Optimized Deuterium Ionizer for Pulsed and Continuous Neutron Sources for Well Logging Applications

The development of non-radioisotope sources for a variety of applications is of great interest for nuclear non-proliferation. We propose to develop an improved, cost-effective deuterium ionizer as part of a downhole neutron source that require a robust, efficient, controlled ion output. Short time duration pulses of D+ and D2+ ions for acceleration onto deuterated/tritiated targets allows synchronization with detectors which can improve signal-to-noise and enhance background rejection. Traditionally, the design of deuterium ionizers has relied on hot-wire thermionic sources of electrons, confined by magnetic fields, immersed in deuterium gas (D2), to form a plasma with a beam-forming extraction electrode. In this work, the charge multiplication step will be combined with the gas evolution step using the large surface area-to-volume ratio provided by a multichannel plate (MCP) geometry. Electrons injected at the entrance are multiplied by the high secondary electron yield (SEY) inner-wall coatings. The same wall surfaces are coated with titanium (Ti) to provide for deuterium gas gettering. To improve efficiency and lower power requirements, we will investigate MCP-based electron sources for the ionization process, along with efficient ion transport tubes. During Phase I, Xelera will carried out detailed simulations then build and test a prototype ionizer. In Phase II, Xelera will build and test a complete optimized neutron generator and test it with an oil well service company. Xelera Research LLC has extensive experience in nuclear process modeling and in the design of electron and ion beams, vacuum, and associated hardware used in wireline inspection. These are critical competencies to optimizing the design of highly efficient, compact, and rugged deuterium ionizer. Xelera, with broad experience in simulation and engineering, and has the skills and personnel to tackle this project.