Nuclear Astrophysics Measurements with Radioactive Ion Beams

We are using high-quality, intense beams of radioactive nuclei from the Holifield Radioactive Ion Beam Facility (HRIBF) to make precision measurements of crucial nuclear reactions which occur in stellar explosions such as novae and X-ray bursts. These explosions serve to synthesize heavy elements from light elements, generate enormous energies, and are responsible for the evolution of cataclysmic binary star systems. Accelerated radioactive nuclear beams are required for these studies because the extremely high temperatures and densities in stellar explosions lead to the synthesis of, and subsequent nuclear reactions with, radioactive isotopes. Direct measurements of these reactions with HRIBF beams provide an opportunity to advance our understanding of stellar element synthesis and stellar evolution.

These measurements are being carried out with a Silicon Detector Array (SIDAR), and we will soon begin measurements using the Daresbury Recoil Separator, a 90-ton, 13-meter mass separator coupled to a number of sophisticated detector systems. We are incorporating our nuclear physics measurements into state-of-the-art computer stellar models to help interpret the new generation of astrophysical observations (e.g., from the Hubble Space Telescope and Compton Gamma Ray Observatory) and to guide both future stellar observations and future nuclear measurements.

More details of our program are given in an articles describing our recent accomplishments and a program overview. The astrophysical implications of one of our measurements is described in this press release prepared for the American Astronomical Society. The utilization of radioactive ion beams for nuclear astrophysics studies is discussed in detail in the review article "Nuclear Astrophysics Measurements with Radioactive Beams", M.S. Smith & K.E. Rehm, Ann. Rev. Nucl. Part. Sci. 51, 91 (2001).

Recent Measurements

We have measured the following reactions at HRIBF to better understand stellar explosions such as novae, X-ray bursts, and supernovae:

¹⁷F(p,p)¹⁷F to determine the ¹⁷F(p,gamma)¹⁸Ne reaction rate

D.W. Bardayan et al., Phys. Rev. C62 (2000) 055804       Abstract       Article


D.W. Bardayan et al., Phys. Rev. Lett. 83 (1999) 45      Abstract       Article


Physical Review Focus Article, July 1999                                Article

¹⁷F(p,alpha)¹⁴O, ¹⁷F(p,p)¹⁷F, and ¹⁷F(p,p')¹⁷F to determine the ¹⁴O(alpha,p)¹⁷F reaction rate

J.C. Blackmon et al., in preparation (2003)


J.C. Blackmon et al., Nucl. Phys. A718 (2003) 127        Abstract       Article


J.C. Blackmon et al., Nucl. Phys. A688 (2001) 142        Abstract       Article


R. Brummitt et al., Bull. American Phys. Soc. (2001)     Abstract

¹⁸F(p,p)¹⁸F to determine the ¹⁸F(p,gamma)¹⁹Ne and ¹⁸F(p,alpha)¹⁵O reaction rates

D.W. Bardayan et al., in preparation (2003)


D.W. Bardayan et al., Phys. Rev. C62 (2000) 042802(R)    Abstract       Article

¹⁸F(p,alpha)¹⁵O to determine this reaction rate directly

D.W. Bardayan et al., Phys. Rev. Lett. 89 (2002) 262501  Abstract       Article


D.W. Bardayan et al., Nucl. Phys. A718 (2003) 590        Abstract       Article


D.W. Bardayan et al., Phys. Rev. C63 (2001) 065802       Abstract       Article


D.W. Bardayan et al., Nucl. Phys. A688 (2001) 475        Abstract       Article

²⁸Si(p,t)²⁶Si to determine the ²⁵Al(p,gamma)²⁶Si reaction rate

D.W. Bardayan et al., Nuc. Phys. A718 (2003) 505         Abstract       Article


D.W. Bardayan et al., Phys. Rev. C65 (2002) 032801       Abstract       Article

¹⁸F(d,p)¹⁹F to determine the ¹⁸F(p,gamma)¹⁹Ne and ¹⁸F(p,alpha)¹⁵O reaction rates

R.L. Kozub et al., in preparation (2003)


R.L Kozub et al., Bull. American Phys. Soc. (2003)      Abstract

¹²⁴Sn(d,p)¹²⁵Sn to determine the ¹²⁴Sn(n,gamma)¹²⁵Sn reaction rate
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R.L. Kozub et al., in preparation (2003)
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¹⁷F(¹⁴N,¹³C)¹⁸Ne* to determine the direct capture ¹⁷F(p,gamma)¹⁸Ne reaction rate

J.C. Blackmon et al., in preparation (2003)


J.C. Blackmon et al., Nucl. Phys. A718 (2003) 587        Abstract       Article

⁸²Ge(d,p)⁸³Ge to determine the level structure of ⁸³Ge and the ⁸²Ge(n,gamma)⁸³Ge reaction rate

J.L. Thomas et al., in preparation (2003)


J.L. Thomas et al.,Bull. American Phys. Soc. (2003)      Abstract

Planned Experiments

A number of nuclear astrophysics experiments with radioactive ion beams have been approved or are planned for the near future:

¹⁷F(p,gamma)¹⁸Ne
⁷Be(p,gamma)⁸B
⁷Be(p,p)⁷Be
¹⁸F(p,alpha)¹⁵O
¹³²Sn(d,p)¹³³Sn

Further Information

Recent Accomplishments in Nuclear Astrophysics with Radioactive Ion Beams at HRIBF

Press Release for the 201 Meeting of the American Astronomical Society Meeting (Jan. 2003)

Overview of Experimental Nuclear Astrophysics Research Program at HRIBF

Review Article: "Nuclear Astrophysics Experiments with Radioactive Ion Beams", M.S. Smith & K.E. Rehm, Ann. Rev. Nucl. Part. Sci. 51, 91 (2001).

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