Space-Based FPGA Radio Receiver Design, Debug, and Development of a Radiation-Tolerant Computing System

Los Alamos has recently completed the latest in a series of Reconfigurable Software Radios, which incorporates several key innovations in both hardware design and algorithms. Due to our focus on satellite applications, each design must extract the best size, weight, and power performance possible from the ensemble of Commodity Off-the-Shelf (COTS) parts available at the time of design. A large component of our work lies in determining if a given part will survive in space and how it will fail under various space radiation conditions. Using two Xilinx Virtex 4 FPGAs, we have achieved 1 TeraOps/second signal processing on a 1920 Megabit/second datastream. This processing capability enables very advanced algorithms such as our wideband RF compression scheme to operate at the source, allowing bandwidth-constrained applications to deliver previously unattainable performance. This paper will discuss the design of the payload, making electronics survivable in the radiation of space, and techniques for debug

ADPF spoke cavity cryomodule concept

The Accelerator Driven Test Facility (ADTF) is being developed as a reactor concepts test bed for transmutation of nuclear waste. A 13.3 mA continuous-wave (CW) proton beam will be accelerated to 600 MeV and impinged on a spallation target. The subsequent neutron shower is used to create a nuclear reaction within a subcritical assembly of waste material that reduces the waste half-life from the order of 10{sup 5} years to 10{sup 2} years. Additionally, significant energy is produced that can be used to generate electrical power. The ADTF proton accelerator consists of room-temperature (RT) structures that accelerate the beam to 6.7-MeV and superconducting (SC) elements that boost the beam's energy to 600-MeV. Traditional SC elliptical cavities experience structural difficulties at low energies due to their geometry. Therefore, stiff-structured SC spoke cavities have been adopted for the energy range between 6.7 and 109 MeV. Elliptical cavities are used at the higher energies. This paper describes a multi-spoke-cavity cryomodule concept for ADTF

Results of the APT RF power coupler development for superconducting linacs.

For the new baseline APT (Accelerator Production of Tritium) linac design, the power couplers are required to transmit 420 kW of CW RF power to the superconducting cavities at 700 MHz. These couplers consist of an airside waveguide-to-coax transition, an air/vacuum break made by two planar, coaxial windows, and a vacuum-side coaxial antenna section. The coaxial antenna allows adjustability of the RF matching to the superconducting cavities. Design, fabrication, and testing of the power coupler/window occurred over the last four years, and room temperature testing of the prototype design is complete. Coupler/window assemblies have transmitted power to 1 MW, CW and have handled full reflected 850 kW, CW over a limited standing-wave phase range. Couplers were tested with a portion of the outer conductor cooled by liquid nitrogen to study the effects of condensed gases. No hard multipacting barriers were encountered during any of this room temperature testing. Final results, conclusions, and lessons learned about the coupler design, fabrication, and testing will be discussed

Status of the LANL Activities in the Field of RF Superconductivity.

Since the last workshop we have tested six b=0.64, 700 MHz, 5-cell elliptical superconducting cavities in collaboration with JLAB in vertical cryostats. All the cavities exceeded the requirements for Accelerator Production of Tritium (APT) (Q0 = 5 x 109 at Eacc = 5 MV/m) with ample margin. The low-field Q0 at 2 K was 2-3 x 1010 and the maximum accelerating field reached 12 MV/m, which corresponds to peak electric and magnetic fields of 41 MV/m and 835 Oe, respectively. Power couplers have also been tested in a test bench up to over 1 MW. Since the APT project has transitioned to Advanced Accelerator Applications (AAA) project, a new type of superconducting accelerating structure called spoke cavity emerged as an excellent candidate for the low energy sections between the RFQ and the elliptical cavities. We tested a b=0.29, 340 MHz, 2-gap spoke cavity on loan from Argonne National Laboratory. The results showed Q0 = 2 x 109 at low fields and a maximum accelerating field Eacc = 12.5 MV/m at 4 K. At 5 MV/m, the Q0 was 1.5 x 109. Encouraged by these results, we started fabricating some spoke cavities and are planning to test one of them in the beamline of LEDA (Low Energy Demonstration Accelerator) in the future