All Outputs (18)

MESA and NuGrid simulations of classical nova outbursts and nucleosynthesis (2014)
Presentation / Conference Contribution
Pignatari, M., Denisenkov, P. A., Herwig, F., & Truran, J. MESA and NuGrid simulations of classical nova outbursts and nucleosynthesis

Classical novae are the results of surface thermonuclear explosions of hydrogen accreted by white dwarfs (WDs) from their low-mass main-sequence or red-giant binary companions. Chemical composition analysis of their ejecta shows that nova outbursts o... Read More about MESA and NuGrid simulations of classical nova outbursts and nucleosynthesis.

New insights on Ba overabundance in open clusters : evidence for the intermediate neutron-capture process at play? (2014)
Journal Article
Mishenina, T., Pignatari, M., Carraro, G., Kovtyukh, V., Monaco, L., Korotin, S., Shereta, E., Yegorova, I., & Herwig, F. (2015). New insights on Ba overabundance in open clusters : evidence for the intermediate neutron-capture process at play?. Monthly notices of the Royal Astronomical Society, 446(4), 3651-3668. https://doi.org/10.1093/mnras/stu2337

Recently, an increasing number of studies were devoted to measure the abundances of neutron-capture elements heavier than iron in stars belonging to Galactic Open Clusters (OCs). OCs span a sizeable range in metallicity (−0.6 ≤ [Fe/H] ≤ +0.4), and th... Read More about New insights on Ba overabundance in open clusters : evidence for the intermediate neutron-capture process at play?.

Stellar neutron capture cross sections of ²⁰ ²¹ ²²Ne (2014)
Journal Article
Heil, M., Plag, R., Uberseder, E., Gallino, R., Bisterzo, S., Juseviciute, A., Käppeler, F., Lederer, C., Mengoni, A., & Pignatari, M. (2014). Stellar neutron capture cross sections of ²⁰ ²¹ ²²Ne. Physical Review C, 90(4), 045804-1-045804-11. https://doi.org/10.1103/PhysRevC.90.045804

The stellar (n,γ) cross sections of the Ne isotopes are important for a number of astrophysical quests, i.e., for the interpretation of abundance patterns in presolar material or with respect to the s-process neutron balance in red giant stars. This... Read More about Stellar neutron capture cross sections of ²⁰ ²¹ ²²Ne.

High-resolution abundance analysis of red giants in the globular cluster NGC 6522 (2014)
Journal Article
Barbuy, B., Chiappini, C., Cantelli, E., Depagne, E., Pignatari, M., Hirschi, R., Cescutti, G., Ortolani, S., Hill, V., Zoccali, M., Minniti, D., Trevisan, M., Bica, E., & Gómez, A. (2014). High-resolution abundance analysis of red giants in the globular cluster NGC 6522. Astronomy and Astrophysics, 570, A76. https://doi.org/10.1051/0004-6361/201424311

© 2014 ESO. Context. The [Sr/Ba] and [Y/Ba] scatter observed in some galactic halo stars that are very metal-poor and in a few individual stars of the oldest known Milky Way globular cluster NGC 6522 have been interpreted as evidence of early enrich... Read More about High-resolution abundance analysis of red giants in the globular cluster NGC 6522.

Neutron Capture Reactions on Fe and Ni Isotopes for the Astrophysical s-process (2014)
Journal Article
Lederer, C., Giubrone, G., Massimi, C., Žugec, P., Barbagallo, M., Colonna, N., Domingo-Pardo, C., Guerrero, C., Gunsing, F., Käppeler, F., Tain, J., Altstadt, S., Andrzejewski, J., Audouin, L., Bécares, V., Bečvář, F., Belloni, F., Berthoumieux, E., Billowes, J., Boccone, V., …Schumann, D. (2014). Neutron Capture Reactions on Fe and Ni Isotopes for the Astrophysical s-process. Nuclear data sheets, 120, 201-204. https://doi.org/10.1016/j.nds.2014.07.046

Neutron capture cross sections in the keV neutron energy region are the key nuclear physics input to study the astrophysical slow neutron capture process. In the past years, a series of neutron capture cross section measurements has been performed at... Read More about Neutron Capture Reactions on Fe and Ni Isotopes for the Astrophysical s-process.

Measurement of the MACS of 159Tb(n, γ) at kT=30 keV by Activation (2014)
Journal Article
Praena, J., Mastinu, P., Pignatari, M., Quesada, J., Capote, R., & Morilla, Y. (2014). Measurement of the MACS of 159Tb(n, γ) at kT=30 keV by Activation. Nuclear data sheets, 120, 205-207. https://doi.org/10.1016/j.nds.2014.07.047

The measurement of the Maxwellian-Averaged Cross-Section (MACS) of the 159 Tb(n, γ) reaction at kT=30 keV by the activation technique is presented. An innovative method for the generation of Maxwellian neutron spectra at kT=30 keV is used. An experim... Read More about Measurement of the MACS of 159Tb(n, γ) at kT=30 keV by Activation.

MESA and NuGrid simulations of classical novae: CO and ONe nova nucleosynthesis (2014)
Journal Article
Denissenkov, P. A., Truran, J. W., Pignatari, M., Trappitsch, R., Ritter, C., Herwig, F., Battino, U., Setoodehnia, K., & Paxton, B. (2014). MESA and NuGrid simulations of classical novae: CO and ONe nova nucleosynthesis. Monthly notices of the Royal Astronomical Society, 442(3), 2058-2074. https://doi.org/10.1093/mnras/stu1000

Classical novae are the result of thermonuclear flashes of hydrogen accreted by CO or ONe white dwarfs, leading eventually to the dynamic ejection of the surface layers. These are observationally known to be enriched in heavy elements, such as C, O a... Read More about MESA and NuGrid simulations of classical novae: CO and ONe nova nucleosynthesis.

Measurement of the 241Am and the 243Am Neutron Capture Cross Sections at the n_TOF Facility at CERN (2014)
Journal Article
Riego, A., Reifarth, R., Rauscher, T., Sarmento, R., Rubbia, C., Roman, F., Schumann, D., Schmidt, S., Schillebeeckx, P., Wallner, A., Vlastou, R., Vlachoudis, V., Vermeulen, M., Versaci, R., Ventura, A., Vaz, P., Variale, V., Vannini, G., Valenta, S., Tsinganis, A., …Schumann, D. (2014). Measurement of the 241Am and the 243Am Neutron Capture Cross Sections at the n_TOF Facility at CERN. Nuclear data sheets, 119, 65-68. https://doi.org/10.1016/j.nds.2014.08.020

The capture cross sections of 241 Am and 243 Am were measured at the n TOF facility at CERN in the epithermal energy range with a BaF 2 Total Absorption Calorimeter. A preliminary analysis of the 241 Am and a complete analysis of the 243 Am measureme... Read More about Measurement of the 241Am and the 243Am Neutron Capture Cross Sections at the n_TOF Facility at CERN.

Measurement of the neutron capture cross section of the c235U with the CERN n_TOF total absorption calorimeter and a fission tagging based on micromegas detectors (2014)
Journal Article
Žugec, P., Wright, T., Weiß, C., Weigand, M., Ware, T., Wallner, A., Vlastou, R., Vlachoudis, V., Vermeulen, M., Versaci, R., Balibrea, J., Mendoza, E., Cano-Ott, D., Guerrero, C., Berthoumieux, E., Altstadt, S., Andrzejewski, J., Audouin, L., Barbagallo, M., Bécares, V., …Tsinganis, A. (2014). Measurement of the neutron capture cross section of the c235U with the CERN n_TOF total absorption calorimeter and a fission tagging based on micromegas detectors. Nuclear data sheets, 119, 10-13. https://doi.org/10.1016/j.nds.2014.08.005

© 2014 Elsevier Inc. All rights reserved. Current and future nuclear technologies require more accurate nuclear data on (n,γ) cross sections and the α-ratios of fissile isotopes. Their measurement presents several difficulties, mainly related to the... Read More about Measurement of the neutron capture cross section of the c235U with the CERN n_TOF total absorption calorimeter and a fission tagging based on micromegas detectors.

Measurement of the 54,57Fe (n,γ) cross section in the resolved resonance region at CERN n_TOF (2014)
Journal Article
Valenta, S., Vannini, G., Variale, V., Vaz, P., Ventura, A., Versaci, R., Wright, T., Ware, T., Weiß, C., Weigand, M., Žugec, P., Giubrone, G., Domingo-Pardo, C., Taín, J. L., Lederer, C., Altstadt, S., Andrzejewski, J., Audouin, L., Barbagallo, M., Bécares, V., …Versaci, R. (2014). Measurement of the 54,57Fe (n,γ) cross section in the resolved resonance region at CERN n_TOF. Nuclear data sheets, 119, 117-120. https://doi.org/10.1016/j.nds.2014.08.033

© 2014 Elsevier Inc. 54 Fe and 57 Fe are stable iron isotopes, which play an important role in the nucleosynthesis of theslow neutron capture process (s process). In addition, these nuclei are present in many structuralmaterials, and therefore, the k... Read More about Measurement of the 54,57Fe (n,γ) cross section in the resolved resonance region at CERN n_TOF.

High-precision measurement of the 238U (n,γ) cross section with the Total Absorption Calorimeter (TAC) at n_TOF, CERN (2014)
Journal Article
Wright, T., Guerrero, C., Billowes, J., Ware, T., Cano-Ott, D., Mendoza, E., Massimi, C., Mingrone, F., Gunsing, F., Berthoumieux, E., Lampoudis, C., Altstadt, S., Andrzejewski, J., Audouin, L., Barbagallo, M., Bécares, V., Bečvář, F., Belloni, F., Boccone, V., Bosnar, D., …Vermeulen, M. (2014). High-precision measurement of the 238U (n,γ) cross section with the Total Absorption Calorimeter (TAC) at n_TOF, CERN. Nuclear data sheets, 119, 26-30. https://doi.org/10.1016/j.nds.2014.08.009

The neutron capture cross section of 238 U is fundamental to the design and operation of current reactors and future fast nuclear reactors, and thus must be measured to a high level of accuracy. An experiment has been performed at the CERN n TOF faci... Read More about High-precision measurement of the 238U (n,γ) cross section with the Total Absorption Calorimeter (TAC) at n_TOF, CERN.

Investigation of neutron-induced reactions at n_TOF: An overview of the 2009-2012 experimental program (2014)
Journal Article
Guerrero, C., Altstadt, S., Andrzejewski, J., Audouin, L., Barbagallo, M., Bécares, V., Bečvář, F., Belloni, F., Berthoumieux, E., Billowes, J., Boccone, V., Bosnar, D., Brugger, M., Calviani, M., Calviño, F., Cano-Ott, D., Carrapiço, C., Cerutti, F., Chiaveri, E., Chin, M., …Tarrío, D. (2014). Investigation of neutron-induced reactions at n_TOF: An overview of the 2009-2012 experimental program. Nuclear data sheets, 119, 5-9. https://doi.org/10.1016/j.nds.2014.08.004

The neutron time-of-flight facility n TOF is operating at CERN (Switzerland) since 2001, having started in 2009 a new campaign with an upgraded spallation target. The ambitious program carried out includes a large number of experiments in nuclear tec... Read More about Investigation of neutron-induced reactions at n_TOF: An overview of the 2009-2012 experimental program.

Barium isotopic composition of mainstream silicon carbides from Murchison : constraints for s-process nucleosynthesis in asymptotic giant branch stars (2014)
Journal Article
Savina, M. R., Pellin, M. J., Willingham, D. G., Pignatari, M., Bisterzo, S., Cristallo, S., Dauphas, N., Davis, A. M., Gallino, R., Gyngard, F., Herwig, F., Liu, N., Pellin, M. J., Savina, M., Straniero, O., & Willingham, D. (2014). Barium isotopic composition of mainstream silicon carbides from Murchison : constraints for s-process nucleosynthesis in asymptotic giant branch stars. The Astrophysical journal, 786(1), 66. https://doi.org/10.1088/0004-637x/786/1/66

We present barium, carbon, and silicon isotopic compositions of 38 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly effective in removing barium contamination. Strong depletions in δ(138... Read More about Barium isotopic composition of mainstream silicon carbides from Murchison : constraints for s-process nucleosynthesis in asymptotic giant branch stars.

Current quests in nucleosynthesis: Present and future neutron-induced reaction measurements (2014)
Journal Article
Praena, J., Pignatari, M., Mastinu, P., Martín-Hernández, G., Prete, G., Quesada, J., & Sabaté-Gilarte, M. (2014). Current quests in nucleosynthesis: Present and future neutron-induced reaction measurements. EPJ Web of Conferences, 66, 07022. https://doi.org/10.1051/epjconf/20146607022

We present some open questions in nucleosynthesis focused on the measurement of relevant neutron capture cross-sections and on new experimental methods. We review the recent 63 Ni(n,γ) experiment carried out at the n-TOF facility at CERN and its astr... Read More about Current quests in nucleosynthesis: Present and future neutron-induced reaction measurements.

Ni62(n,γ) and Ni63(n,γ) cross sections measured at the n_TOF facility at CERN (2014)
Journal Article
Lederer, C., Massimi, C., Berthoumieux, E., Colonna, N., Dressler, R., Guerrero, C., Gunsing, F., Käppeler, F., Kivel, N., Pignatari, M., Reifarth, R., Schumann, D., Wallner, A., Altstadt, S., Andriamonje, S., Andrzejewski, J., Audouin, L., Barbagallo, M., Bécares, V., Bečvář, F., …Tassan-Got, L. (2014). Ni62(n,γ) and Ni63(n,γ) cross sections measured at the n_TOF facility at CERN. Physical Review C - Nuclear Physics, 89(2), Article 025810. https://doi.org/10.1103/physrevc.89.025810

The cross section of the Ni62(n,γ) reaction was measured with the time-of-flight technique at the neutron time-of-flight facility n-TOF at CERN. Capture kernels of 42 resonances were analyzed up to 200 keV neutron energy and Maxwellian averaged cross... Read More about Ni62(n,γ) and Ni63(n,γ) cross sections measured at the n_TOF facility at CERN.

Chemical abundances in bright giants of the globular cluster M62 (NGC 6266) (2014)
Journal Article
Yong, D., Alves Brito, A., Da Costa, G. S., Alonso-García, J., Karakas, A. I., Pignatari, M., Roederer, I. U., Aoki, W., Fishlock, C. K., Grundahl, F., & Norris, J. E. (2014). Chemical abundances in bright giants of the globular cluster M62 (NGC 6266). Monthly notices of the Royal Astronomical Society, 439(3), 2638-2650. https://doi.org/10.1093/mnras/stu118

With the exception of Terzan 5, all the Galactic globular clusters that possess significant metallicity spreads, such as ω Cen and M22, are preferentially the more luminous clusters with extended horizontal branches. Here we present radial velocities... Read More about Chemical abundances in bright giants of the globular cluster M62 (NGC 6266).

Experimental neutron capture data of 58 Ni from the CERN n-TOF facility (2014)
Journal Article
Žugec, P., Barbagallo, M., Colonna, N., Bosnar, D., Altstadt, S., Andrzejewski, J., Audouin, L., Bécares, V., Bečvář, F., Belloni, F., Berthoumieux, E., Billowes, J., Boccone, V., Brugger, M., Calviani, M., Calvino, F., Cano-Ott, D., Carrapiço, C., Cerutti, F., Chiaveri, E., …Wright, T. J. (2014). Experimental neutron capture data of 58 Ni from the CERN n-TOF facility. Physical Review C - Nuclear Physics, 89(1), 014605-1-014605-9. https://doi.org/10.1103/physrevc.89.014605

The ⁵⁸Ni(n,γ) cross section has been measured at the neutron time of flight facility n_TOF at CERN, in the energy range from 27 meV up to 400 keV. In total, 51 resonances have been analyzed up to 122 keV. Maxwellian averaged cross sections (MACS) hav... Read More about Experimental neutron capture data of 58 Ni from the CERN n-TOF facility.

Impact of the uncertainty in α-captures on 22Ne on the weak s-process in massive stars (2014)
Presentation / Conference Contribution
Nishimura, N., Hirschi, R., Pignatari, M., Herwig, F., Beard, M., Imbriani, G., Görres, J., Deboer, R. J., & Wiescher, M. Impact of the uncertainty in α-captures on 22Ne on the weak s-process in massive stars. Presented at ORIGIN OF MATTER AND EVOLUTION OF GALAXIES 2013: Proceedings of the 12th International Symposium on Origin of Matter and Evolution of Galaxies (OMEG12), Tsukuba, Japan

Massive stars at solar metallicity contribute to the production of heavy elements with atomic masses between A = 60 and A = 90 via the so-called weak s-process (which takes place during core He and shell C burning phases). Furthermore, recent studies... Read More about Impact of the uncertainty in α-captures on 22Ne on the weak s-process in massive stars.