Ingår i: Astroparticle physics. - : Elsevier. - 0927-6505 .- 1873-2852. ; 21:6, s. 565-581
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Tidskriftsartikel (refereegranskat)abstract
- The mass composition of high-energy cosmic rays at energies above 1015 eV can provide crucial information for the understanding of their origin. Air showers were measured simultaneously with the SPASE-2 air shower array and the AMANDA-B10 Cherenkov telescope at the South Pole. This combination has the advantage to sample almost all high-energy shower muons and is thus a new approach to the determination of the cosmic ray composition. The change in the cosmic ray mass composition was measured versus existing data from direct measurements at low energies. Our data show an increase of the mean log atomic mass 〈lnA〉 by about 0.8 between 500 TeV and 5 PeV. This trend of an increasing mass through the "knee" region is robust against a variety of systematic effects. © 2004 Elsevier B.V. All rights reserved.
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| 2. |
- Andreyev, A. N., et al.
(författare)
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New microsecond isomers in Bi-189,Bi-190
- 2001
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 10:2, s. 129-133
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Tidskriftsartikel (refereegranskat)abstract
- New microsecond isomers in the neutron-deficient isotopes Bi-189g,Bi-190 have been identified after in-flight separation by the velocity filter SHIP. The evaporation residues were identified on the basis of delayed recoil-gamma /X-ray, recoil-gamma /X-ray-alpha and excitation function measurements. The systematics of the [pi 1i(13/2)]13/2(+) excited states in the odd-mass Bi nuclei is discussed.
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| 3. |
- Andreyev, A. N., et al.
(författare)
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The discovery of a prolate-oblate-spherical shape triple of spin 0(+) states in the atomic nucleus Pb-186
- 2001
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474 .- 1873-1554. ; 682, s. 482C-486C
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Tidskriftsartikel (refereegranskat)abstract
- Two excited J(pi)=0(+) states in Pb-186 populated in the a-decay of Po-190 have been identified through alpha -particle/conversion electron coincidences in an experiment at the velocity filter SHIP. The parent Po-190 nuclei have been produced in the Nd-142(Cr-52,4n)Po-190 complete fusion reaction, alpha -particle energies and branching ratios have been measured and hindrance factors were deduced. The observed states have been interpreted as the band heads of the known prolate and (yet unobserved) oblate rotational bands in Pb-186.
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| 4. |
- Van de Vel, K., et al.
(författare)
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Fine structure in the alpha decay of Po-188,Po-192
- 2003
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 68:5
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Tidskriftsartikel (refereegranskat)abstract
- The alpha decay of Po-188,Po-192 has been reexamined in order to probe the 0(+) states in the daughter nuclei Pb-184,Pb-188 that can be associated with coexisting spherical, oblate, and/or prolate configurations. Improved values were measured for the excitation energy and the feeding alpha -decay intensity of the 0(2)(+) state in Pb-184,Pb-188 and conflicting results on the 0(3)(+) state in Pb-188 were clarified. All known cases of fine structure in the alpha decay of the even-even Po nuclei are reviewed. The reduced alpha-decay width systematics combined with potential-energy-surface calculations confirm the onset of deformation in the ground state of the polonium nuclei around the neutron midshell. An isomeric state with a half-life of 580(100)ns has been identified in Po-192 .
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Andreyev, A. N., et al.
(författare)
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Shape-changing particle decays of Bi-185 and structure of the lightest odd-mass Bi isotopes
- 2004
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 69:5, s. 054308-
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Tidskriftsartikel (refereegranskat)abstract
- Proton and alpha decay of the proton-rich nuclide Bi-185 has been restudied in more detail in the complete fusion reaction Nb-93(Mo-95, 3n)Bi-185 at the velocity filter SHIP. The observed decay pattern of Bi-185 and of the heavier odd-mass isotopes Bi-187,Bi-189,Bi-191,Bi-193 are interpreted based on potential-energy surface calculations. It is shown that the experimental systematics of the particle decays and of the excited states in these nuclei (where known) can be explained by the prolate-oblate shape co-existence at low excitation energy. The observed state in Bi-185 is proposed to be of prolate nature, which is in contrast with the previously proposed oblate interpretation.
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| 9. |
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| 10. |
- Hazenkamp-Von Arx, M.E., et al.
(författare)
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PM2.5 and NO2 assessment in 21 European study centres of ECRHS II : annual means and seasonal differences
- 2004
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Ingår i: Atmospheric Environment. - : Elsevier. - 1352-2310 .- 1873-2844. ; 38:13, s. 1943-1953
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Tidskriftsartikel (refereegranskat)abstract
- The follow-up of cohorts of adults from more than 20 European centres of the former ECRHS I (1989-1992) investigates long-term effects of exposure to ambient air pollution on respiratory health, in particular asthma and change of pulmonary function. Since PM2.5 is not routinely monitored in Europe, we measured PM2.5 concentrations in 21 participating centres to estimate 'background' exposure in these cities. Winter (November-February), summer (May-August) and annual mean (all months) values of PM2.5 were determined from measuring periods between June 2000 and November 2001. Sampling was conducted for 7 days per month for a year. Annual and winter mean concentrations of PM2.5 vary substantially being lowest in Iceland and highest in centres in Northern Italy. Annual mean concentrations ranged from 3.7 to 44.9 mug m(-3), winter mean concentrations from 4.8 to 69.2 mug m(-3), and summer mean concentrations from 3.3 to 23.1 mugm(-3). Seasonal variability occurred but did not follow the same pattern across all centres. Therefore, ranking of centres varied from summer to winter. Simultaneously, NO2 concentrations were measured using passive sampling tubes. Annual mean NO2 concentrations range from 4.9 to 72.1 mug m(-3) with similar seasonal variations across centres and constant ranking of centres between seasons. The correlation between annual NO2 and PM2.5 concentrations is fair (Spearman correlation coefficient r(s) = 0.75), but when considered as monthly means the correlation is far less consistent and varies substantially between centres. The range of PM2.5 mass concentrations obtained in ECRHS II is larger than in other current cohort studies on long-term effects of air pollution. This substantial variation in PM2.5 exposure will improve statistical power in future multilevel health analyses and to some degree may compensate for the lack of information on within-city variability. Seasonal means may be used to indicate potential differences in the toxicity across the year. Across ECRHS cities annual NO2 might serve as a surrogate for PM2.5, especially for past exposure assessment, when PM2.5 is not available.
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