Abstract: The University of Arizona 2 MV Van de Graaff accelerated 1 MeV protons to bombard aerogel targets. The spectroscopic emission characteristics of proton bombarded aerogels 1.68 mm - 5.50 mm thick were studied, particularly the emission as a function of bombardment time. It was discovered that the intensities of proton bombarded aerogel emissions depend on proton beam current, emitted wavelength, aerogel thickness, observation position inside of the gel, the time the aerogel is bombarded in a particular experiment, the time the aerogel had been bombarded prior to an experiment, and the time elapsed between experiments. Increasing the current gives a higher emission, but the intensity is not directly proportional to current. Thicker aerogels are less affected by beam current changes. The spectrum (lambda 3500 - 7000 A ) from an aerogel is a continuum, reaching a maximum in the range lambda 4300 - 5300 A . The maximum is red shifted as current is increased and blue shifted as bombardment time is decreased. when protons first make contact with an aerogel, a strong intensity peak is observed, which then decays to a near constant value. In general, proton bombarded aerogel emission decreases with time bombarded prior to an experiment and increases with the time elapsed between experiments. The front of an aerogel (where the protons first make contact with it) is the point of maximum intensity. The point of maximum intensity moves downstream from the front of the aerogel as bombardment time increases. Since no spectral lines of hydrogen were seen, we suspect that we need thinner and/or less dense aerogels, and higher proton energy. Luminescence is the most likely form of emitted radiation.
| Limitations: |
 APPROVED FOR PUBLIC RELEASE |
| Description: |
Master's thesis |
| Pages: |
82 |
| Report Date: |
04 AUG 1998 |
| Report Number: |
A202453 |
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