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Title: Experiments to Further the Understanding of the Triple-Alpha Process in Hot Astrophysical Scenarios

Abstract

In astrophysics, the first excited 0{sup +} state of {sup 12}C at 7.654 MeV (Hoyle state) is the most important in the triple-{alpha} process for carbon nucleosynthesis. In explosive scenarios like supernovae, where temperatures of several 10{sup 9} K are achieved, the interference of the Hoyle state with the second 0{sup +} state located at 10.3 MeV in {sup 12}C becomes significant. The recent NACRE compilation of astrophysical reaction rates assumes a 2{sup +} resonance at 9.1 MeV for which no experimental evidence exists. Thus, it is critical to explore in more detail the 7-10 MeV excitation energy region, especially the minimum between the two 0{sup +} resonances for carbon nucleosynthesis. The states in {sup 12}C were populated through the {beta}-decay of {sup 12}B and {sup 12}N produced at the ATLAS (Argonne Tandem Linac Accelerator System) in-flight facility. The decay of {sup 12}C into three alphas is detected in a Frisch grid twin ionization chamber, acting as a low-threshold calorimeter. This minimizes the effects of {beta}-summing and allowed us to investigate the minimum above the Hoyle state with much higher accuracy than previously possible. A detailed data analysis will include an R-matrix fit to determine an upper limit on themore » 2{sup +} resonance width.« less

Authors:
;  [1]; ; ; ; ; ; ; ;  [2]; ;  [2];  [2];  [3]
  1. Department of Physics, Colorado School of Mines, Golden, CO 80401 (United States)
  2. Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)
  3. Department of Physics, University of Notre Dame, IN 46556 (United States)
Publication Date:
OSTI Identifier:
21289456
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 1098; Journal Issue: 1; Conference: FUSION08: International conference on new aspects of heavy ion collisions near the Coulomb barrier, Chicago, IL (United States), 22-26 Sep 2008; Other Information: DOI: 10.1063/1.3108785; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ALPHA DECAY; ASTROPHYSICS; BETA DECAY; BORON 12; CARBON 12; CLUSTER MODEL; DATA ANALYSIS; EXCITATION; EXCITED STATES; MEV RANGE; NITROGEN 12; NUCLEAR STRUCTURE; NUCLEOSYNTHESIS; R MATRIX

Citation Formats

Patel, N R, Greife, U, Rehm, K E, Greene, J, Henderson, D, Jiang, C L, Kay, B P, Lee, H Y, Pardo, R, Teh, K, Deibel, C M, Notani, M, Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824, Marley, S T, Physics Department, Western Michigan University, Kalamazoo, MI 49008, and Tang, X D. Experiments to Further the Understanding of the Triple-Alpha Process in Hot Astrophysical Scenarios. United States: N. p., 2009. Web. doi:10.1063/1.3108785.
Patel, N R, Greife, U, Rehm, K E, Greene, J, Henderson, D, Jiang, C L, Kay, B P, Lee, H Y, Pardo, R, Teh, K, Deibel, C M, Notani, M, Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824, Marley, S T, Physics Department, Western Michigan University, Kalamazoo, MI 49008, & Tang, X D. Experiments to Further the Understanding of the Triple-Alpha Process in Hot Astrophysical Scenarios. United States. doi:10.1063/1.3108785.
Patel, N R, Greife, U, Rehm, K E, Greene, J, Henderson, D, Jiang, C L, Kay, B P, Lee, H Y, Pardo, R, Teh, K, Deibel, C M, Notani, M, Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824, Marley, S T, Physics Department, Western Michigan University, Kalamazoo, MI 49008, and Tang, X D. Wed . "Experiments to Further the Understanding of the Triple-Alpha Process in Hot Astrophysical Scenarios". United States. doi:10.1063/1.3108785.
@article{osti_21289456,
title = {Experiments to Further the Understanding of the Triple-Alpha Process in Hot Astrophysical Scenarios},
author = {Patel, N R and Greife, U and Rehm, K E and Greene, J and Henderson, D and Jiang, C L and Kay, B P and Lee, H Y and Pardo, R and Teh, K and Deibel, C M and Notani, M and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 and Marley, S T and Physics Department, Western Michigan University, Kalamazoo, MI 49008 and Tang, X D},
abstractNote = {In astrophysics, the first excited 0{sup +} state of {sup 12}C at 7.654 MeV (Hoyle state) is the most important in the triple-{alpha} process for carbon nucleosynthesis. In explosive scenarios like supernovae, where temperatures of several 10{sup 9} K are achieved, the interference of the Hoyle state with the second 0{sup +} state located at 10.3 MeV in {sup 12}C becomes significant. The recent NACRE compilation of astrophysical reaction rates assumes a 2{sup +} resonance at 9.1 MeV for which no experimental evidence exists. Thus, it is critical to explore in more detail the 7-10 MeV excitation energy region, especially the minimum between the two 0{sup +} resonances for carbon nucleosynthesis. The states in {sup 12}C were populated through the {beta}-decay of {sup 12}B and {sup 12}N produced at the ATLAS (Argonne Tandem Linac Accelerator System) in-flight facility. The decay of {sup 12}C into three alphas is detected in a Frisch grid twin ionization chamber, acting as a low-threshold calorimeter. This minimizes the effects of {beta}-summing and allowed us to investigate the minimum above the Hoyle state with much higher accuracy than previously possible. A detailed data analysis will include an R-matrix fit to determine an upper limit on the 2{sup +} resonance width.},
doi = {10.1063/1.3108785},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 1098,
place = {United States},
year = {2009},
month = {3}
}