Partition of cross sections in asymmetric nucleus-nucleus reactions and the origin of fast alpha particles

Conference · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5559307

Siemssen, R H

To investigate the mechanism of asymmetric nucleus-nucleus reactions from the Coulomb barrier to intermediate energies the /sup 14/N + /sup 159/Tb reaction was studied at five bombarding energies between 8 and 23 MeV/u via particle-particle correlations (at selected energies) and particle KX-ray coincidences to identify the specific reaction channels. With the KX-ray method partial cross sections for projectile-like fragments (PLF) as a function of the atomic number (Z/sub res/) of the residual nucleus can be determined. The charge balance yields the ''missing charge'' dZ = Z/sub proj/ + Z/sub targ/ - Z/sub PLF/ - Z/sub TLF/ that indicates whether, in addition to the PLF, other charged particles are emitted. A large fraction of the inclusive cross sections is found to originate from such channels with two or more fragments in the exit channel, and this fraction increases as the PLF is further removed in mass from the incident projectile, and with increasing bombarding energy. From the particle-particle correlation studies it is found that sequential decays of PLF's are dominant. ''Non-sequential'' processes, if present, are associated with inelastic reactions involving excitations of both projectile and target. The bulk of the large alpha-particle cross section at small angles is found to be associated with channels in which, in addition to the alpha particle, only nucleons and other alpha particles are emitted. From ..gamma..-ray multiplicity measurements and from the broad distribution of the strength with Z/sub res/ it is concluded that these alpha particles originate from inelastic (damped) processes. 27 refs., 10 figs.

• Research Organization: Argonne National Lab., IL (USA); Rijksuniversiteit Groningen (Netherlands). Kernfysisch Versneller Inst.
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5559307
• Report Number(s): CONF-8505172-2; ON: DE85014989
• Country of Publication: United States
• Language: English

Related Subjects

651825* -- Nuclear Properties & Reactions
A=150-189
Experimental-- Nuclear Reactions & Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
ALPHA PARTICLES
BERYLLIUM 9
BERYLLIUM ISOTOPES
BORON 11
BORON ISOTOPES
CARBON 13
CARBON ISOTOPES
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
COINCIDENCE METHODS
COUNTING TECHNIQUES
CROSS SECTIONS
DATA
ELECTROMAGNETIC RADIATION
ENERGY RANGE
ENERGY SPECTRA
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
GAMMA RADIATION
HEAVY ION REACTIONS
INFORMATION
IONIZING RADIATIONS
ISOTOPES
LIGHT NUCLEI
LITHIUM 7
LITHIUM ISOTOPES
MEV RANGE
MEV RANGE 100-1000
MULTIPLICITY
NITROGEN 14 REACTIONS
NUCLEAR FRAGMENTS
NUCLEAR REACTIONS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
PARTITION
RADIATIONS
SPECTRA
STABLE ISOTOPES
TARGETS
TERBIUM 159 TARGET