1 - IAEA Nuclear Data Services

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Á. SOTTQSEZIONE DI FIRENZE DELL'ISTITUTO NAZIONALE DI FÍSICA
NUCLEARE - ISTITUTO DI FÍSICA DELL'UNIVERSITA', FIRENZB (ITALY)
.1. B and y spectroscopy
The Group for 13 and y spectroscopy has been studying the
decays of some nuclei with solid state detectors.
.2. Decay of Ba
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The relative gamma-ray intensities m the decay of Ba have
been determined by means of Germanium detectors. A reasonable
value of long ft of an EC second forbidden transition is obtain
ed. The experimental electromagnetic transition strengths con-
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necting 3 excited states and the ground state of Cs are found
to agree fairly well with the theoretical estimates of the liss-
linger-Sorensen model [l] .
.3. Decay of 176m Yb
The isomeric level (-T¿ =11.7 sec) of Yb [2], obtained by
bombarding an enriched sample of Yb isotope with 14 MeV
neutrons, has been studied. The energies of the single transi­
tions have been determined to a precision of about 0.3 KeV by
fixing the isomeric state at 1050.1+0.6 KeV. A study by means
of Germanium detectors andy-Ycoincidence measurements supplied
a good value of the total conversion coefficient of the isomeric
transition of 95.9 KeV, thus establishing the E1 nature of this
transition. Hence the value 8 for the spin and the parity of
the isomeric level is also established. The level, therefore,
must certainly be interpreted as due to the coupling, according
to the rules of Gallagher and Soloviev, of two neutrons in
Nilsson's orbits 7/2~[514-]and 9/2 + [624J.
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,4. Decay of Sm and the Pm levels
By means of a Germanium detector the y transitions among some
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levels of Pm. (populated in the decay of Sm) have been