On the depth dependence of spallation reactions in a spherical thick diorite target homogeneously irradiated by 600 MeV protons

Michel, R.; Dragovitsch, P.; Englert, P.; Peiffer, F.; Stück, R.; Theis, Sabine; Begemann, F.; Weber, H. W.; Signer, P.; Wieler, R.; Filges, D.; Cloth, P.

doi:10.1016/0168-583x(86)90228-4

Cited by 49 publications

(21 citation statements)

References 30 publications

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“…, 1989b, 1991a,b, 1993aMichel and Zanda, 1992;Dragovitsch et a/., 1990;Herpers et a/., 1991;13handari et al, 1993). They were of a priori type based on the experience of the previous 600 MeV simulation experiments (Michel et a/ ., 1985a. 1989aDittrich et a/., 1989;Gilabert et al, 1992Gilabert et al, , 1993).…”

Section: Discussion History Of Model Calculationsmentioning

confidence: 99%

“…The production rates of these nuclides were determined by accelerator mass spectrometry (AMS). We propose a method for the improvement of excitation functions on the basis of the experiences from these thick-target experiments and demonstrate these improvements by reproducing the experimental production rates measured in the two artificial meteoroids irradiated with 1.6 GeV protons as well of those obtained earlier for artificial stony meteoroids irradiated at CERN with 600 MeV protons (Michel et al, 1985a(Michel et al, , 1989a. Results for stable rare gas isotopes and for radionuclides from heavier and complex target elements will be presented separately in due course.…”

Section: Introductionmentioning

confidence: 99%

“…This conclusion is no longer true. The reason for the formerly good agreement between calculation and experiment as in case of the production of %o from Fe (Michel et al, 1985a(Michel et al, , 1989a(Michel et al, , 1993b, which cannot be produced by neutroninduced reactions, was just a lucky misinterpretation. The agreement was simply caused by the fact that the proton cross sections used were already compromised by secondary particles (Michel et al, 1995b).…”

Section: Modeling Production Rates By a Priori Calculationsmentioning

confidence: 99%

“…The model must be independent of special experimental setup. In addition to the irradiations discussed here, our collaboration have performed since 1985 three other simulation experiments with artificial stone meteoroids with radii of 5, 15, and 25 cm (Michel et al, 1985a;Aylmer et al, 1987;Dragovitsch, 1987;Michel et aL, 1989a;Theis et al, 1984Theis et al, , 1986. The spheres made of diorite (5 cm) or gabbro (1 5 and 25 cm) were irradiated isotropically with 600 MeV protons at the CERN synchrocyclotron.…”

Section: Model Calculations Nuclide Production In Mixed Particle Fieldsmentioning

confidence: 99%

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Simulation of the interaction of galactic cosmic‐ray protons with meteoroids: On the production of radionuclides in thick gabbro and iron targets irradiated isotropically with 1.6 GeV protons

Leya

Lange

Lüpke

et al. 2000

Meteorit & Planetary Scien

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— Thick spherical targets made of gabbro (R = 25 cm) and of steel (R = 10 cm) were irradiated isotropically with 1.6 GeV protons at the Saturne synchrotron at Laboratoire National Saturne (LNS)/CEN Saclay in order to simulate the interaction in space of galactic cosmic‐ray (GCR) protons with stony and iron meteoroids. Proton fluences of 1.32 × 1014 cm−2 and 2.45 × 1014 cm−2 were received by the gabbro and iron sphere, respectively, which corresponds to cosmic‐ray exposure ages of about 1.6 and 3.0 Ma. Both artificial meteoroids contained large numbers of high‐purity target foils of up to 28 elements at different depths. In these individual target foils, elementary production rates of radionuclides and rare gas isotopes were measured by x‐ and γ‐spectrometry, by low‐level counting, accelerator mass spectrometry (AMS), and by conventional rare gas mass spectrometry. Also samples of the gabbro itself were analyzed. Up to now, for each of the experiments, ∼500 target‐product combinations were investigated of which the results for radionuclides are presented here. The experimental production rates show a wide range of depth profiles reflecting the differences between low‐, medium‐, and high‐energy products. The influence of the stony and iron matrices on the production of secondary particles and on particle transport, in general, and consequently on the production rates is clearly exhibited by the phenomenology of the production rates as well as by a detailed theoretical analysis. Theoretical production rates were calculated in an a priori way by folding depth‐dependent spectra of primary and secondary protons and secondary neutrons calculated by Monte Carlo techniques with the excitation functions of the underlying nuclear reactions. Discrepancies of up to a factor of 2 between the experimental and a priori calculated depth profiles are attributed to the poor quality of the mostly theoretical neutron excitation functions. Improved neutron excitation functions were obtained by least‐squares deconvolution techniques from experimental thick‐target production rates of up to five thick‐target experiments in which isotropic irradiations were performed. A posteriori calculations using the adjusted neutron cross sections describe the measured depth profiles of all these simulation experiments within 9%. The thus validated model calculations provide a basis for reliable physical model calculations of the production rates of cosmogenic nuclides in stony and iron meteorites as well as in lunar samples and terrestrial materials.

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Section: Discussion History Of Model Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Modeling Production Rates By a Priori Calculationsmentioning

confidence: 99%

Section: Model Calculations Nuclide Production In Mixed Particle Fieldsmentioning

confidence: 99%

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Simulation of the interaction of galactic cosmic‐ray protons with meteoroids: On the production of radionuclides in thick gabbro and iron targets irradiated isotropically with 1.6 GeV protons

Leya

Lange

Lüpke

et al. 2000

Meteorit & Planetary Scien

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“…The exposure ages of the two samples are thus found to be 7.4 and 6.2 Ma, respectively. The latter value at larger shielding depth is probably more reliable, because the contribution oflow-energy solar flare particles has not been taken into account, and their contribution was significant at the smaller depth (Michel et al, 1986). The [22Nef2'Ne] ratios of 1.25 and 1.22 obtained after blank and mass discrimination correction are higher than values usually found in chondrites.…”

Section: Resultsmentioning

confidence: 48%

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1988

Meteoritics

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Abstract-Cosmic ray produced tracks, He and Ne isotopes and radionuclides have been studied in the recently fallen H5 chondrite Gujargaon. The results indicate an exposure age of about 7 Ma. The high track production rates of 0.25 to 0.69 x 10 6 cm? Ma-' suggest that the Gujargaon meteoroid had a small size (RE = 9-10 ern) in space and suffered 1-3 em ablation in the atmosphere. The conclusion about the meteoroid size is supported by the low activity of neutron capture isotope 60CO and high spallogenic 22NePINe ratio of about 1.25. The data on long lived isotopes lOBe, S3Mn and 26AI are used to derive production rates of these isotopes in a rock having a radius of 9 em and the activity levels of the short lived isotopes 22Na and 54Mn are used to estimate the effect of modulation of galactic cosmic rays at the time of solar maximum of 1982.

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Simulation of the interactions of galactic cosmic ray protons by irradiation of a thick stony target with 1.6 GeV protons

Michel¹,

Lüpke²,

Herpers

et al. 1993

Journal of Radioanalytical and Nuclear Chemistry, Articles

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On the depth dependence of spallation reactions in a spherical thick diorite target homogeneously irradiated by 600 MeV protons

Cited by 49 publications

References 30 publications

Simulation of the interaction of galactic cosmic‐ray protons with meteoroids: On the production of radionuclides in thick gabbro and iron targets irradiated isotropically with 1.6 GeV protons

Simulation of the interaction of galactic cosmic‐ray protons with meteoroids: On the production of radionuclides in thick gabbro and iron targets irradiated isotropically with 1.6 GeV protons

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Simulation of the interactions of galactic cosmic ray protons by irradiation of a thick stony target with 1.6 GeV protons

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