When target and projectile nuclei have a difference in neutron to proton ratio (N/Z),
the quasiprojectiles formed in a deep inelastic collision (DIC) should have a mean
N/Z between the N/Z of the target and the N/Z of the projectile, depending on the
amount of N/Z equilibration that occurred. Data from six reaction systems at two
beam energies (32 and 45 MeV/nucleon) were collected. The systems in order of
increasing difference between target and projectile N/Z (shown in parentheses) are
40Ar + 112Sn (âÂÂN/Z = 0.018), 48Ca + 124Sn (âÂÂN/Z = 0.080), 48Ca + 112Sn (âÂÂN/Z
= 0.160), 40Ca + 112Sn (âÂÂN/Z = 0.240), 40Ar + 124Sn (âÂÂN/Z = 0.258) and 40Ca +
124Sn (âÂÂN/Z = 0.480).
The quasiprojectile N/Z was determined by two techniques. The first technique
used the isotopically resolved fragments to reconstruct the quasiprojectile N/Z. The
second technique, developed in this thesis, used fragment yield ratios and a simple
equation to simultaneously fit all six systems to determine the quasiprojectile N/Z.
Simulations and a filter of the FAUST (Forward Array Using Silicon Technology) acceptance
were used to calculate neutron loss; this accounted for the difference between
the two techniques.
To study the fragmentation of quasiprojectiles the fragment yields were used to
calculate the isobaric, isotopic, fractional and mean N/Z yields. The results showed
that as neutron richness increased, more neutron-rich fragments were produced. In addition observation showed evidence for an inhomogeneous distribution of N/Z between
the light charged particles (LCPs Z less than 3) and intermediate mass fragments
(IMFs Z greater than 2).
The theoretical results, which used different values of the symmetry energy, were
compared to experimental data to determine which symmetry energy best represents
the experimental data. The comparison showed the experimental data was the overall
best fit with a lower value of the symmetry energy. These results were not conclusive
and further investigation is required.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/5886 |
| Date | 17 September 2007 |
| Creators | Keksis, August Lawrence |
| Contributors | Yennello, Sherry J. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 9653885 bytes, electronic, application/pdf, born digital |
Page generated in 0.0019 seconds