A search for theoretically predicted collective high spin states in $\sp{12}$C is made by making a kinematically complete measurement of the three alpha-particles produced in the decay of excited $\sp{12}$C. This is accomplished by using a system of position sensitive detectors to detect the three alpha-particles in coincidence. The excited $\sp{12}$C is produced in the system $\sp{12}$C + $\sp{12}$C, with a lab energy of 90 MeV. / From event reconstruction, different reaction and decay processes in this system are identified and separated as much as kinematically allowed. The event reconstruction is accomplished with general computer programs written for this work. In addition, a general purpose program was written to do Monte Carlo simulations of these detector systems to determine detection efficiency for a particular reaction and decay process, and for use in calculating double-differential cross sections. / Many known states in $\sp{12}$C were identified with good resolution, including two states (and possibly two other states as well) not previously seen in this system. In addition, a significant amount of highly excited $\sp{16}$O is produced, which decays to the same four-body final state resulting from the decay of $\sp{12}$C. Many states in $\sp{16}$O were observed, including structures at excitation energies of about 25 MeV and 30 MeV, which have been observed previously. For both the $\sp{12}$C and the $\sp{16}$O observed in the spectra, a sequential decay process is strongly indicated. It is estimated that less than 5% of the $\sp{12}$C decays observed are the result of direct breakup, or ternary decay. The production and decay of $\sp{20}$Ne could not be identified in the data. / Despite the low background and relatively good energy resolution, no predicted, but as yet unseen, states were uncovered in this work. However, from the event reconstruction and the calculation of detection efficiency, the branching fraction for the decay of $\sp{12}$C from the 4$\sp+$ state at 14.08 MeV excitation is calculated to be 0.81 with an estimated uncertainty of about 0.05. / Source: Dissertation Abstracts International, Volume: 51-04, Section: B, page: 1888. / Major Professor: Neil R. Fletcher. / Thesis (Ph.D.)--The Florida State University, 1990.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78242 |
| Contributors | Caussyn, David Dwaine., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 217 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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