1 - IAEA Nuclear Data Services

- 1-4-0 -
= 100 meV below a = 0.6 and with = 27 meV
for a-value s higher than 1.0 i"9l.
?40
Subthreshold Fission Cross Section of Pu [10]
The subthreshold neutron induced fission cross section
24-0
of Pu has been measured with the fission neutron
detector in the energy range between 200 eV and 9 keV.
The resonance parameters have been determined with
an area analysis program. The fission spectrum obtained
shows a periodical appearance of clusters of resonances
with particularly high fission widths (Fig. 6). This
result is of special interest in relation to the theory
of Strutinsky who introduces shell effects into
nuclear deformation energies (Nucí. Phys. A95 (1967)
420-4-42).
235
Fission Cross Section of U
The measurement of this fission cross section is
being prepared with a spark chamber as fragmentand
the liquid scintillator as neutron-detector.
The spark chamber detector for fission fragment detection
of highly a-active fissile isotopes consists
of six wire-to-plate chambers (20 x 20 cm ). Nitrogen
circulates at a pressure of 250 Torr.
.^-Measurement and Determination of Neutron Multicrplicities
The mechanical construction of a large liquid scintillator
tank is ready. The realisation of a heavy
shield for this detector is continuing.
235
Normalization of Relative "^U Fission Cross-Sections
in the Resonance Region
A.J. Deruytter (CBNM), C. Vagemans*
These measurements are carried out at the CBNM linac
by a joint CBNM-SCK-team with the view to extend the
x Belgian research fellow NFVO (University of Gent)