The electromagnetic excitation of [sup 11]Li

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7112399

Sackett, D W

A kinematically complete measurement of the Coulomb dissociation of a 28 MeV/nucleon beam of [sup 11]Li into [sup 9]Li and two neutrons by a Pb target has been performed. From the energies and angles of the emitted neutrons and of [sup 9]Li, the excitation energy was constructed. The dipole strength function dB(E1)/dE and the photonuclear spectrum, [sigma][sub E1](E), were determined from the Coulomb dissociation spectrum. The photonuclear spectrum [sigma][sub E1](E) has a peak at E = 1.0 MeV and a width [Sigma] = 0.8 MeV. These parameters are consist with the picture of a soft dipole resonance but a significant post-breakup Coulomb acceleration of [sup 9]Li suggests a direct breakup. The complete kinematical measurement also allowed neutron and [sup 9]Li momentum distributions to be constructed in the rest frame of the [sup 11]Li. The momentum distributions were fitted with Gaussian functions, yielding width parameters of [sigma][sub 9] = 18 [+-] 4 MeV/c and [sigma][sub n] = 13 [+-] 3 MeV/c. A more general feature of the breakup mechanism of [sup 11]Li could be deduced from these measurements. It was found that the [sup 9]Li and neutron momentum distributions, and the neutron-neutron relative momentum distributions, could be reproduced if the [sup 11]Li excitation energy was partitioned between the [sup 9]Li and the neutrons by a 3-body phase space distribution. This indicates there is no directional correlation between the halo neutrons.

• Research Organization: Michigan State Univ., East Lansing, MI (United States)
• OSTI ID: 7112399
• Country of Publication: United States
• Language: English

Related Subjects

663220 -- Electromagnetic Transitions-- (1992-)
663450* -- Heavy-Ion-Induced Reactions & Scattering-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALI METAL ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHARGED-PARTICLE REACTIONS
COULOMB EXCITATION
E1-TRANSITIONS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EXCITATION
FUNCTIONS
HEAVY ION REACTIONS
ISOTOPES
LIGHT NUCLEI
LITHIUM 11 REACTIONS
LITHIUM 9
LITHIUM ISOTOPES
MEV RANGE
MEV RANGE 10-100
MILLISEC LIVING RADIOISOTOPES
MULTIPOLE TRANSITIONS
NUCLEAR REACTIONS
NUCLEI
ODD-EVEN NUCLEI
PHOTONUCLEAR REACTIONS
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
STRENGTH FUNCTIONS