| 1. |
- Bergenwall, Bel E., 1968-
(författare)
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From Particle-Production Cross Sections to KERMA and Absorbed Dose for the Case 96 MeV n-12C Interactions
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neutron-carbon interactions have been studied with a focus on charged-particle production of relevance to radiation protection and medical applications, such as cancer therapy. The measurements have been performed using the particle-detection setup, MEDLEY, and the 96 MeV neutron beam at the The Svedberg Laboratory in Uppsala.Double-differential cross sections of inclusive charged-particle production are compared with recent calculations from models based on the GNASH code including direct, preequilibrium and compound processes. For protons, the shapes of the cross-section spectra are reasonably well described by the calculations. For the other particles- d, t, 3He and α- there are important discrepancies, in particular for 3He-ions and α-particles, concerning both shape and magnitude of the spectra.Using the new cross sections, partial as well as total KERMA coefficients have been determined. The coefficients have also been compared to previous experimental results and model calculations. The p, d and t KERMA coefficients are in good agreement with those from a previous measurement. For the helium isotopes, there are no previous measurements at this energy. The KERMA coefficients are considerably higher (by up to 30%) than those predicted by the calculations.The KERMA results indicate that protons and α -particles are the main contributors to the dose. A 6x6x6 cm3 carbon phantom, exposed to a broad and a pencil-like beam, is used for the computation of the absorbed doses deposited by these two particles in spheres of 1 μm in diameter, located at various positions in the phantom. The maximum doses are deposited at ~3 cm from the surface of neutron impact for protons and within 1 cm for α-particles. For the pencil beam, deposited doses are spread over regions of ~1.5 cm and ~300 μm transverse to the beam for protons and α-particles, respectively. The results are consistent with previous integral measurements at lower energies.
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| 2. |
- Bergenwall, B., et al.
(författare)
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Experimental kerma coefficients for carbon deduced from microscopic cross sections at 96 MeV incident neutron energy
- 2004
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 49:19, s. 4523-4542
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Tidskriftsartikel (refereegranskat)abstract
- The double-differential cross sections for (n, px), (n, dx), (n, tx), (n, (3)Hex) and (n, alphax) reactions in carbon have been measured at 96 MeV incident neutron energy. The various charged particles (inclusive spectra) were identified using A E-E techniques. From the experimental data, energy- and angle-differential as well as production cross sections were determined, and subsequently the partial and total kerma coefficients. The deduced partial and total kerma coefficients were compared to previous experimental results and theoretical calculations. The findings indicate that the deduced kerma coefficients for the hydrogen isotopes are in good agreement with those deduced from a previous measurement, and that the kerma coefficient values, in particular of the hydrogen isotopes, are systematically higher than values obtained from recent model calculations, which consequently resulted in a total kerma coefficient which is up to 30% higher than predicted by the calculations.
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| 3. |
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| 4. |
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| 5. |
- Blideanu, V., et al.
(författare)
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Nucleon-induced reactions at intermediate energies : New data at 96 MeV and theoretical status
- 2004
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 70:1, s. 014607-
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Tidskriftsartikel (refereegranskat)abstract
- Double-differential cross sections for light charged particle production (up to A=4) were measured in 96 MeV neutron-induced reactions, at the TSL Laboratory Cyclotron in Uppsala (Sweden). Measurements for three targets, Fe, Pb, and U, were performed using two independent devices, SCANDAL and MEDLEY. The data were recorded with low-energy thresholds and for a wide angular range (20°–160°). The normalization procedure used to extract the cross sections is based on the np elastic scattering reaction that we measured and for which we present experimental results. A good control of the systematic uncertainties affecting the results is achieved. Calculations using the exciton model are reported. Two different theoretical approaches proposed to improve its predictive power regarding the complex particle emission are tested. The capabilities of each approach is illustrated by comparison with the 96 MeV data that we measured, and with other experimental results available in the literature.
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| 6. |
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| 7. |
- Lagergren, K, et al.
(författare)
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Coexistence of superdeformed shapes in Er-154
- 2001
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 8702:2
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Tidskriftsartikel (refereegranskat)abstract
- A new superdeformed rotational band has been observed in Er-154 using the Euroball Ge detector array. The new band and the one previously observed can be understood as based on coexisting superdeformed structures at prolate and triaxial shapes, respectively. The observation resolves long-standing difficulties in the theoretical interpretation of superdeformed states in Er-154.
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| 8. |
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| 9. |
- Sohler, D, et al.
(författare)
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Band-terminating states in Ag-101
- 2004
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Ingår i: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474 .- 1873-1554. ; 733:1-2, s. 37-52
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Tidskriftsartikel (refereegranskat)abstract
- Excited states of the neutron deficient Ag-101 nucleus have been investigated via the Cr-50(Ni-58, 3rho1alpha) heavy-ion induced reaction at 261 meV by use of in-beam spectroscopic methods. On the basis of the measured gammagamma-cincidence relations and angular distribution ratios high-spin bands have been extended up to I-pi = 35/2(+), 45/2((-)) and (49/2(-)). The negative parity states at the highest energy have been interpreted as terminating non-collective oblate states in the framework of the Nilsson-Strutinsky cranking formalism.
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| 10. |
- Tippawan, U., et al.
(författare)
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Light-ion production in the interaction of 96 MeV neutrons with silicon
- 2004
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 69:6
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Tidskriftsartikel (refereegranskat)abstract
- Double-differential cross sections for light-ion (p, d, t, He-3, and alpha) production in silicon, induced by 96 MeV neutrons, are reported. Energy spectra are measured at eight laboratory angles from 20degrees to 160degrees in steps of 20degrees. Procedures for data taking and data reduction are presented. Deduced energy-differential, angle-differential, and production cross sections are reported. Experimental cross sections are compared to theoretical reaction model calculations and experimental data in the literature.
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