137Ba double gamma decay measurement with GAMMASPHERE

E. Merchán, K. Moran, C. J. Lister, P. Chowdhury, E. A. McCutchan, J. P. Greene, S. Zhu, T. Lauritsen, M. P. Carpenter, R. Shearman

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


The study of the electromagnetic moments (EM), and decay probability, provides detailed information about nuclear wave functions. The well-know properties of EM interactions are good for extracting information about the motion of nucleons. Higher order EM processes always occur, but are usually too weak to be measured. In the case of a 0+ → 0+ transitions [1, 2], where a single gamma transition is forbidden, the simultaneous emission of two γ-rays has been studied. An interesting opportunity to further investigate 2-photon emission phenomena is by using a standard 137Cs source populating, via β-decay, the Jπ = 11/2- isomeric state at 662 keV in 137Ba. In this case, two photon process can have contributions from quadrupole-quadrupole or dipole-octupole multipolarities in direct competition with the high multipolarity M4 decay. Since the yield of the double gamma decay is around six orders of magnitude less than the first order transition, very good statistics are needed in order to observe the phenomena and great care must be taken to suppress the first-order decay. The Gammasphere array is ideal since its configuration allows a good coverage of the angular distribution and the Compton events can be suppressed. Nevertheless the process to understand and eliminate the Compton background is a challenge. Geant4 simulations were carried out to help understand and correct for those factors. Owned by the authors, published by EDP Sciences, 2015.

Original languageEnglish (US)
Title of host publicationCGS15 2014 - Capture GammaRay Spectroscopy and Related Topics
EditorsKai Zuber, Ronald Schwengner
PublisherEDP Sciences
ISBN (Electronic)9782759817948
StatePublished - May 28 2015
Externally publishedYes
Event15th International Symposium on Capture Gamma Ray Spectroscopy and Related Topics, CGS15 2014 - Dresden, Germany
Duration: Aug 25 2014Aug 29 2014

Publication series

NameEPJ Web of Conferences
ISSN (Print)2101-6275
ISSN (Electronic)2100-014X


Conference15th International Symposium on Capture Gamma Ray Spectroscopy and Related Topics, CGS15 2014

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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