Nuclear Spectroscopy Research

Our nuclear spectroscopy research program involves accelerator-based experiments carried out at a variety of facilities: Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory, and TRIUMF.  In recent years, our spectroscopy experiments have used large arrays of high-resolution Ge detectors, including Gammasphere, an array of 110 detectors shown below left, and the 8-pi spectrometer, and array of 20 detectors shown below right.

Our goals in these experiments have been to make high-resolution studies of the gamma rays emitted in the radioactive decays of various nuclei in order to gain a better understanding of their structure.  In certain cases we have been able to use the decay information to obtain astrophysical information, in particular galactic lifetimes of nuclear species that are present in cosmic rays.  The spectroscopic information from the multi-detector arrays has included data on the angular correlations of the gamma rays, which has enabled us to deduce spin-parity assignments and the multipolarity of the gamma transitions.  Our collaborators in these experiments are Professor John Wood of Georgia Tech and Professor Eric Norman of the University of California at Berkeley.  The research has been funded by the U.S. Department of Energy.

Here are some representative publications from these experiments (for a complete list click here):

"Cosmic-Ray History Derived from the ⁵⁴Mn, ⁵⁶Ni and ¹⁴⁴Pm Chronometers," K. Zaerpoor, Y. D. Chan, D. E. DiGregorio, M. R. Dragowsky, M. M. Hindi, M. C. P. Isaac, K. S. Krane, R.-M. Larimer, A. O. Macchiavelli, R. W. Macleod, P. Miocinovic, E. B. Norman, and S. J. Robinson, Nucl. Phys. A654, 916c (1999).

“N = 90 Region: The Decay of ¹⁵⁴Eu to ¹⁵⁴Gd,” W. D. Kulp, J. L. Wood, K. S. Krane, J. Loats, P. Schmelzenbach, C. J. Stapels, R.-M. Larimer, and E. B. Norman, Phys. Rev. C 69, 064309 (2004).

“Identification of a Pairing Isomeric Band in ¹⁵²Sm,” W. D. Kulp, J. L. Wood, P. E. Garrett, J. M. Allmond, D. Cline, A. B. Hayes, H. Hua, K. S. Krane, R.-M. Larimer, J. Loats, E. B. Norman, P. Schmelzenbach, C. J. Stapels, R. Teng, and C. Y. Wu, Phys. Rev. C 71, 041303 (2005).

“Precision Test of the Rotor Model from Band Mixing in ¹⁶⁶Er,” W. D. Kulp. J. M. Almond, P. Hatcher, J. L. Wood, J. Loats, P. Schmelzenbach, C. J. Stapels, K. S. Krane, R.-M. Larimer, and E. B. Norman, Phys. Rev. C. 73, 014308 (2006).

“N = 90 Region: The Decays of ¹⁵²Eu^m,g to ¹⁵²Sm,” W. D. Kulp, J. L. Wood, J. M. Allmond, J. Eimer, D. Furse, K. S. Krane, J. Loats, P. Schmelzenbach, C. J. Stapels, R.-M. Larimer, E. B. Norman, and A. Piechaczek, Phys. Rev, C 76, 034319 (2007).

Here is a list of graduate theses of students who have worked in our group:

“A Study of the Decay ¹⁸⁴Au - ¹⁸⁴Pt by Means of Gamma and Electron Spectroscopy and Low Temperature Nuclear Orientation,” Yue-shu Xu (Ph.D., 1992)

“Nuclear Structure Studies of ^187,189Ir Via Low Temperature Nuclear Orientation and Coincidence Spectroscopy,” Mark A. Gummin (Ph.D., 1992)

“Relative Lifetime Measurements of ¹⁹²Hg and ¹⁹³Hg Superdeformed Bands.” Brian C. Busse (Ph.D., 1997)

“⁵⁴Mn, ⁵⁶Ni, and ¹⁴⁴Pm as Cosmic-Ray Chronometers,” Koorosh Zaerpoor (Ph.D., 1998)

“Sudbury Neutrino Observatory Energy Calibration Using Gamma-Ray Sources,” Michael R. Dragowsky (Ph.D., 1999)

“The Study of ¹⁵⁰Sm through the Decay of ¹⁵⁰Pm, ^150mEu and ^150gEu,” Paul D. Schmelzenbach (Ph.D., 2003)

“Level Structure of ¹⁵²Gd Populated in ¹⁵²Tb Beta Decay,” C. J. Stapels (Ph.D.,  2004)

“Angular Correlation Measurements From the Beta Decay of ^166mHo and ¹⁶⁶Tm and the Properties of the Gamma Vibrational Band in ¹⁶⁶Er,” Jeffrey T. Loats (Ph. D., 2004)