SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Nyman Göran 1943 ) "

Sökning: WFRF:(Nyman Göran 1943 )

  • Resultat 61-70 av 122
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
61.
  • Cronqvist, M., et al. (författare)
  • Experimental-Determination of Cross-Talk between Neutron Detectors
  • 1992
  • Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - 0168-9002. ; 317:1-2, s. 273-280
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutron cross-talk measurements have been performed with 14.1 MeV neutrons for organic scintillator detectors with n-gamma discrimination capability. The probability for cross-talk between two 156 mm thick neutron detectors with a hexagonal cross section (effective diameter 167 mm) placed 0.33 m apart was found to be (2.5+/-1.1) 10(-4). A similar measurement between two 100 mm thick, cylindrically shaped detectors with 50 mm diameter and at 75 mm distance from each other yielded a cross-talk probability of (2.5+/-0.4) 10(-3). The measured cross-talk probabilities are in agreement with values from a Monte Carlo calculation.
  •  
62.
  • Diget, C. A., et al. (författare)
  • Breakup channels for C-12 triple-alpha continuum states
  • 2009
  • Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 80:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The triple-alpha-particle breakup of states in the triple-alpha continuum of C-12 has been investigated by way of coincident detection of all three alpha particles of the breakup. The states have been fed in the beta decay of N-12 and B-12, and the alpha particles measured using a setup that covers all of the triple-alpha phase space. Contributions from the breakup through the Be-8(0(+)) ground state as well as other channels-interpreted as breakup through excited energies in Be-8-have been identified. Spins and parities of C-12 triple-alpha continuum states are deduced from the measured phase-space distributions for breakup through Be-8 above the ground state by comparison to a fully symmetrized sequential R-matrix description of the breakup. At around 10 MeV in C-12, the breakup is found to be dominated by 0(+) strength breaking up through the ghost of the Be-8(0(+)) ground state with L = 0 angular momentum between the first emitted alpha particle and the intermediate Be-8 nucleus. For C-12 energies above the 12.7 MeV 1(+) state, however, L = 2 breakup of a C-12 2(+) state through the Be-8(2(+)) excited state dominates. Furthermore, the possibility of a 2(+) excited state in the 9-12 MeV region of C-12 is investigated.
  •  
63.
  • Diget, C. A., et al. (författare)
  • Properties of the C-12 10 MeV state determined through beta-decay
  • 2005
  • Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 760:1-2, s. 3-18
  • Tidskriftsartikel (refereegranskat)abstract
    • The beta-delayed triple-alpha particle decay of B-12 has been measured with a setup that favours coincidence detection. A broad state in C-12, previously reported around 10 MeV, has been seen and its properties determined through R-matrix analysis of the excitation spectrum. The spin and parity are 0(+). Interference between this state and the Hoyle state at 7.654 MeV has a marked influence on the spectrum. The coupling between the two states makes it difficult to determine the resonance energy. (c) 2005 Elsevier B.V. All rights reserved.
  •  
64.
  • Dragić, A.L., et al. (författare)
  • Shape-isomer studies with resonance neutron capture
  • 2014
  • Ingår i: Physics Procedia. - : Elsevier BV. - 1875-3884 .- 1875-3892. ; 59:C, s. 125-131
  • Konferensbidrag (refereegranskat)abstract
    • An experiment searching for formation of super-deformed shape isomers in odd uranium isotopes following neutron capture is designed at the GELINA neutron source of IRMM. We focus on neutron energies around the so-called intermediate structure in the fission cross-section, where the coupling between compound states above the first and the second minimum is largest. The experimental arrangement is described. The results of a feasibility study on the population of the shape isomer in 235U, using a 234U target, together with the results from first run with a 238U target are presented.
  •  
65.
  • Fynbo, H. O. U., et al. (författare)
  • Ar-31 examined: New limit on the beta-delayed three-proton branch
  • 1999
  • Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 59:4, s. 2275-2277
  • Tidskriftsartikel (refereegranskat)abstract
    • We have remeasured the decay of Ar-31 with a setup sensitive to multiparticle decay branches and obtained. a new limit of 1.1 x 10(-3) (99% C.L.) on the beta-delayed three-proton branch between the isobaric analog state in Cl-31 and the ground state of Si-28. This a factor of 17 below the previously reported first observation of beta-delayed three-proton emission in Ar-31. The limit on a possible beta 3p branch to the first excited state in Si-28 is 2.9 x 10(-4). [S0556-2813(99)04404-0].
  •  
66.
  • Fynbo, H. O. U., et al. (författare)
  • New information on the beta-decay of Li-11 from Doppler broadened gamma lines
  • 2004
  • Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 736:1-2, s. 39-54
  • Tidskriftsartikel (refereegranskat)abstract
    • The gamma-ray spectrum following beta-decay of Li-11 has been remeasured at the ISOLDE facility at CERN. Two new transitions were observed through the use of large Ge-detectors. Most gamma-decays will follow beta-delayed neutron emission. Information on the energy of the neutron is derived from analysis of the gamma line-shape and used to construct a partial decay scheme for Li-11. Lifetime values for the 1(-) and 2(-) levels in Be-10 are also derived. A new partial decay scheme is presented. (C) 2004 Elsevier B.V. All rights reserved.
  •  
67.
  • Fynbo, H. O. U., et al. (författare)
  • News on C-12 from beta-decay studies
  • 2004
  • Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 738, s. 59-65
  • Konferensbidrag (refereegranskat)abstract
    • We discuss the importance of the spectroscopic properties of the resonances of C-12 just above the 3alpha-threshold, and review the existing experimental information of this region with emphasis on 0(+) and 2(+) states. A new experimental approach for studying the beta-decays of B-12 and N-12 is presented based on techniques developed in the context of Radioactive beam (rare isotope) physics. Finally preliminary results from an ongoing analysis of two recent experiments are given.
  •  
68.
  • Fynbo, H. O. U., et al. (författare)
  • Revised rates for the stellar triple-alpha process from measurement of C-12 nuclear resonances
  • 2005
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687 .- 1476-4679. ; 433:7022, s. 136-139
  • Tidskriftsartikel (refereegranskat)abstract
    • In the centres of stars where the temperature is high enough, three alpha-particles (helium nuclei) are able to combine to form C-12 because of a resonant reaction leading to a nuclear excited state(1). (Stars with masses greater than similar to0.5 times that of the Sun will at some point in their lives have a central temperature high enough for this reaction to proceed.) Although the reaction rate is of critical significance for determining elemental abundances in the Universe(1), and for determining the size of the iron core of a star just before it goes supernova(2), it has hitherto been insufficiently determined(2). Here we report a measurement of the inverse process, where a C-12 nucleus decays to three alpha-particles. We find a dominant resonance at an energy of similar to11 MeV, but do not confirm the presence of a resonance at 9.1 MeV (ref. 3). We show that interference between two resonances has important effects on our measured spectrum. Using these data, we calculate the triple-a rate for temperatures from 10(7) K to 10(10) K and find significant deviations from the standard rates(3). Our rate below similar to5 x 10(7) K is higher than the previous standard, implying that the critical amounts of carbon that catalysed hydrogen burning in the first stars are produced twice as fast as previously believed(4). At temperatures above 10(9) K, our rate is much less, which modifies predicted nucleosynthesis in supernovae(5,6).
  •  
69.
  • Fynbo, H. O. U., et al. (författare)
  • The beta 2p decay mechanism of Ar-31
  • 2000
  • Ingår i: Nuclear Physics A. - 0375-9474. ; 677, s. 38-60
  • Tidskriftsartikel (refereegranskat)abstract
    • We have measured the beta-decay of Ar-31 with a high granularity setup sensitive to multiparticle decay branches. Two-proton emission is observed from the isobaric analog state in Cl-31 to the four lowest states in P-29 and furthermore from a large number of states fed in Gamow-Teller transitions. The mechanism of two-proton emission is studied via energy and angular correlations between the two protons. In all cases the mechanism is found to be sequential yielding information about states in S-30 up to 8 MeV excitation energy. Improved data on the beta-delayed one-proton branches together with the two-proton data provide precise information about the beta-strength distribution up to 15 MeV excitation energy.
  •  
70.
  • Fynbo, H. O. U., et al. (författare)
  • The β-decay approach for studying 12C
  • 2008
  • Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 111:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The β-decays of the mirror nuclei 12B and 12N both populate states in 12C and they are therefore a precious source of information about this nucleus. Due to the selection rules of β-decay only 0+, 1+ and 2+ states are populated. This allows a very clean study of unbound states just above the 3α-threshold with those spin and parities. This probe has been applied in two experiments using two complementary experimental techniques: in the first the three α-particles emitted after β-decay are measured in coincidence in separate detectors using the ISOL method, while in the second method 12B and 12N are implanted in a detector and the summed energy of the three α-particles is measured directly. Preliminary results from the two approaches are presented. © 2008 IOP Publishing Ltd.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 61-70 av 122
Typ av publikation
tidskriftsartikel (99)
konferensbidrag (22)
samlingsverk (redaktörskap) (1)
Typ av innehåll
refereegranskat (121)
övrigt vetenskapligt/konstnärligt (1)
Författare/redaktör
Nyman, Göran Hugo, 1 ... (120)
Jonson, Björn, 1941 (117)
Riisager, K. (102)
Nilsson, Thomas, 196 ... (94)
Borge, M. J. G. (94)
Fynbo, H. O. U. (60)
visa fler...
Tengblad, O (58)
Schrieder, G. (47)
Richter, A. (42)
Simon, H (41)
Tengblad, Olof, 1957 (40)
Emling, H. (34)
Geissel, H. (33)
Fraile, L. M. (33)
Kulessa, R. (29)
Chulkov, L. V. (29)
Aumann, T (28)
Jeppesen, H. B. (28)
Hansen, P. G. (27)
Zhukov, Mikhail, 194 ... (24)
Kratz, J. V. (22)
Meister, Mikael, 196 ... (22)
Aysto, J. (21)
Münzenberg, G. (21)
Madurga, M. (21)
Perea, A. (20)
Wilhelmsen, Katarina ... (20)
Johansson, Håkan T, ... (19)
Boretzky, K. (19)
Chatillon, A. (19)
Weick, H. (19)
Stroth, J. (18)
Mahata, K. (18)
Guillemaudmueller, D ... (18)
Alcorta, M. (17)
Mukha, I. (17)
Hornshoj, P. (17)
Cortina-Gil, D. (16)
Scheidenberger, C. (16)
Mueller, A. C. (16)
Reifarth, R (15)
Forssen, Christian, ... (15)
Paschalis, S. (15)
Summerer, K. (15)
Diget, C. A. (15)
Smedberg, Martin, 19 ... (15)
Rossi, D (14)
Turrion, M. (14)
Nickel, F. (14)
Wilhelmsen Rolander, ... (14)
visa färre...
Lärosäte
Chalmers tekniska högskola (121)
Lunds universitet (10)
Uppsala universitet (8)
Göteborgs universitet (4)
Språk
Engelska (121)
Svenska (1)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (122)
Teknik (3)
Medicin och hälsovetenskap (1)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy