PROTON-NUCLEUS COLLISIONS IN THE THRESHOLD REGION AND THE DROPLET MODEL OF FRAGMENTATION
Abstract
This thesis contains the details of the experimental setup and final results of Brookhaven Nat'l Laboratory (BNL) E-778. The experimental objective was to study proton induced nuclear fragmentation using an internal gas jet target. The facility was specifically designed for this experiment and installed in the AGS main ring. The fragment charge was between 2 and 14 and the kinetic energy (5 to 100 Mev) were determined as a function of incident proton energy for a scattering angles in the lab frame of 48.5(DEGREES) and 131.5(DEGREES). Fragment production cross sections are observed to rise drastically (about 10 times) for incident proton energies between 1 and 10 Gev, while above 10 Gev, fragment production appears to be independent of the incident proton energy. The measured fragment charge-yield was found to obey a power law of the form, Yield (PROPORTIONAL) Z(,f)('-(tau))'' (3 < Z(,f) < 14). (tau)'' is dependent on the incident proton energy and minimum is reached in between 3 and 4 Gev. At the high energy side the fitted (tau)'' are found to agree (within 10%) with the fitted ones from a previous internal target experiment (E-591) conducted at FNAL, where the lowest available proton energies were 50 Gev. From previous analysis by Sangster, it is concluded that, in the threshold region, two fragment production mechanisms are observed. Although insufficient information is available to uniquely separate the two components, certain features of the asymmetric fission mechanism are identified.
Degree
Ph.D.
Subject Area
Nuclear physics
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