Fast-neutron scattering from indium

Smith, A.B.; Guenther, P.T.; Whalen, J.; Heerden, I.J. van; McMurray, William

doi:10.1088/0305-4616/11/1/018

Cited by 30 publications

(18 citation statements)

References 34 publications

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“…Collisional data are the same as those used by Drake (1991). The two Ca atomic models differ in the line damping parameters, which are respectively from the Kurucz atomic database (Kurucz & Bell 1995) (model M 1) and from Smith & Drake (1990) (model M 2). Moreover, the model containing the Kurucz damping constants also includes collisional data from for the Ca  2 P 3/2 ↔ 2 P 1/2 transition.…”

Section: Model Calculations and Solar Testmentioning

confidence: 99%

“…The first attempts to analyse the sensitivity of the Ca  IRT strength to the atmospheric parameters were restricted to the line wings. In this sense, Smith & Drake (1987, 1990 using Local Thermodynamic Equilibrium (LTE) models concluded that the dependence on metallicity should be larger than that reported by the empirical studies, and that effective temperatures had a non-negligible effect. Erdelyi-Mendes & Barbuy (1991), also using LTE models, extended the analysis to cooler stars and included the significant contribution of molecular bands.…”

Section: Introductionmentioning

confidence: 96%

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The Ca II Infrared Triplet as a stellar activity diagnostic

Andretta¹,

Busà

Gomez³

et al. 2005

A&A

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Abstract. This work is part of a larger project on the study of activity in stars of spectral type similar to, or later than the Sun, from PMS to ZAMS, based on the analysis of the high resolution Ca  InfraRed Triplet (Ca  IRT: λ = 8498, 8542, 8662 Å) observed profiles. Here, a preliminary study on the diagnostic power of these calcium lines has been performed by means of NLTE calculations of the line profiles with an approximate treatment of UV line-blanketing, for a grid of photospheric models with T eff = 4200, 5200, 6200 K, log g = 4.0, 4.5, 5.0 and [A/H] = 0.0, −1.0, −2.0. We used these calculations to estimate the sensitivity of the profiles to changes in stellar parameters and the effect of departures from LTE. As found by other authors, the Ca  triplet NLTE EQWs (equivalent widths) are quite sensitive to photospheric parameters, in particular to T eff and [A/H]. On the other hand, we find that the dependence of the Ca  triplet lines central depression (CD = 1-central relative flux) on log g and T eff , and to a lesser extent to [A/H], is very weak. The departure from LTE is negligible when we consider EQWs, unless very metal-poor atmospheres are considered, while CDs can be affected by NLTE by more than 20%. This analysis indicates that in the use of these lines as activity indicators (where the details of the line profile in the core are important), a NLTE treatment is required. Furthermore, we show that a new chromospheric indicator, which we denote R IRT , can be derived from measurements of Ca  IRT line central depressions, provided that rotational broadening is taken into proper account. In order to facilitate the use of the Ca  IRT lines as activity diagnostics, we give interpolation formulae for estimating line CDs within the range of stellar parameters of our NLTE calculations.

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Section: Model Calculations and Solar Testmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

The Ca II Infrared Triplet as a stellar activity diagnostic

Andretta¹,

Busà

Gomez³

et al. 2005

A&A

View full text Add to dashboard Cite

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“…The relatively small absorption strength is typical of potentials applicable to regions near shell closures [12,35]. The general trends of OM parameters in this mass-energy region are discussed in [36]. The above model is qualitatively descriptive of the observed inelastic-scattering cross sections, as illustrated in Figs.…”

Section: Physical Interpretation and Modelingmentioning

confidence: 72%

Neutron total, scattering and inelastic Gamma-ray cross sections of yttrium at few MeV energies

et al. 1984

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Neutron total, scattering and (n; n',V) cross sections of elemental yttrium (89y) were measured in the few-MeV region. The neutron total-cross-section measurements were made with broad resolutions from ~0.5 to 4.2MeV in steps of <0.1MeV. Neutron elastic-and inelastic-scattering cross sections were measured from ~1.5 to 4.0MeV, at incident-neutron energy intervals of ~50keV and at ten or more scattering angles distributed between 20 and 160 degrees using neutron detection. Inelastic-scattering cross sections were also determined using the (n; n', ~) reaction at incident energies from 1.6 to 3.8 MeV at intervals of 0.1 MeV. Gamma-rays and/or inelastically-scattered neutrons were observed corresponding to the excitation of levels at: 909.0_+0.5, 1,507.4 +0.3, 1,744.5+0.3, 2,222.6_+0.5, 2,530_+0.8, 2,566.4_+1.0, 2,622.5+_1.0, 2,871.9_+1.5, 2,880. 6_+2.0, 3,067.0_+2.0, 3,107.0_+2.0, 3,140.0_+2.0, 3,410.0+2.0, 3,450.0_+2.0, 3,504.0 _+1.5, 3,514.0_+2.0, 3,556.0+_2.0, 3,619.0+3.0, 3,629.0_+3.0 and 3,715.0 _+ 3.0 keV. The experimental results are discussed in terms of the spherical-optical-statistical, coupledchannels, and core-coupling models, and in the context of previously reported excitedlevel structure.Nuclear Reactions: Measured at(n ) 0.5 to 4.2MeV, da(n)/df2 and d~r(n')/df2 1.5 to 4.0 MeV, and a(n; n', V) 1.6 to 3.8 MeV for elemental yttrium. Spherical-optical-statistical, coupled-channels and core-coupling models and level structure discussed.

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“…The calculated cross section for the 535.6 keV level can be compared with some neutron measurements(*"- (27), and the comparison is shown in Fig. 9.…”

Section: Comparison With Experimental Datamentioning

confidence: 99%

Validity of DWBA Calculations for Neutron Inelastic Scattering from Molybdenum Isotopes

Kawano

Watanabe

Kawai

1998

Journal of Nuclear Science and Technology

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Neutron inelastic scattering cross sections for molybdenum isotopes are calculated with the DWBA and the coupled-channels methods. Anomalous enhancement of the DWBA cross sections neax the threshold energy appears when the adopted optical potential has a shallow imaginary part. Calculations with some simplified optical potentials indicate that the enhancement can be related with the ywave strength, and it is found that the problem comes from the optical potential used.When an adopted optical potential to the DWBA calculation is physically reasonable, differences between the calculated cross sections with the DWBA and those with the coupled-channels theory are small. Experimental data of "MO, 98ht0 and looMo are well reproduced by the calculated cross sections with the DWBA and the Hauser-Feshbach-bloldauer statistical model, and it is concluded that the DWBA is an appropriate method to evaluate cross sections of inelastic scattering from the molybdenum isotopes.

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Fast-neutron scattering from indium

Cited by 30 publications

References 34 publications

The Ca II Infrared Triplet as a stellar activity diagnostic

The Ca II Infrared Triplet as a stellar activity diagnostic

Neutron total, scattering and inelastic Gamma-ray cross sections of yttrium at few MeV energies

Validity of DWBA Calculations for Neutron Inelastic Scattering from Molybdenum Isotopes

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