NASA SBIR 00-II Solicitation

TECHNICAL ABSTRACT (LIMIT 200 WORDS)
A proton collimator would convert fusion products emitted isotropically from an IEC fusion core into a directional beam of high-energy particles. This collimated beam could then be introduced to direct energy converters, direct proton thrusters, or evaporative thrusters for space propulsion. Another important characteristic of the collimator is that it separates leaking low-energy fuel components from the energetic fusion protons. This fuel could then be pumped out and recycled, avoiding losses of valuable fusion fuels into space.
The physical and engineering feasibility of a simulation experiment with a small-scale electron collimator was successfully demonstrated in the Phase I project. Accordingly, simulation experiments are recommended prior to a full-scale proton collimator experiment as a next step to save costs and to obtain basic performance results quickly. The proposed Phase II electron collimator could employ a unique spherical filament emitter to produce an isotropic 600-eV electron beam, simulating 15-MeV fusion proton effects in the unit. The collimator performance would be studied and the sensitivity of the unit determined with respect to space potential, off-axis position of electron sources, while other auxiliary parameters would be clarified. Separation and recycle of fuel icons would also be studies. Phase II results, including the physics database and benchmark computer codes, would be utilized in designing Phase III experiments on the proton collimator at a larger facility.

POTENTIAL COMMERCIAL APPLICATIONS
The primary commercial application for this invention would be for advanced spacecraft propulsion. Both operation modes considered are useful: the evaporating target thruster provides a ultra-high thrust propulsion unit while the direct energy converter version can be used for generation of electricity for use with am electrical thruster or for spacecraft electrical systems. Direct exhaust of the protons can also be considered as a hybrid ultra-high impulse propulsion unit.
Combined with the IEC fusion unit, the proton collimator also has the near-term potential of providing a large commercial market in intense proton-beam technology. It provides an inexpensive and intense proton beam in the important energy range of a few MeV through 15-MeV. Non-electrostatic accelerators such as linear accelerators or proton cyclotrons presently provide MeV proton beams, but their beam intensities are weak and irradiation costs are expensive. Once a multi- kW IEC fusion unit is achieved, several mA's of 15-MeV proton beam could be delivered at relatively low cost with a collimator. This simultaneously provides an important step towards scale-up of the IEC to power plant level. Thus, commercialization of the proton collimator is anticipated in an early stage of IEC fusion core development.

NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR (Name, Organization Name, Mail Address, City/State/Zip)
Hiromu Momota
NPL Associates
912 W. Armory Ave
Champaign , IL   61821 - 4537

NAME AND ADDRESS OF OFFEROR (Firm Name, Mail Address, City/State/Zip)
NPL Associates
912 W. Armory Ave
Champaign , IL   61821 - 4537