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Title: The {sup 95}Zr( n , γ ){sup 96}Zr Cross Section from the Surrogate Ratio Method and Its Effect on s -process Nucleosynthesis

Abstract

The {sup 95}Zr( n , γ ){sup 96}Zr reaction cross section is crucial in the modeling of s -process nucleosynthesis in asymptotic giant branch stars because it controls the operation of the branching point at the unstable {sup 95}Zr and the subsequent production of {sup 96}Zr. We have carried out the measurement of the {sup 94}Zr({sup 18}O, {sup 16}O) and {sup 90}Zr({sup 18}O, {sup 16}O) reactions and obtained the γ -decay probability ratio of {sup 96}Zr* and {sup 92}Zr* to determine the {sup 95}Zr( n , γ ){sup 96}Zr reaction cross sections with the surrogate ratio method. Our deduced Maxwellian-averaged cross section of 66 ± 16 mb at 30 keV is close to the value recommended by Bao et al., but 30% and more than a factor of two larger than the values proposed by Toukan and Käppeler and Lugaro et al., respectively, and routinely used in s -process models. We tested the new rate in stellar models with masses between 2 and 6 M {sub ⊙} and metallicities of 0.014 and 0.03. The largest changes—up to 80% variations in {sup 96}Zr—are seen in models of mass 3–4 M {sub ⊙}, where the {sup 22}Ne neutron source is mildly activated.more » The new rate can still provide a match to data from meteoritic stardust silicon carbide grains, provided that the maximum mass of the parent stars is below 4 M {sub ⊙}, for a metallicity of 0.03.« less

Authors:
; ; ; ; ; ; ; ; ; ; ;  [1]; ; ; ; ;  [2];  [3];  [4];  [5]
  1. China Institute of Atomic Energy, P.O. Box 275(10), Beijing 102413 (China)
  2. Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan)
  3. Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, 1121 Budapest (Hungary)
  4. Monash Centre for Astrophysics, School of Physics and Astronomy, Monash University, Clayton, VIC 3800 (Australia)
  5. Institute for Nuclear Research (ATOMKI), H-4001 Debrecen (Hungary)
Publication Date:
OSTI Identifier:
22679755
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 848; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; BRANCHING RATIO; CROSS SECTIONS; GAMMA DECAY; MASS; NEON 22; NEUTRON REACTIONS; NEUTRON SOURCES; NUCLEAR REACTIONS; NUCLEOSYNTHESIS; OXYGEN 16; OXYGEN 18; S PROCESS; SIMULATION; STARS; ZIRCONIUM 90; ZIRCONIUM 92; ZIRCONIUM 94; ZIRCONIUM 95; ZIRCONIUM 96

Citation Formats

Yan, S.Q., Li, Z.H., Wang, Y.B., Su, J., Li, Y. J., Han, Y.L., Shen, Y.P., Guo, B., Zeng, S., Lian, G., Chen, Y.S., Liu, W.P., Nishio, K., Makii, H., Nishinaka, I., Hirose, K., Orlandi, R., Lugaro, M., Karakas, A. I., and Mohr, P., E-mail: panyu@ciae.ac.cn, E-mail: maria.lugaro@csfk.mta.hu. The {sup 95}Zr( n , γ ){sup 96}Zr Cross Section from the Surrogate Ratio Method and Its Effect on s -process Nucleosynthesis. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8C74.
Yan, S.Q., Li, Z.H., Wang, Y.B., Su, J., Li, Y. J., Han, Y.L., Shen, Y.P., Guo, B., Zeng, S., Lian, G., Chen, Y.S., Liu, W.P., Nishio, K., Makii, H., Nishinaka, I., Hirose, K., Orlandi, R., Lugaro, M., Karakas, A. I., & Mohr, P., E-mail: panyu@ciae.ac.cn, E-mail: maria.lugaro@csfk.mta.hu. The {sup 95}Zr( n , γ ){sup 96}Zr Cross Section from the Surrogate Ratio Method and Its Effect on s -process Nucleosynthesis. United States. doi:10.3847/1538-4357/AA8C74.
Yan, S.Q., Li, Z.H., Wang, Y.B., Su, J., Li, Y. J., Han, Y.L., Shen, Y.P., Guo, B., Zeng, S., Lian, G., Chen, Y.S., Liu, W.P., Nishio, K., Makii, H., Nishinaka, I., Hirose, K., Orlandi, R., Lugaro, M., Karakas, A. I., and Mohr, P., E-mail: panyu@ciae.ac.cn, E-mail: maria.lugaro@csfk.mta.hu. Fri . "The {sup 95}Zr( n , γ ){sup 96}Zr Cross Section from the Surrogate Ratio Method and Its Effect on s -process Nucleosynthesis". United States. doi:10.3847/1538-4357/AA8C74.
@article{osti_22679755,
title = {The {sup 95}Zr( n , γ ){sup 96}Zr Cross Section from the Surrogate Ratio Method and Its Effect on s -process Nucleosynthesis},
author = {Yan, S.Q. and Li, Z.H. and Wang, Y.B. and Su, J. and Li, Y. J. and Han, Y.L. and Shen, Y.P. and Guo, B. and Zeng, S. and Lian, G. and Chen, Y.S. and Liu, W.P. and Nishio, K. and Makii, H. and Nishinaka, I. and Hirose, K. and Orlandi, R. and Lugaro, M. and Karakas, A. I. and Mohr, P., E-mail: panyu@ciae.ac.cn, E-mail: maria.lugaro@csfk.mta.hu},
abstractNote = {The {sup 95}Zr( n , γ ){sup 96}Zr reaction cross section is crucial in the modeling of s -process nucleosynthesis in asymptotic giant branch stars because it controls the operation of the branching point at the unstable {sup 95}Zr and the subsequent production of {sup 96}Zr. We have carried out the measurement of the {sup 94}Zr({sup 18}O, {sup 16}O) and {sup 90}Zr({sup 18}O, {sup 16}O) reactions and obtained the γ -decay probability ratio of {sup 96}Zr* and {sup 92}Zr* to determine the {sup 95}Zr( n , γ ){sup 96}Zr reaction cross sections with the surrogate ratio method. Our deduced Maxwellian-averaged cross section of 66 ± 16 mb at 30 keV is close to the value recommended by Bao et al., but 30% and more than a factor of two larger than the values proposed by Toukan and Käppeler and Lugaro et al., respectively, and routinely used in s -process models. We tested the new rate in stellar models with masses between 2 and 6 M {sub ⊙} and metallicities of 0.014 and 0.03. The largest changes—up to 80% variations in {sup 96}Zr—are seen in models of mass 3–4 M {sub ⊙}, where the {sup 22}Ne neutron source is mildly activated. The new rate can still provide a match to data from meteoritic stardust silicon carbide grains, provided that the maximum mass of the parent stars is below 4 M {sub ⊙}, for a metallicity of 0.03.},
doi = {10.3847/1538-4357/AA8C74},
journal = {Astrophysical Journal},
number = 2,
volume = 848,
place = {United States},
year = {Fri Oct 20 00:00:00 EDT 2017},
month = {Fri Oct 20 00:00:00 EDT 2017}
}