The fission cross section of 235U from 0,01 eV to 0,1 eV and its absolute value at 0,0253 eV

A.J. Deruytter

Research outputpeer-review


The absolute fission cross section of 235U at the reference neutron velocity of 2200 m/sec was measured. The counting rate of a 10B fission chamber was compared with that of a ionization chamber by alternate measurements in a neutron beam emergent from the thermal column of BRI. The energy selection was done with a slow chopper previously calibrated with respect to the sharp breaks of σ, for α Fe, Be, Bi, Al, C (graphite). The efficiency of the 10B chamber was compared to the well-known absorption cross section of 197Au by activation measurements with a (β-γ) coincidence technique. The thickness of the layer was determined by comparison with α-standards of the same isotopic composition, and controlled by a massapectrometric method. Our determination yields:
σf0= (587 ± 6) barns. Some information is also obtained about the nearby negative energy levels.
Original languageEnglish
PublisherSCK CEN
Number of pages15
StatePublished - Jan 1961
Externally publishedYes

Publication series

NameSCK CEN Reports
PublisherSCK CEN

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