1 - IAEA Nuclear Data Services

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cross section of
240
Pu have been terminated. 264 resonances
between 20 eV and 5.7 keV have been analysed
with respect respect to F using the area analysis program of
Atta and Harvey.
Combining the results of this transmission measurement
with those of a capture experiment (see 2.7.1.),
a full set of resonance parameters (E , F and F^.)
for 32 resonances between 38 eV and 820 eV has been
determined. The first 100 resonances of the resolved
resonance range (20 eV - 1500 eV) have been used to
evaluate their statistical properties with the following
results:T8]r8a]
Mean level spacing: = 15.7 +. 0.8 eV
Mean reduced neutron width: = 1.54+0.22 meV 4
¿¿-wave strength function: S = (1.05 ± 0.16)-10
K.H. Bockhoff, G. Carraro, W. Kolar
This measurement was prepared, especially by testing
a Li-glass detector. At low neutron energies this
detector gives a 5 to 4 times higher response than
the B detector. The signal-to-background ratio was
the same in both cases up to energies of about 400 eV.
2.1.2. High Energy Range (En > 200 keV)
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K.H. Bockhoff
The experimental set-up, described in the previous
progress report, is now operating. The time of flight
spectra from water- or mercury-cooled targets showed
a structure, due to resonances of the stainless steel
canning material (besides the one from oxygen for
water-cooled ones). Air-cooled graphite targets produced
no structure up to 2 MeV but the neutron yield
was low. A tungsten target produced only a slight