Photonuclear reactions in /sup 90/Zr
Photonuclear reactions in /sup 90/Zr were studied in the excitation region of the giant dipole resonance. Experimental results which include all the most important reaction channels consist of cross sections integrated over angles, and for photoprotons, of additional data on angular distributions. Photoproton cross sections were determined by a least-squares-fit analysis of proton spectra resulting from a series of irradiations with bremsstrahlung of different end-point energies. In addition to the ground state /sup 90/Zr(..gamma.., p/sub 0/)/sup 89/Y/sub g.s./, photoproton cross-section data for three groups of /sup 89/Y excited states are presented. Other results which consist of cross sections for reactions (..gamma.., p/sub 1/), (..gamma.., n/sub 1/), (..gamma.., 2n), (..gamma.., np), and (..gamma.., n) were obtained through different techniques based on the measurement of activation yields. It is shown that 70% of the total photoproton cross section is due to the transition to the ground, the 1.74 MeV, and possibly the 1.51 MeV states of /sup 89/Y. The photoneutron cross section is dominated by the contribution involving the first excited state and all those states of /sup 89/Zr which subsequently decay to it. Experimental data are interpreted in terms of isospin splitting of the giant dipole resonance. In the total photoproton cross section, apart from a broad resonance at 16 MeV similar to the dominant structure of the (..gamma.., n) reaction, an additional resonance of approximately the same magnitude appears at 20.5 MeV. The latter resonance is attributed to the T/sub >>/ part of the giant dipole resonance. Its integrated cross section of about 8% of the total photonuclear cross section accounts for the main part of the expected T/sub >/ strength. Neutron channels do not seem to contribute significantly to the decay of the T/sub >/ resonance. It is concluded from (..gamma.., np) and (..gamma.., 2n) reactions that the T/sub >/ resonance is superimposed on a T/sub
- Research Organization:
- J. Stefan Institute, University of Ljubljana, Ljubljana, Yugoslavia
- OSTI ID:
- 7354491
- Journal Information:
- Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 13:5; ISSN PRVCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
A=90-149
Experimental-- Nuclear Reactions & Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYONS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CROSS SECTIONS
DAYS LIVING RADIOISOTOPES
DIRECT REACTIONS
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTARY PARTICLES
ENERGY RANGE
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FERMIONS
GIANT RESONANCE
HADRONS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KNOCK-OUT REACTIONS
MEV RANGE
MEV RANGE 10-100
MINUTES LIVING RADIOISOTOPES
NEUTRONS
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
PHOTONEUTRONS
PHOTONUCLEAR REACTIONS
PHOTONUCLEONS
PHOTOPROTONS
PROTONS
RADIOISOTOPES
RESONANCE
SECONDS LIVING RADIOISOTOPES
STABLE ISOTOPES
TARGETS
YTTRIUM 88
YTTRIUM 89
YTTRIUM ISOTOPES
ZIRCONIUM 88
ZIRCONIUM 89
ZIRCONIUM 90 TARGET
ZIRCONIUM ISOTOPES