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

Journal Article · Wed Mar 04 00:00:00 EST 2009 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3108785· OSTI ID:21289456

Patel, N R; Greife, U ^[1]; Rehm, K E; Greene, J; Henderson, D; Jiang, C L; Kay, B P; Lee, H Y; Pardo, R; Teh, K ^[2]; Deibel, C M; Notani, M ^[2]; Marley, S T ^[2]; Tang, X D ^[3]

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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)

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.

• OSTI ID: 21289456
• Journal Information: AIP Conference Proceedings, Vol. 1098, 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); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

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