| 1. |
- Andersson, Pernilla, et al.
(författare)
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An upgrade of the SCANDAL facility for neutron scattering measurements at 175 MeV
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The experimental setup SCANDAL (SCAttered Nucleon Detection AssembLy) at the The Svedberg Laboratory (TSL), previously used for measurements of the differential cross section of elastic and inelastic neutron scattering in the 50 – 130 MeV range, has recently been upgraded with new Na doped CsI scintillating detectors for measurements at 175 MeV. The performance of the new setup is described and illustrated by the early steps in the analysis of the first experimental campaign, carried out in January and February 2009.
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| 2. |
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| 3. |
- Mermod, Philippe, et al.
(författare)
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95 MeV neutron scattering on hydrogen, deuterium, carbon and oxygen
- 2006
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:5, s. 054002-
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Tidskriftsartikel (refereegranskat)abstract
- Three neutron-deuteron scattering experiments at 95 MeV have been performed recently at The Svedberg Laboratory in Uppsala. Subsets of the results of these experiments have been reported in two short articles, showing clear evidence for three-nucleon force effects. In this paper, we present a more detailed description of the experimental methods as well as further discussion of the results. In addition to neutron-deuteron scattering data, neutron-proton and C12(n,n) elastic scattering data have been measured for normalization purposes, and O16(n,n) data have been obtained for the first time at this energy. It was possible to extract C12(n,n') and O16(n,n') inelastic scattering cross sections to excited states below 12 MeV excitation energy. The inelastic scattering data (for both carbon and oxygen) are shown to have a significant impact on the determination of nuclear recoil kerma coefficients.
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| 4. |
- Pomp, Stephan, et al.
(författare)
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An iterative procedure to obtain inverse response functions for thick-target correction of measured charged-particle spectra
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 572:2, s. 893-898
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Tidskriftsartikel (refereegranskat)abstract
- A new method for correcting charged-particle spectra for thick-target effects is described. Starting with a trial function, inverse response functions are found by an iterative procedure. The variances corresponding to the measured spectrum are treated similarly and in parallel. Oscillations of the Solution are avoided by rebinning the data to finer bins during a correction iteration and back to the original or wider binning after each iteration. This thick-target correction method has been used for data obtained with the MEDLEY facility at the The Svedberg Laboratory, Uppsala, Sweden, and is here presented in detail and demonstrated for two test cases.
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| 5. |
- Sarsour, M., et al.
(författare)
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Measurement of the Absolute Differential Cross Section for np Elastic Scattering at 194 MeV
- 2006
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:4, s. 044003-
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Tidskriftsartikel (refereegranskat)abstract
- A tagged medium-energy neutron beam was used in a precise measurement of the absolute differential cross section for np backscattering. The results resolve significant discrepancies within the np database concerning the angular dependence in this regime. The experiment has determined the absolute normalization with +/- 1.5% uncertainty, suitable to verify constraints of supposedly comparable precision that arise from the rest of the database in partial wave analyses. The analysis procedures, especially those associated with the evaluation of systematic errors in the experiment, are described in detail so that systematic uncertainties may be included in a reasonable way in subsequent partial wave analysis fits incorporating the present results.
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| 6. |
- Tippawan, Udomrat, et al.
(författare)
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Light charged-particle production in 96 MeV neutron-induced reactions on carbon and oxygen
- 2007
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 126:1-4, s. 35-39
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, an increasing number of applications involving fast neutrons have been developed or are under consideration, e.g. radiation treatment of cancer, neutron dosimetry at commercial aircraft altitudes, soft-error effects in computer memories, accelerator-driven transmutation of nuclear waste and energy production and determination of the response of neutron detectors. Data on light-ion production in tight nuclei such as carbon, nitrogen and oxygen are particularly important in calculations of dose distributions in human tissue for radiation therapy at neutron beams, and for dosimetry of high-energy neutrons produced by high-energy cosmic radiation interacting with nuclei (nitrogen and oxygen) in the atmosphere. When studying neutron dose effects, it is especially important to consider carbon and oxygen, since they are, by weight, the most abundant elements in human tissue. Preliminary experimental double-differential cross sections of inclusive light-ion (p, d, t, He-3 and alpha) production in carbon induced by 96-MeV neutrons have been presented. Energy spectra were measured at eight laboratory angles: 20, 40, 60, 80, 100, 120, 140 and 160 degrees. Measurements were performed at The Svedberg Laboratory (TSL), Uppsala, using the dedicated MEDLEY experimental setup. The authors have earlier reported experimental double-differential cross sections of inclusive light-ion production in oxygen. In this paper, the deduced kerma coefficients for oxygen has been presented and compared with reaction model calculations.
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| 7. |
- Öhrn, Angelica, et al.
(författare)
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Elastic scattering of 96 MeV neutrons from iron, yttrium, and lead
- 2008
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 77:2, s. 024605-
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Tidskriftsartikel (refereegranskat)abstract
- Data on elastic scattering of 96 MeV neutrons from Fe-56, Y-89, and Pb-208 in the angular interval 10-70 degrees are reported. The previously published data on Pb-208 have been extended, as a new method has been developed to obtain more information from data, namely to increase the number of angular bins at the most forward angles. A study of the deviation of the zero-degree cross section from Wick's limit has been performed. It was shown that the data on Pb-208 are in agreement with Wick's limit while those on the lighter nuclei overshoot the limit significantly. The results are compared with modern optical model predictions, based on phenomenology and microscopic nuclear theory. The data on Fe-56, Y-89, and Pb-208 are in general in good agreement with the model predictions.
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| 8. |
- Österlund, Michael, et al.
(författare)
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Elastic neutron scattering studies at 96 MeV for transmutation
- 2007
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 126:1-4, s. 119-122
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Tidskriftsartikel (refereegranskat)abstract
- Elastic neutron scattering from (12)c, N-14, O-16, Si-28, (40) Ca, Fe-56, Y-89 and Ph-208 has been studiedl at 96 MeV in the10-70 degrees interval, using the SCANDAL (SCAttered Nucleon Detection AssembLy) facility. The results for C-12 and Pb-208 have recently been published, while the data on the other nuclei are under analysis. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. A novel method for normalisation of the absolute scale of the cross section has been used. The estimated normalisation uncertainty, 3%, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. Elastic neutron scattering is of utmost importance for a vast number of applications. Besides its fundamental importance as a laboratory for tests of isospin dependence in the nucleon-nucleon, and nucleon-nucleus, interaction, knowledge of the optical potentials derived from elastic scattering come into play in virtually every application where a detailed understanding of nuclear processes is important. Applications for these measurements are dose effects due to fast neutrons, including fast neutron therapy, as well as nuclear waste incineration and single event upsets in electronics. The results at light nuclei of medical relevance (C-12, N-14 and O-16) are presented separately. In the present contribution, results on the heavier nuclei are presented, among which several are of relevance to shielding of fast neutrons.
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