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Etude de quelques reactions nucleaires induites par les neutrons rapides de pile

Application au dosage radiochimique, plus specialement du silicium

Journal of Radioanalytical and Nuclear Chemistry
Authors:
W. Haerdi
and
R. Daniel

Abstract  

In the first part, the fast-neutron flux available in reactor cores was utilized to define experimentally the sensitivity for the determination of 12 different elements, based on fast-neutron nuclear reactions. The fluxes available with our AGN-201 P reactor are in the range of 109–1010 n·cm−2·sec−1 in the 1–4 MeV region. A good sensitivity was obtained for27Al,52Cr,56Fe,28Si,23Na [by (n, p) reaction],27Al,31P,89Y [by (n, α) reaction] and197Au,183W,89Y [by (n, n′) reaction]; the elements Cl, Ca, Pb failed to give reactions. In the second part, a non-destructive method for the determination of silicium based on the reaction28Si(n, p)28Al is proposed. The limit of determination is about 0.6 mg for a neutron flux of 109 n·cm−2·sec−1. As an example, Si in dimethylpolysilane was determined.

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Abstract  

In this paper, six methods of preconcentration on ion exchange or chelating filters and resins for neutron activation with X-ray and gamma spectrometry are described. These techniques are applied to the determination of trace elements in natural waters. The analysis of water samples from the lake of Geneva by these different methods gave results in good agreement among themselves and also when compared with those obtained by other techniques, with a very reasonable blank and good sensitivity for most determined elements.

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Abstract  

A non-destructive method for the determination of hafnium in zirconium and various alloys, based on the formation of178mHf and179mHf, is proposed. For a neutron flux of 109 n th ·cm−2·sec−1, the limit of determination is about 0.5 μg. This limit can fall to 50 ng with the multiple irradiation runs system (ten runs at 92-second cycles). The simple determination is complete within 15 minutes, whereas the multiple irradiation runs method requires about 15 minutes longer time.

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