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Phosphors are materials that are doped with trace elements that give off visible light when excited. Many phosphors have a ceramic base and can survive and function at high temperatures. Research has shown that the fluorescence decay time can be used to measure temperatures in adverse environments, such as those found in space. Development of space-based phosphor sensors will depend heavily upon research investigating the resistance of phosphors to ionizing radiation and the ability to anneal damage caused by ionizing radiation. Preliminary results indicate that a consistent increase in the fluorescence decay time after thermal cycling was observed at two measured 3 MeV proton fluences. This “annealing” of proton damage was observed over the entire measured temperature range. The more heavily irradiated ZnS:Mn samples did not have annealed decay times that were as large as those that received lesser radiation fluences. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We report the results of our investigation of producing nanoclusters of Au in silica using post bombardment by MeV silicon. This technique has resulted in producing Au-nanoclusters at fluences of two orders of magnitude less than what is traditionally used. This is accomplished by first implanting Au into silica, then subsequently bombarding the silica with MeV Si ions. The size of the nanoclusters, ranging from 1 to 10 nanometers, is controlled by the implantation dose and total electronic energy deposited by post implantation-bombarding ions in the implanted layer. With the use of an indirect measurement method, such as optical absorption spectrophotometry (non-destructive), and a direct method, such as transmission electron microscopy (destructive), we show how, and at what concentrations, metallic ions nucleate to form nanoclusters by irradiation assisted nucleation at a dose below that needed for spontaneous nanocluster formation. [ABSTRACT FROM AUTHOR]

Hydrogen is perhaps the most common elemental contaminant that appears in thin film materials, and can have dramatic effects on material's properties. Most modern analytical techniques are incapable of hydrogen detection. Because of this, special ion beam techniques based on resonant nuclear reactions have been developed to fill this gap in material analysis [1]. The yield of the resulting gamma-rays is proportional to the hydrogen content within a very narrow depth region which satisfies the resonant energy "window". Such setups have been developed at SUNY at Albany, and GSI in Germany. The setup developed at the Center for Irradiation of Materials of Alabama A&M University has an active protection against the parasitic radiation, that can reduce the detecting threshold to .1 ppm. The full description of the assembly, as well as experimental results on profiling hydrogen amounts in different materials is provided below. [ABSTRACT FROM AUTHOR]

Using a 5SDH-2 tandem accelerator, at the Center for Irradiation of Materials of Alabama A&M University we have developed facilities for ion beam based studies of materials, such as PIXE, RBS/Channeling, NRA/Hydrogen Profiling. The RBS/Channeling setup (experimental chamber and attached software for data acquisition and analysis), provided by NEC, has a goniometer with 4 degrees of freedom, two linear upon the x and z axes, and two rotational upon the theta (around the z axis) and phi (upon the y axis — beam axis). We designed an addition to this setup to allow us to perform double alignment channeling. A description of the setup, as well as double alignment channeling results are presented in this paper. [ABSTRACT FROM AUTHOR]