Threshold photoneutron angular distribution and polarization studies of nuclei

Conference · Tue Jan 01 04:00:00 EST 1980

OSTI ID:6438413

Holt, R J

The photoneutron method was applied to the study of: (1) deuteron photodisintegration; (2) giant magnetic dipole resonances in heavy nuclei; (3) mechanism of radiative capture in light nuclei; and (4) isospin splitting of the giant dipole resonance in /sup 60/Ni. These studies were performed with the pulsed bremsstrahlung beam and high-resolution spectrometer available at the Argonne high-current electron linac. A threshold photoneutron polarization method was developed in order to search for the giant M1 resonance in heavy nuclei. A surprisingly small amount of M1 strength was found in /sup 208/Pb. Furthermore, the M1 strength for the 5.08-MeV excitation in /sup 17/O, the best example of a single-particle M1 resonance in nuclei, was found to be strongly quenched. In addition, the /sup 17/O(..gamma..,n/sub 0/)/sup 16/O reaction was found to provide an ideal example of the Lane-Lynn theory of radiative capture. The interplay among the three components of the theory, internal, channel and potential capture, were evident from the data. An electron beam transport system was developed which allows the bremsstrahlung to impinge on the photoneutron target on an axis perpendicular to the usual reaction plane. This system provides an accurate method for the measurement of relative angular distributions in (..gamma..,n) reactions. This system was applied to a high-accuracy measurement of the relative angular distribution for the D(..gamma..,n)H reaction. The question of isospin-splitting of the giant dipole resonance in /sup 60/Ni was studied by using the unique pico-pulse from the accelerator and the newly installed 25-m, neutron flight paths. The results provide clear evidence for the effect of isospin splitting.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6438413
• Report Number(s): CONF-801111-48; ON: DE81023724
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYONS
BETA DECAY RADIOISOTOPES
CROSS SECTIONS
DATA
DISTRIBUTION
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTARY PARTICLES
ELEMENTS
ENERGY LEVELS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FERMIONS
GIANT RESONANCE
HADRONS
HEAVY NUCLEI
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEAD 208
LEAD 208 TARGET
LEAD ISOTOPES
LIGHT NUCLEI
NEUTRONS
NICKEL 60
NICKEL 60 TARGET
NICKEL ISOTOPES
NONMETALS
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
NUMERICAL DATA
OXYGEN 17
OXYGEN 17 TARGET
OXYGEN ISOTOPES
PHOTONEUTRONS
PHOTONUCLEAR REACTIONS
PHOTONUCLEONS
RADIOISOTOPES
RESONANCE
SECONDS LIVING RADIOISOTOPES
STABLE ISOTOPES
TARGETS
YEARS LIVING RADIOISOTOPES