U.S. Department of Energy Burns and Roe Enterprises In Cooperation with General Atomics 135-b Central Park Square Los Alamos NM 87544

A -- FABRICATION OF A PROTOTYPE 700 MHZ MEDIUM BETA SUPERCONDUCTING CAVITY FROM RRR GRADE 250 NIOBIUM SHEETS OF THICKNESS 4MM BY DEEP DRAWING, SPINNING OR HYDROFORMING, AND ELECTRON BEAM (EB) WELDING TO QUALIFY U.S. OWNED AND OPERATED FIRMS ONLY SOL NA DUE 072798 POC Point of Contact: Frank Targhetta 505-661-4624. Contracting Officer: Frank Targhetta 505-661-4624. Engineering Development and Demonstration (ED&D) efforts are underway by the Purchaser to support the Accelerator Production of Tritium (APT) Project. One goal of this activity is to demonstrate the technology and provide the basis for the Preliminary and Final Design of a Superconducting Radio Frequency (SCRF) cavity and cryomodules for the High Energy (HE) proton linear accelerator (linac) that will accelerate a 100 mA proton beam to an energy of 1.7 GeV. The HE linac will accelerate protons in a SCRF cavity fabricated from high purity, RRR grade 250 bulk niobium (Nb). If APT construction is approved, the HE linac will require 400 cavities (90 medium-beta (b = 0.64) and 312 high-beta (b = 0.82), assembled in 108 cryomodules. In a previous unrestricted procurement for a limited quantity (4) of such cavities, Purchaser awarded the contract to a foreign firm. In that procurement, U.S. firms were invited to propose and one firm offered a proposal that was not selected. The explicit programmatic objective for this procurement is to cultivate the capability of U.S. firms to provide cavities for the APT Project. To that end, Purchaser will provide certain materials and equipment but interested vendors will also be required to invest capital and other resources as described below. Cavity fabrication process includes rough-cut flat pattern blank from RRR grade 250 Nb sheet lot; half-cell formation by deep drawing, spinning or hydroforming; pulling nipples on beam tubes; brazing stainless steel conflat flanges to Nb tubes; machining weld-preps; electron beam (EB) welding of half-cells (iris and equator welds); EB welding of half-cells to beam tubes. At the operating temperature of 2 K, the cavity shall reach the accelerating gradient Eacc? 6.5 MV/m and the unloaded quality factor of Qo?5x109. To meet these goals, the qualified U.S. Contractor will be required to: 1. Provide all necessary materials (except for Purchaser furnished niobium (Nb)), equipment (except for Purchaser furnished tooling), consumable supplies, labor, supervision, engineering, facilities, inspection, testing equipment and services needed to meet the requirements of a resulting contract. Contractor shall have access to a fully operational electron beam (EB) welding apparatus capable of handling structures as large as 19" diameter and 48" in length. 2. Have corporate and personnel experience in forming, machining, and EB welding of high purity Nb. 3. As Purchaser's funding is limited and will not exceed $125,000.00, the Contractor will be required to invest its own capital to cover the majority of the cost of production of this cavity. Posted 07/14/98 (D-SN223200). (0195)

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