High energy gamma rays from complex particle collisions
Abstract
High energy (GAMMA)-rays (E/sub (GAMMA)/ approx. 10 to 30 MeV), from the decay of Gaint Dipole Resonance built on excited nuclear states (e.s.-GDRs) are a common feature of all energetic nuclear collisions. Current results indicate that for bombarding energies below 5 to 6 MeV per nucleon the statistical emission of high energy (GAMMA)-rays predominates in complex particle collisions. Statistical GDR properties have now been studied over a wide range of mass, energy and angular momentum. Recent results include: (1) in light compound nuclei considerably broadened e.s.-GDRs are observed, with strengths that indicate relatively pure compound nuclei isospin, (2) in medium mass nuclei (A approx. 60 to 80) e.s.-GDRs are found with substantially reduced strength (approx. 0.5 of the classical dipole sum rule) and (3) in rare-earth deformed nuclei a splitting of e.s.-GDRs is apparent, indicating the persistence of deformation at elevated temperature. At higher bombarding energies (6 to 9 MeV per nucleon) for (3)He and (4)He strong enhancements are seen for E/sub (GAMMA)/ approx. 15 MeV, due to nonstatistical effects.
- Publication:
-
Presented at the Capture Gamma-Ray Spectroscopy Conf
- Pub Date:
- 1984
- Bibcode:
- 1984cgrs.conf.....S
- Keywords:
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- Gamma Rays;
- Nuclear Physics;
- Nuclear Structure;
- Particle Collisions;
- Energy Levels;
- Excitation;
- Heavy Ions;
- Nuclear and High-Energy Physics