Interactions of relativistic heavy ions in thick heavy element targets and some unresolved problems

Brandt, R.; Ditlov, V.A.; Dwivedi, K.K.; Ensinger, Wolfgang; Ganssauge, E.; Guo, Shi-Lun; Hashemi-Nezhad, S.R.; Khan, H.A.; Krivopustov, M.I.; Odoj, R.; Pozharova, E. A.; Smirnitzki, V. A.; Westmeier, W.; Zamani-Valasiadou, M.

doi:10.1134/s1063779608020044

Cited by 9 publications

(31 citation statements)

References 24 publications

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“…The results reported in [1,2] show evidence that secondary fragments excite target nuclei stronger than primary ions, thus producing more neutrons than expected from calculation. Findings from [1][2][3] are not in contradiction as will be shown [4]. It seems that as if unresolved problems arise only after an energetic limit that is barely approached in the 1 GeV/u 238 U + Fe experiment.…”

Section: Ionmentioning

confidence: 75%

“…All neutrons induce (n, γ) and other reactions in various sensors. Details are given in [1,2,[7][8][9][10], only a short description will be given here. Using the lanthanum sensor, which is monoisotopic stable 139 La, one can study the neutron capture reaction 139 La n, γ 140 La −→ β-decay, T 1/2 = 40.28 hours .…”

Section: Neutron Emission From the "Gamma-2" Target Irradiated With Pmentioning

confidence: 99%

“…Recent investigations on the interaction of relativistic ions (called primaries in this paper) above a total energy E kin > 10 GeV in thick heavy-element targets show unexpected phenomena in the spallation yield distributions, as well as surprisingly intense neutron emission. These unexpected phenomena constitute "unresolved problems" as described in [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…(1) Spallation mass-yield curves in any thin target are completely understood with conventional reaction models like "limiting fragmentation" and "factorisation" [1,2]. However, the spallation mass-yield curves in thick targets which are also produced by secondary fragments, generated in the interaction of primaries with target nuclei, are incompatible with these concepts of "limiting fragmentation" and "factorisation."…”

Section: Introductionmentioning

confidence: 99%

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Neutron Production in Thick Targets Irradiated with High-Energy Ions

Hashemi-Nezhad

Zamani-Valasiadou

Krivopustov

et al. 2011

Physics Research International

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The neutron production in thick targets irradiated with 1 GeV protons was studied experimentally, and results are well understood with model calculations, including MCNPX 2.7a. However, one observes very large neutron production rates in the interaction of 44 GeV 12C onto thick Cu-, Pb-, and U-targets beyond calculated rates. The experimental spallation product yield curve in a 20 cm thick Cu target irradiated with 72 GeV 40Ar also cannot be reproduced by several model codes, including MCNPX 2.7a. This may be due to secondary fragments produced in high energy ( GeV) heavy-ion interactions which destroy target nuclei more effectively than primary ions. These observed experimental facts constitute “unresolved problems” from a fundamental point of view. It may have an impact on radiation protection issues for future heavy-ion accelerators.

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Section: Ionmentioning

confidence: 75%

Section: Neutron Emission From the "Gamma-2" Target Irradiated With Pmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Neutron Production in Thick Targets Irradiated with High-Energy Ions

Hashemi-Nezhad

Zamani-Valasiadou

Krivopustov

et al. 2011

Physics Research International

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“…This paper presents additional information which shall help to come closer to the understanding of "unresolved problems" in heavy ion interactions in thick targets [16] above an energetic threshold of E CM /u ≈ 150 MeV [2] and to understand BURSTS [1] in the same context.…”

Section: Discussionmentioning

confidence: 99%

Further Studies of BURSTS and Spallation in High-Energy Heavy Ion Reactions

Hashemi-Nezhad¹,

Brandt²,

Ditlov³

et al. 2017

WJNST

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Aspects of BURSTS and Spallation reactions induced by high-energy heavy ions in thick targets (>10 cm thick) will be investigated: BURSTS are reviewed from a historical and phenomenological point-of-view. Details of interactions in nuclear emulsions will be compared for irradiations of 72 GeV 22 Ne-ions from Dubna with irradiations of 72 GeV 40 Ar-ions from Berkeley. Measured correlations in individual interactions between multiplicities of "minimum ionizing particles", n s , and "black prongs", n b , will be shown as "n s -vs.-n b " per event for BURSTS and separately for Spallation in interactions of 72 GeV 22 Ne-ions. Monte Carlo calculations, based on the MCNPX 2.7 code, have been carried out for 72 GeV 22 Ne interacting in nuclear emulsions: The correlation between n s and n b in Spallation reactions could be understood. However, "n s -vs.-n b " correlations from BURST-interactions could not be reproduced with this model for events with small numbers of heavy prongs n h ≤ 10. For large numbers of heavy prongs with n h > 10 one could find some agreement between experiments and calculations, however, not in all details. Further experimental and theoretical studies are necessary before one has a complete understanding of BURST interactions in high-energy heavy ion reactions.

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