THE ACTUAL SITUATION IN THE FIELD OF NUCLEAR REACTIONS AT INTERMEDIATE ENERGY (in Italian)
A brief discussion of the new data obtained on nuclear reactions st energies from a few Mev to several tens of Mev is presented. The mechanisms of direct effects are discussed. (J.S.R.) 236lO The total neutron cross section of B/sup 10/ was measured at neutron energies between 0.00291 ev and 0.1 ev with the Columbia Uilversity crystal spectrometer. The B/sup 10/absorption cross section was obtained by subtracting the relatively small, known, scattering cross section from the measured total cross section. Two samples enriched to 92.84 plus or minus 0.06 at.% and 99.88 plus or minus 0.01 at.% B/sup 10/ were used for these measurements. The B/sup 10/ absorption cross section obthined with the 92.84% B/sup 10/ sample followed the relation E/sup 1/2/ sigma /sub a/ = 612.3 plus or minus 2.4 barns ev/sup 1/2/ and yielded a value of 3 849 plus or minus 15 barns at 0.0253 ev. For the 99.88% B/sup 10/ sample, the B/sup 10/ absorption cross section obeyed the relation E/sup 1/2/ sigma /sub a/ = 608.9 plus or minus 2.3 barns ev/sup 1/2/ and gave a value of 3828 plus or minus 15 barns at 0.0253 ev. A sample of Argonne-Brookhaven standard normal boron, 19.8 plus or minus 0.1% B/sup 10/, was measured simultaneously. The resulting absorption cross section for normal boron was sigma /sub a/(0.0263 ev) = 764 plus or minus 3 barns and obeyed the relation E/sup 1/2/ sigma /sub a/= 121.5 plus or minus 0.5 barns ev/sup 1/2/. The average of the resul ts for the two enriched samples yields sigma /sub a/ (B/sup 10/) = 3838 plus or minus 11 barns at 0.0253 ev and E/sup 1/2/ sigma /sub a/(B/sup 10/ = 610.5 plus or minus 1.7 barus ev/ sup 1/2/. The ratio of the above values of the absorption cross sections for B/sup 10/ and normal boron yields a value of 19.9 plus or minus 0.1% B/sup 10/ for the normal sample which is in good agreement with mass spectrometer determinations. (auth)
- Research Organization:
- Centro Informazioni Studi Esperienze, Milan
- NSA Number:
- NSA-14-023609
- OSTI ID:
- 4156046
- Journal Information:
- Nuovo Cimento (Italy) Divided into Nuovo Cimento A and Nuovo Cimento B, Journal Name: Nuovo Cimento (Italy) Divided into Nuovo Cimento A and Nuovo Cimento B Vol. Vol: (10) 16, Suppl. No. 1; ISSN NUCIA
- Country of Publication:
- Country unknown/Code not available
- Language:
- Italian
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