INVESTIGATION OF (n,2n) REACTIONS LEADING TO THE FORMATION OF ISOMERS

Journal Article · Wed Mar 01 04:00:00 EST 1961 · Zhur. Eksptl'. i Teoret. Fiz.

OSTI ID:4060968

Glagolev, V L; Yampol'skii, P A

Data are presented on the cross sections for (n, 2n) reactions involving 14.7-Mev neutrons and leading to the formation of the isomers Y/sup 8//sup 8//sup m/( sigma m> 0.4 barns), Nb/sup 9//sup 2//sup g/ ( sigma =0 .53 plus or minus 0.06 barns), Pb/sup 2//sup 0//sup 7//sup m/( sigma m = 1.7 plus or minus 0.3 barns), Bi/sup 2//sup 0//sup 8/ /sup m/( sigma m = 0.66 plus or minus 0.12 barns). The cross section for the reaction with lead is evaluated in the assumption that the isomer is produced only in the reaction Pb/sup 2//sup 0//sup 8/(n, 2n) Pb/sup 2//sup 0//sup 7//sup m/. The correspondi ng value is compared with that computed by strong interaction theory and under the assumption of a two- stage mechanism of neutron evaporation in the (n,2n) reaction. The Pb/sup 2//sup 0//sup 7/ level scheme which agrees with the shell model is employed in the calculations. The relative probabilities for various types of transitions were estimated from the relation between the lifetime of a nucleus in the excited state and the transition energy. The results of the measurements and the calculations are in good agreement. The radiation characteristics of the following isomers are reported: Nb/sup 9//sup 2//sup g/ (T/sub 1//sub ///sub 2/ = 10.0 plus or minus 0.3 d, E/sub y/ = 0.94 plus or minus 0.01 Mev), Bi/sup 2// sup 0//sup 8//sup m/(T/sub 1//sub ///sub 2/, =2.6 plus or minus 0.1 msec, E/sub y/ = 0.50 plus or minus 0.02 Mev, E/sub y/ = 0.88 plus or minus 0.02 Mev) and Na/sup 2//sup 4//sup m/(T/sub 1//sub ///sub 2/ = 18.3 plus or minus 0.6 msec). (auth)

• Research Organization: Inst. of Chemical Physics, Academy of Sciences, USSR
• NSA Number: NSA-15-020213
• OSTI ID: 4060968
• Journal Information: Zhur. Eksptl'. i Teoret. Fiz., Journal Name: Zhur. Eksptl'. i Teoret. Fiz. Vol. Vol: 40
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

BISMUTH 208
CROSS SECTIONS
ENERGY
ENERGY LEVELS
ENERGY RANGE
EVAPORATION
EXCITATION
FAST NEUTRONS
GAMMA RADIATION
HALF-LIFE
INTERACTIONS
ISOMERS
LEAD 207
LEAD 208
MEASURED VALUES
NIOBIUM 92
NUCLEAR MODELS
NUCLEAR REACTIONS
NUMERICALS
PHYSICS
SHELL MODELS
SODIUM 24
TRANSIENTS
YTTRIUM 88