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Heaters for Electron Guns


OBJECTIVE: The objective is to develop alternative manufacturing processes design and/or materials to improve the heater system in dispenser type cathodes. DESCRIPTION: Currently the Navy is using Rhenium-Tungsten heater wire used in existing vacuum tube technologies (Refs. 1, 2, 3, 4, 5) for its electron guns. Domestic manufacturing sources for this type of heater wire are decreasing causing a continual increase in the costs to both government and industry to manufacture and purchase the wire. Various factors combine to create the diminishing manufacturing base. The need for the wire is a low volume requirement; the current manufacturing processes are labor intensive; and the materials to manufacture the wire are in foreign countries. The Navy has researched current materials and there are no materials on the market that would meet the current desired replacement. This situation results in a two-fold need. One is to develop new low cost materials for the heater wire. The other is to develop the manufacturing and producibility processes for the newly developed materials. The Navy needs a new design technology that facilitates establishment of additional domestic providers of the heater wire. The new technology may be an innovative manufacturing process, new materials that replace the current Rhenium-Tungsten heater wire, or a combination of both. This technology will replace the current 0.015-0.029 inch diameter Rhenium-Tungsten wire. The new technology must lower the costs and meet the current requirements of the heater system wire including electrical and mechanical performance and reliability, thus addressing system availability. The Navy anticipates the desired technology will replace the wire used in the electron gun heater wire assemblies in magnetrons, klystrons, and Traveling Wave Tubes (TWTs). The Phase I effort will not require access to classified information. If need be, data of the same level of complexity as secured data will be provided to support Phase I work. The Phase II effort will likely require secure access, and the contractor will need to be prepared for personnel and facility certification for secure access. PHASE I: The company will develop concepts for an improved electron gun heater system that meet the requirements described above. The contractor will demonstrate the feasibility of their technology to meet the Navy need and show their concept can be feasibly developed into a useful product for the Navy. Feasibility will be established by material component testing and analytical modeling or a combination of these. The small business will provide a Phase II development plan with performance goals and key technical milestones, and that will address technical risk reduction. PHASE II: Based on the results of Phase I and the Phase II development plan, the contractor will develop a process/capability prototype for evaluation. The evaluation will determine the capability of the prototype to meet the Navy performance goals defined in the Phase II development plan and the Navy application requirements for microwave tubes such as magnetrons, klystrons, and TWTs with the electron gun heater technology. The performance will be demonstrated through material processing, prototype evaluation and modeling, or analytical methods for all application performance parameters. Evaluation results will be used to modify the prototype design and manufacturing processes to meet Navy requirements for an operational electron gun heater. The contractor will prepare a Phase III development plan to transition the technology for Navy use. PHASE III: If Phase II is successful, the contractor will be expected to support the Navy in transitioning the technology into manufacturing for Navy use. The contractor will be responsible for prototype design changes based on results of operationally relevant environment testing. The contractor will support the Navy for test and validation to certify and qualify the manufacturing and heater systems for Navy use. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Microwave tubes with dispenser cathodes are utilized in many military systems and commercial or government systems. This topic addresses manufacturing capabilities and material to support many microwave tubes such as magnetrons, klystrons, and TWTs used in Navy and commercial applications. Rhenium-Tungsten wire is currently used for heating elements in high temperature furnaces, thermocouples, and in electronics. The new capabilities and materials would have commercial applications. REFERENCES: 1. Hoover, Barry; Effgen, Michael."Cathode Manufacturing Globalization and its Effect on Instability in the Metals Market on Cathode Pricing", Proceedings of the 2008 IEEE International Vacuum Electronics Conference (9th) (IVEC 2008), Held in Monterey, CA on April 22-24, 2008. 2. Lough, Walt."DLA Strategic Materials information Briefing", 30 June, 2011,>3."Reestablishing Strategic and Critical Material Security in the Department of Defense", 11 May 2011, 4. China Tungsten Industry report 2010-2011, 5."Reconfiguration of the National Defense Stockpile"Report to Congress April 2009,
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