The objective of this research is to build a prototype of a carbon nanotube (CNT)-based micro X-ray tube array, which can be used in a real-time cone-beam computed tomography (CT) scanner for cancer research. The X-ray tube array consists of an electron source, control grids, focusing electrodes, and an anode plate. All the experiments have been executed in an ultra high vacuum environment at a pressure of 10⁻⁷ Torr. A thin film consisting of multi-wall carbon nanotubes (MWNTs) was used as the electron source. A diode configuration was employed to test the field emission performance of the CNT thin film. The current density achieved was 1mA/cm² at 10V/µm. After the initial burn-in process, a relatively steady emission current was obtained for duration of 170 hours. The control grid was made of 25% opening space stainless steels mesh. Meshes with different wire diameters were tested in a triode structure, and some differences were observed. Multi-anode field emission tests and multi-tube electric field simulations were executed. Experiments and simulations have revealed crosstalk between pixels during field emission. Based on the above experiments and simulations, a signal pixel prototype has been fabricated and is being tested. Moreover, some potential optimizations that will be used in the second prototype are also discussed
| Identifer | oai:union.ndltd.org:WATERLOO/oai:uwspace.uwaterloo.ca:10012/3976 |
| Date | 29 August 2008 |
| Creators | Sun, Yonghai |
| Source Sets | University of Waterloo Electronic Theses Repository |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
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