| 1. |
- Atac Nyberg, Ayse, et al.
(författare)
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Discrimination of gamma rays due to inelastic neutron scattering in AGATA
- 2009
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 607:3, s. 554-563
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Tidskriftsartikel (refereegranskat)abstract
- Possibilities of discriminating neutrons and gamma rays in the AGATA gamma-ray tracking spectrometer have been investigated with the aim of reducing the background due to inelastic scattering of neutrons in the high-purity germanium crystals. This background may become a serious problem especially in experiments with neutron-rich radioactive ion beams. Simulations using the GEANT4 toolkit and a tracking program based on the forward tracking algorithm were carried out by emitting neutrons and gamma rays from the center of AGATA. Three different methods were developed and tested in order to find "fingerprints" of the neutron interaction points in the detectors. In a simulation with simultaneous emission of six neutrons with energies in the range 1-5 MeV and 10 gamma rays with energies between 150 and 1450 keV, the peak-to-background ratio at a gamma-ray energy of 1.0 MeV was improved by a factor of 2.4 after neutron rejection with a reduction of the photopeak efficiency at 1.0 MeV of only a factor of 1.25. (C) 2009 Elsevier B.V. All rights reserved.
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| 2. |
- Bergenwall, B., et al.
(författare)
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Neutron-induced light charged particle production in carbon at 96 MeV
- 2005
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474 .- 1873-1554. ; 747:2-4, s. 152-181
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Tidskriftsartikel (refereegranskat)abstract
- Differential cross sections of charged particle production, i.e., p, d, t, 3He-ions and α-particles, in 96 MeV neutron-carbon interactions have been measured at laboratory angles in the range 20° to 160° in steps of 20°. The experimental techniques are described as well as the procedures for acquisition, analysis, reduction and correction of the data. Results including double differential, energy-differential, angle-differential and total particle production cross sections are reported and constitute the first data set with five ejectiles at such a high neutron energy. Thanks to the low-energy thresholds, 50% of the production cross section of α-particles, and 85% of the production cross sections of protons and deuterons, could be measured. For α-particles, the measured fraction is much higher than what has been achieved earlier at lower energies. The results on the hydrogen isotopes agree fairly well with a previous measurement at 95 MeV and with recent GNASH calculations. For the helium isotopes, however, there are important discrepancies in spectral shape and magnitude between the new results and the model calculations.
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| 3. |
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| 4. |
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| 5. |
- Tippawan, U., et al.
(författare)
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Light-ion production in the interaction of 96 MeV neutrons with oxygen
- 2006
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 73:3
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Tidskriftsartikel (refereegranskat)abstract
- Double-differential cross sections are reported for light-ion (p, d, t, (3)He, and alpha) production in oxygen induced by 96 MeV neutrons. Energy spectra are measured at eight laboratory angles from 20 degrees to 160 degrees in steps of 20 degrees. Procedures for data taking and data reduction are presented. Deduced energy-differential and production cross sections are reported. Experimental cross sections are compared to theoretical reaction model calculations and experimental data at lower neutron energies in the literature. The measured proton data agree reasonably well with the results of the model calculations, whereas the agreement for the other particles is less convincing. The measured production cross sections for protons, deuterons, tritons, and alpha particles support the trends suggested by data at lower energies.
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| 6. |
- Wadsworth, R., et al.
(författare)
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THE NORTHWEST FRONTIER : SPECTROSCOPY OF N similar to Z NUCLEI BELOW MASS 100
- 2009
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Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 40:3, s. 611-620
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Tidskriftsartikel (refereegranskat)abstract
- The spectroscopy and structure of excited states of N similar to Z nuclei in the mass 70-100 region has been investigated using two techniques. In the A similar to 70-80 region fusion evaporation reactions coupled with the recoil-beta-tagging method have been employed at Jyvaskyla to study low-lying states in odd-odd N = Z nuclei. Results from these and other data for known odd-odd nuclei above mass 60 will be discussed. In the heavier mass 90 region a fragmentation experiment has been performed using the RIS-ING/FRS setup at GSI. This experiment was primarily aimed at searching for spin gap isomers in nuclei around A similar to 96. The objectives of the latter experiment will be discussed.
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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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