Performance of a low-pressure, helicon driven IEC helium-3 fusion device.

摘要

The study of the 3He(3He,2p)4He fusion reaction is interesting for many reasons ranging from nuclear physics to astrophysics to fusion energy. While this reaction has been studied in particle accelerators, its behavior at low energy ( 1 MeV) is not fully characterized due to low accelerator beam currents ( 1 mA) and the low reaction cross-section. The spherical recirculation of ions in an Inertial Electrostatic Confinement (IEC) device offers the potential to explore these reactions at sub MeV energy levels, but with ion currents as high as 100 mA or more. Such a capability would improve counting statistics tremendously, and be a valuable tool for characterizing this reaction at these low energies.; This dissertation focuses on the development of an IEC device toward this end, with the final goal of detecting 3He(3He,2p) 4He reactions. Many facets of IEC technology were enhanced to accomplish this, and these enhancements will also play a major role in the development of IEC devices for near-term applications.; Some of the major enhancements were: (1) the maximum operating voltage was increased from 55 kV to 170 kV, (2) the lifetime of insulators was increased from about 1 month to 6 months, (3) a gas recycle system was developed that allowed the reuse of 3He gas after it flowed through the system, (4) an ion source was developed that allowed operation at 1/3 the previous minimum pressure with seven times the current, (5) the same ion source was developed to give independent control over the ion current, (6) a proton detection system was developed that reduced the noise level in the detection system by 2 orders of magnitude.; These developments have allowed for the detection of 3He( 3He,2p)4He reactions at the rates of 144 +/- 44 reactions/sec at 124 kV, and 400 +/- 67 reactions/sec at 134 kV, with a maximum total reactivity of 1.1 * 103 reactions/sec. These results agree to within 50% of the theoretical prediction from the combination of beam-background and beam-embedded fusion, and represent the first time 3He-3He reactions have been observed in an IEC device.