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The University of Tennessee

Department of Physics and Astronomy

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    Contact Information


    Prof. Carrol Bingham
    607 SERF Building
    Knoxville, TN 37996
    Phone: 865-974-7802


    Dr. Robert Grzywacz
    613 SERF Building

    Knoxville, TN  37996
    Phone: (865) 974-2918


Decay Spectroscopy

See also :  Experimental Nuclear Astrophysics : High Spin Gamma Ray Spectroscopy :

Decay spectroscopy is a broad brush to describe a variety of techniques which we use to determine the decay properties of radioactive nuclei, by observing the particles emitted from the nucleus when it changes species.

Decay experiments are at the forefront of exploration at the limits of nuclear stability. Once the existence of an isotope has been verified the next critical piece of information sought is its decay mechanism. Modern experimental setups can possess great sensitivity measuring intrinsic physical parameters such as particle decay energies, half-lives and branching ratios as well as identifying first excited states and isomeric decays from a comparatively small number of events against even large backgrounds. For nuclei which can be produced in greater abundances complete decay studies can be performed where detailed spectroscopic information such as β-strength functions or nuclear moments and spins can be extracted.

Though tailored to the particular nuclei of interest in the experiment a study utilising decay spectroscopy techniques will have some common traits ( and indeed traits similar to other nuclear physics experiments). The isotope to be studied must be produced, for example in a Heavy Ion Fusion Evaporation or Fragmentation Reaction. Once created the nuclei must be selected, transported and implanted into a detection system. This may be accomplished using a Recoil Separator device such as the RMS. The implantation detector will depend on the study undertaken but common detectors are low temperature segmented Silicon and cryogenically cooled segmented Hyperpure Germanium detectors. Once implanted the nucleus is observed until its decay when its characteristic radiation is measured and its physical properties calculated. During these experiments the number of implanted nuclei can vary widely for example ranging from 5Hz to 5kHz.

The UT group has been at the forefront in developing sophisticated digital electronics and associated software to analyse and sift through the data obtained in these experiments.

 For examples of our decay spectroscopy studies see:

  • Charged Particle Emission Above 100Sn (link under construction)

  • β- Studies Around Doubly-Magic 78Ni (link under construction)

  • Decay Spectroscopy With Digital Signal Processing (link under construction)

4 Silicon detectors in a box configuration.

A stack of 3 Si detectors used at the NSCL

A DSSD attached to a vacuum backplate used at the RMS.

A Double Sided Germanium Strip Detector made by PHDs Co

A DGF4C card