High-Resolution {alpha} and Electron Spectroscopy of {sup 249}{sub 98}Cf

Journal Article · Mon Apr 13 00:00:00 EDT 2015 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.91.044310· OSTI ID:1251623

Ahmad, I.; Greene, J. P.; Kondev, F. G.; Zhu, S.

alpha-particle spectra of Cf-249 have been measured with a double-focusing magnetic spectrometer and with passivated implanted planar silicon (PIPS) detectors. The conversion-electron spectra of Cf-249 have been measured with a cooled Si(Li) detector and with a room-temperature PIPS detector. Precise energies of a groups in the decay of Cf-249 have been measured with respect to the known energy of Cf-250. In addition, alpha-electron, alpha-gamma, and gamma-gamma coincidence measurements were also performed to determine the spin-parity of the previously known 643.64-keV level. From electron intensities, conversion coefficients of transitions in the daughter Cm-245 have been determined. The measured L-3 conversion coefficients of the 333.4- and 388.2-keV transitions are found to be in agreement with the theoretical conversion coefficients for pure E1 multipolarity. On the other hand, the K, L-1 + L-2, M, and N conversion coefficients are approximately twice the theoretical values for pure E1 transitions. These measurements indicate anomalous E1 conversion coefficients for the 333.4- and 388.2-keV transitions, as has been pointed out in earlier measurements. The measured conversion coefficient of the 255.5-keV transition gives an M1 multipolarity for this transition which establishes a spin-parity of 7/2(-) and the 7/2(-)[743] single-particle assignment to the 643.64-keV level.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science - Office of Nuclear Physics
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1251623
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 91, Issue 4; ISSN 0556-2813
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English