ORNL

Measurements of Neutron-Induced Reactions

for Nuclear Astrophysics at ORELA
The synthesis of all heavy elements with A > 60 has been attributed primarily to neutron-capture processes. Advances in our understanding of these processes, and of the astrophysical sites where they occur -- such as red giants and possibly supernovae -- require advances in laboratory measurements of neutron-capture processes. The overwhelming majority of (n,gamma) cross section measurements, which comprise the crucial input for astrophysical models of heavy element nucleosynthesis, have been made at one facility: the Oak Ridge Electron Linear Accelerator (ORELA). Its long history in the field of (n,gamma) measurements, along with recent technical improvements and a new program of (n,alpha) measurements addressing p-process explosive nucleosynthesis, make ORELA uniquely suited to enable further advances in our understanding of heavy element nucleosynthesis.

A new White Paper - "Opportunities in Nuclear Astrophysics at the Oak Ridge Electron Linear Accelerator" - describes in detail both the recent work and future opportunities of nuclear astrophysics work at ORELA.


Opportunities in Nuclear Astrophysics at the Oak Ridge Electron Linear Accelerator

Overview of Measurements at ORELA

Abstracts of Completed Research Projects at ORELA

Recent Experiments

 147Sm(n,alpha)
Yu.M. Gledenov, P.E. Koehler, J. Andrzejewski, K.H. Guber, T. Rauscher
Phys. Rev. C62 (2000) 042801(R)

Abstract



88Sr(n,gamma)
P.E. Koehler, R.R. Winters, K.H. Guber, T. Rauscher, J. A. Harvey, S. Raman, R. R. Spencer, J. C. Blackmon, D. C. Larson, D. W. Bardayan, T. A. Lewis
Phys. Rev. C62 (2000) 055803

Abstract



137Ba(n,gamma)
P.E. Koehler, K.H. Guber, S. Raman, J.A. Harvey, N.W. Hill, J.C. Blackmon, D.W. Bardayan, D.C. Larson, T.A. Lewis, D. Pierce, M.S. Smith, R.R. Spencer, R.R. Winters
Bull. Am. Phys. Soc. 42 (1997) 1680; Phys. Rev. C57 (1998) R1558.

Abstract



116,120Sn(n,gamma)
P.E. Koehler, R.R. Spencer, K.H. Guber, J.A. Harvey, N.W. Hill, R.R. Winters
Bull. Am. Phys. Soc. 42 (1997) 983.

Abstract



142,144Nd(n,gamma)
K.H. Guber, R.R. Spencer, P.E. Koehler, R.R. Winters
Phys. Rev. Lett. 78 (1997) 2704.

Abstract



134,136Ba(n,gamma)
P.E. Koehler, R.R. Spencer, R.R. Winters, K.H. Guber, J.A. Harvey, N.W. Hill, M.S. Smith
Phys. Rev. C 54 (1996) 1463.

Abstract



7Li(n,gamma)
J.C. Blackmon, A.E. Champagne, J.K. Dickens, J.A. Harvey, M.A. Hofstee, S. Kopecky, D.C. Larson, D.C. Powell, S. Raman, M.S. Smith
Phys. Rev. C 54 (1996) 383.

Abstract



A BaF2 Detector System for (n,gamma) Cross Section Measurements at ORELA
K.H. Guber, R.R. Spencer, P.E. Koehler, R.R. Winters
Nucl. Phys. A621 (1997) C254.

Abstract





Research sponsored, in part, by the Oak Ridge National Laboratory, managed by UT-Battelle LLC for the U.S. Department of Energy under contract DE-AC05-00OR22725.

Any questions or comments should be directed to Paul Koehler at koehler@mail.phy.ornl.gov or to Michael Smith at msmith@mail.phy.ornl.gov

ORNL
Astrophysics Program 		Experimental
Nuclear Astrophysics 		Recent
Progress Report 		HRIBF ORELA Low Energy
Nuclear Physics

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Rev:  Wednesday, 01-Nov-2000