1 - IAEA Nuclear Data Services

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Numerical values of these fit curves describing the
relative cross-sections are given in tablen in 0.1 ñéV
steps.
Also shown in the figures are the [1] excitation
functions reported by Strohal et al., Csikai [21 ^Q^
Bormann and Riehle [3]. Our data,as well as Bormanns
definitely show that the large fluctuations found by
Strohal and Csikai do not exist and are probably due
to systematic errors. Only in the two reactions
24
Mg (n,p) and Al (n,a) some structure (however
completely different from Strohal's results) seems to
be definitely present-For all reactions involving
nuclei heavier than aluminium no fine structure is
detectable within the experimentel errors of about 1 %.
In addition ratios of the cross-sections to the
27
AI (n,a)
cross-section were determined for 8, of the reactions
investigated at 14.7 MeV.
An accuracy of 2 - 3 % (including all systematic errors)
was obtained by means of.careful efficiency calibrations
of the well crystal used. The experimentally
determined ratios as well as the absolute cross-sections
obtained with a value of 111.5 mb for the ^Al (n,a)
cross-section are given in table ICI. The value of
111.5 mb was obtained,as we weighted average of all
previously reported measurements by Nagel. [5].
Literature
[1 1 P. Strohal et.al. Phys. Letters 6 (1963) 205
[2] J. Csikai Proc. Int. Conf. on the Study of Nuclear
Structure with Neutrons Antwerpen 1965
[3] M. Bormann and I. Riehle Z. f. Physik 207, 64 (1967)
[4] J..M. Ferguson and I.C. Albergotti N.P. A98 (1967) 65
[5] W. Nagel, Thesis University of Amsterdam (1966)