Sohan M. Weeraratne

Biomedical Engineering

As a bioengineering major, Sohan Weeraratne became fascinated by the number of fields to which he could apply his studies. He decided to focus on radiology and was thrilled to be able to be able to conduct research under Professor Molloi’s mentorship. Sohan has become immersed in the vast array of potential radiological nanotube applications and feels honored to have been able to make his own contribution to the field. He plans to continue his research and hopes to pursue graduate studies in medical physics.triangle.gif (504 bytes)




X-ray tubes based on carbon nanotubes suffer from limitations in longevity and stable emission, due to carbon’s chemical characteristics. Our purpose was to develop a high-performance X-ray tube based on titanium dioxide (TiO2) nanotubes. TiO2 nanotubes can be incorporated to increase electron field emission and provide more stable emission. Titanium dioxide is already oxidized and therefore cannot be impeded in ways that carbon can. Also, the metallic features of TiO2 allow it to withstand heating effects. Our technique used an electrochemical setup comprising an electrolyte solution with a titanium sheet submerged in it to oxidize. TiO2 nanotube growth requires only a container, electrolyte, platinum electrode, and DC supply. Manipulating key aspects of growth requirements allowed the temperamental parameter breakthroughs we hoped to attain in the field of nanotechnologic X-ray tubes. Chemical doping during growth and after annealing was one of the main strategies we tested, as was altering the concentration of the electrolyte bath for increased conductance. By analyzing our results, we successfully created nanotubes with increased conductivity, density, and overall pattern of growth.triangle.gif (504 bytes)

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Faculty Mentor                                                                                                                

Sabee Y. Molloi

School of Medicine

The objective of this study is to develop a high-performance X-ray tube based on a cold cathode titanium dioxide (TiO2) nanotube. Currently available thermo-emission cathodes have several important limitations. A potential solution to these limitations is to employ an electron source based on a field emission source. Carbon nanotubes have previously been investigated for use as a cold cathode. However, these types of cold cathodes are limited by their short lifetime. The longevity is of considerable importance when considering adoption in a clinical setting. TiO2 nanotubes show promise to overcome these limitations. A new X-ray tube design using TiO2 nanotubes may be a significant advance in X-ray technology development and could lead to more miniature X-ray sources.triangle.gif (504 bytes)

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