Coincident electrofission of /sup 238/U at qroughly-equal0. 26, 0. 40, and 0. 55 fm/sup -1/

Journal Article · Wed Oct 01 04:00:00 EDT 1986 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.34.1375· OSTI ID:5211388

Griffioen, K A; Countryman, P J; Knoepfle, K T; Van Bibber, K; Yearian, M R; Woodworth, J G; Rowley, D; Calarco, J R

We have measured the coincidence cross sections /sup 238/U(e,e'f) at three values of momentum transfer (qroughly-equal0.26, 0.40, and 0.55 fm/sup -1/) over the range from 5 to 23 MeV in excitation energy; these values of q correspond approximately to the first maxima of the electric dipole, quadrupole/monopole, and octupole form factors, respectively. The angular distribution of fission fragments is peaked along the direction of q near fission threshold, indicating the dominance of K -- 0 states, but becomes isotropic above 10 MeV. We have integrated our cross sections over fission angle and compared them to recent calculations of multipole strength derived in the quasiparticle random phase approximation. Using model-dependent form factors generated from the Tassie model and the quasiparticle random phase approximation, we have extracted strength functions for the lowest electric multipoles. The deduced E1 strength agrees well with photofission results for reasonable choices of the model form factors. The E2/E0 distribution displays resonant structures at 10 and 13 MeV which agree in position with the collective E2 and E0 strength, respectively, predicted in the quasiparticle random phase approximation. If we make such an assignment for the multipolarity of these two structures, the observed E0 strength agrees with the theoretical prediction, whereas the E2 strength is low by a factor of 2-3. Higher order multipoles also contribute substantially to the cross section at our highest value of q.

• Research Organization: Department of Physics and High Energy Physics Laboratory, Stanford University, Stanford, California 94305
• OSTI ID: 5211388
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 34:4; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

652026* -- Nuclear Properties & Reactions
A=220 & above
Experimental-- Spontaneous & Induced Fission-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
CHARGED-PARTICLE REACTIONS
COINCIDENCE SPECTROMETRY
CROSS SECTIONS
DETECTION
DISTRIBUTION
E1-TRANSITIONS
E2-TRANSITIONS
ELECTROFISSION
ELECTRON REACTIONS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EQUATIONS
FISSION
FISSION FRAGMENT DETECTION
FORM FACTORS
GIANT RESONANCE
LEPTON REACTIONS
MEV RANGE
MEV RANGE 01-10
MEV RANGE 10-100
MOMENTUM TRANSFER
MULTIPOLARITY
MULTIPOLE TRANSITIONS
NUCLEAR REACTIONS
PARTICLE PROPERTIES
QUASI PARTICLES
RADIATION DETECTION
RANDOM PHASE APPROXIMATION
RESONANCE
SUM RULES
TARGETS
URANIUM 238 TARGET