Observations of the Li, Be, and B isotopes and constraints on cosmic-ray propagation

Nolfo, G. A. de; Moskalenko, I. V.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Davis, A. J.; George, Jimin; Hink, P. L.; Israel, M. H.; Leske, R. A.; Lijowski, M.; Mewaldt, R. A.; Stone, E. C.; Strong, A. W.; Rosenvinge, T. T. von; Wiedenbeck, M. E.; Yanasak, N. E.

doi:10.1016/j.asr.2006.09.008

Cited by 59 publications

(56 citation statements)

References 54 publications

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“…Low-energy data points include ACE data, taken during the solar minimum period 1997−1998(de Nolfo et al 2006. Close to submission of this paper, another ACE analysis was published (George et al 2009 Off-diagonal plots show the 2D marginalised posterior PDFs for the parameters in the same column and same line respectively.…”

Section: Sensitivity To the Choice Of The B/c Datasetmentioning

confidence: 99%

“…Unless specified otherwise, the reference B/C dataset used throughout the paper is denoted dataset F: it consists of i) lowenergy data taken by the IMP7-8 (Garcia-Munoz et al 1987), the Voyager 1&2 (Lukasiak et al 1999), and the ACE-CRIS (de Nolfo et al 2006) spacecrafts; ii) intermediate energies acquired by HEA0-3 data (Engelmann et al 1990); and iii) higher energy data from Spacelab (Swordy et al 1990) and the published CREAM data . Other existing data are discarded either because of their too large error bars, or because of their inconsistency with the above data (see Paper I).…”

Section: D1 B/c Ratiomentioning

confidence: 99%

“…We acknowledge the support of the French ANR (grant ANR-06-CREAM). The data for the elemental ratios come from the HEAO-3 (Engelmann et al 1990), Ulysses (Duvernois & Thayer 1996), and the ACE spacecrafts de Nolfo et al (2006). The published ACE data on Al/Mg and Cl/Ar (George et al 2009) were not used as Be/B is not provided.…”

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confidence: 99%

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A Markov Chain Monte Carlo technique to sample transport and source parameters of Galactic cosmic rays

Putze

Derome

Maurin

2010

A&A

145

191

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Context. Ongoing measurements of the cosmic radiation (nuclear, electronic, and γ-ray) are providing additional insight into cosmicray physics. A comprehensive picture of these data relies on an accurate determination of the transport and source parameters of propagation models. Aims. A Markov Chain Monte Carlo method is used to obtain these parameters in a diffusion model. By measuring the B/C ratio and radioactive cosmic-ray clocks, we calculate their probability density functions, placing special emphasis on the halo size L of the Galaxy and the local underdense bubble of size r h . We also derive the mean, best-fit model parameters and 68% confidence level for the various parameters, and the envelopes of other quantities. Methods. The analysis relies on the USINE code for propagation and on a Markov Chain Monte Carlo technique previously developed by ourselves for the parameter determination. Results. The B/C analysis leads to a most probable diffusion slope δ = 0.86 +0.04 −0.04 for diffusion, convection, and reacceleration, or δ = 0.234 +0.006 −0.005 for diffusion and reacceleration. As found in previous studies, the B/C best-fit model favours the first configuration, hence pointing to a high value for δ. These results do not depend on L, and we provide simple functions to rescale the value of the transport parameters to any L. A combined fit on B/C and the isotopic ratios ( 10 Be/ 9 Be, 26 Al/ 27 Al, 36 Cl/Cl) leads to L = 8 +8 −7 kpc and r h = 120 +20 −20 pc for the best-fit model. This value for r h is consistent with direct measurements of the local interstallar medium. For the model with diffusion and reacceleration, L = 4 +1 −1 kpc and r h = 3 +70 −3 pc (consistent with zero). We vary δ, because its value is still disputed. For the model with Galactic winds, we find that between δ = 0.2 and 0.9, L varies from O(0) to O(2) if r h is forced to be 0, but it otherwise varies from O(0) to O(1) (with r h ∼ 100 pc for all δ > ∼ 0.3). The results from the elemental ratios Be/B, Al/Mg, and Cl/Ar do not allow independent checks of this picture because these data are not precise enough. Conclusions. We showed the potential and usefulness of the Markov Chain Monte Carlo technique in the analysis of cosmic-ray measurements in diffusion models. The size of the diffusive halo depends crucially on the value of the diffusion slope δ, and also on the presence/absence of the local underdensity damping effect on radioactive nuclei. More precise data from ongoing experiments are expected to clarify this issue.

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Section: Sensitivity To the Choice Of The B/c Datasetmentioning

confidence: 99%

Section: D1 B/c Ratiomentioning

confidence: 99%

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A Markov Chain Monte Carlo technique to sample transport and source parameters of Galactic cosmic rays

Putze

Derome

Maurin

2010

A&A

145

191

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“…Concerning the experimental data used to fit the B/C ratio, as in Paper II, we use the following dataset (denoted F in Paper II), which consists of 31 B/C data points (see Fig. 5 of this paper): IMP7-8 (Garcia-Munoz et al 1987), Voyager 1&2 (Lukasiak et al 1999), ACE-CRIS (de Nolfo et al 2006), HEA0-3 (Engelmann et al 1990), Spacelab (Swordy et al 1990), and CREAM (Ahn et al 2008). …”

Section: Inputs and Default Configurationmentioning

confidence: 99%

Systematic uncertainties on the cosmic-ray transport parameters

Maurin

Putze

Derome

2010

A&A

117

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Context. The B/C ratio is used in cosmic-ray physics to constrain the transport parameters. However, from the same set of data, the various published values show a puzzling large scatter of these parameters. Aims. We investigate the impact of using different inputs (gas density and hydrogen fraction in the Galactic disc, source spectral shape, low-energy dependence of the diffusion coefficient, and nuclear fragmentation cross-sections) on the best-fit values of the transport parameters. We quantify the systematics produced when varying these inputs, and compare them to statistical uncertainties. We discuss the consequences for the slope of the diffusion coefficient δ. Methods. The analysis relies on the propagation code USINE interfaced with the Minuit minimisation routines. Results. We find the typical systematic uncertainties to be greater than the statistical ones. The several published values of δ (from 0.3 to 0.8) can be recovered when varying the low-energy shape of the diffusion coefficient and the convective wind strength. Models including a convective wind are characterised by δ 0.6, which cannot be reconciled with the expected theoretical values (1/3 and 1/2). However, from a statistical point of view (χ 2 analysis), models with both reacceleration and convection -hence large δ -are favoured. The next favoured models in line yield δ, which can be accommodated with 1/3 and 1/2, but require a strong upturn of the diffusion coefficient at low energy (and no convection). Conclusions. To date, using the best statistical tools, the transport parameter determination is still plagued by many unknowns at low energy (∼GeV/n). To disentangle all these configurations, measurements of the B/C ratio at TeV/n energies and/or combination with other secondary-to-primary ratios is necessary.

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“…As secondary component or even tertiary (since it can also be produced by the spallation of secondaries) the abundance of lithium is sensitive to the propagation history of cosmic rays and them can be used to constrain the parameters describing the diffusion, convection or reacceleration of cosmic rays in the Galaxy [1]. Previous measurements of lithium flux as been reported from balloon and space experiments [2].…”

Section: Introductionmentioning

confidence: 99%

Precision Measurement of Lithium Flux in Cosmic Rays with the Alpha Magnetic Spectrometer on the International Space Station

Derome¹

2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

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Observations of the Li, Be, and B isotopes and constraints on cosmic-ray propagation

Cited by 59 publications

References 54 publications

A Markov Chain Monte Carlo technique to sample transport and source parameters of Galactic cosmic rays

A Markov Chain Monte Carlo technique to sample transport and source parameters of Galactic cosmic rays

Systematic uncertainties on the cosmic-ray transport parameters

Precision Measurement of Lithium Flux in Cosmic Rays with the Alpha Magnetic Spectrometer on the International Space Station

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