1 - IAEA Nuclear Data Services

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5.3. Determination of Nuclear Constants
5.3.1. The Fluorescence Yield of Cr
W. Bambynek
The remeasurement of the fluorescence yield of Cr
using the ^nn-decay and several independent counting
methods was completed. The result (0.2793) is
accurate to within a few tenths of a percent and
shows definitely that the values, at present used,
are about 20% lower than the real ones. Fluorescence
65
yield determinations have been started on ^Zn. The
prepared evaporated sources show promising properties
and first measurements give very satisfactory results
(Wk = 0.433). Measurements on Y are under preparation
T30],[31].
5.3.2. Decay Scheme of 60 Co
H. Hansen, A. Spernol
In the presently accepted decay scheme of Co a level
of 2.16 MeV of the daughter nucleus Ni predicted by
the theory, is missing. A p-spectrometer investigation
showed that this level is populated by about 0.15% of
the decays. The subsequent Y-radiation of 0.823 MeV
was also detected in long term (10 days) Ge(Li)-measurements
with about the same intensity. The other
low intensity p-decays were also accurately determined.
Some theoretical conclusions could be drawn from this
new experimental result [32].
5-3.3. Decay of 137 Cs
H. Hansen, G. Lowenthal + , A. Spernol, W. van der Eijk,
R. Vaninbroukx
The decay scheme of -^'Cs was redetermined using as
many as possible methods. The (p+e)/Y ratio has been
determined by 4TT-, liquid scintillation and ^-spectrometer
measurements to 1.288 _+ 0.2%, the e/Y ratio by
Guest from A.A.E.C,