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The performance, in-system reprogrammability, flexibility, and reduced costs of SRAM-based field programmable gate arrays (FPGAs) make them very interesting for high-speed on-orbit data processing, but the current generation of radiation-tolerant SRAM-based FPGAs are based on commercial-off-the-shelf technologies and, consequently, are susceptible to single-event upset effects. In this paper, we discuss in detail the consequences of radiation-induced single-event upsets (SEUs) in the state of half-latch structures found in Xilinx Virtex FPGAs and describe methods for mitigating the effects of half-latch SEUs. One mitigation method's effectiveness is then illustrated through experimental data gathered through proton accelerator testing at Crocker Nuclear Laboratory, University of California-Davis. For the specific design and mitigation methodology tested, the mitigated design demonstrated more than an order of magnitude improvement in reliability over the unmitigated version of the design in regards to average proton fluence until circuit failure.

Results of calculations performed in the plane-wave Born approximation for the atomic states of the M-shell are presented in the form of the excitation function I31(?,W), the universal function F31(?/?2,?), and the direct Coulomb ionization cross sections. A description of vacancy filling leading to x-ray production cross sections from incident carbon ions on 79Au, 82Pb, and 83Bi are compared with the present calculations.

POPAE (Protons on Protons and Electrons) is a storage ring facility at the Fermilab on a scale suitable to permit the collision of 1000 GeV protons with 1000 GeV protons and with electrons of an energy compatible with that scale. In this paper, we summarize our work thus far on the lattice and layout of the proton storage rings. Though the 1000 GeV physical scale is maintained, the design is developed in a 400 GeV context. The proton rings form a racetrack, the two long straight sections of which are each about 1 km in length. Each long straight section contains a number of matched lattice insertions, as well as uncommitted space for additional development. Depending on the assumptions made concerning the beam-beam limit (as yet unknown experimentally), maximum luminosities are calculated to be in the range from 1033 to 1034cm-2 sec-1.

A 115 MeV proton beam has been successfully cooled in the Electron Cooling Ring at Fermilab. Initial experiments have measured the longitudinal drag force, transverse damping rate, and equilibrium beam size. The proton beam was cooled by a factor of ~50 in momentum spread in 5 sec, and by a factor of 3 in transverse size in 15 sec. Long term losses were consistent with single scattering from residual gas, with lifetime ~1000 sec. Using the measured electron beam temperature Te= 0.8(2) eV, the observed cooling agrees well with expectations from cooling theory.

The low design of the low-beta insertion installed at the BO straight section of the Tevatron is presented. This design replaces two of the regular lattice quadrupoles with stronger, separately powered quadrupoles and adds an additional triplet in the free space on either side of the interaction point. By varying the four separate quadrupole circuits, and two trim quadrupole tuning circuits, it is possible to go smoothly from the normal, fixed-target configuration with s* = 75 m in each plane to the colliding-beam mode of operation with s* = 1 m in each plane, while maintaining a constant tune for the Tevatron.

The RF window vacuum seals on the 400-GeV Fermilab accelerating RF cavities are very large circular cylinders of alumina. The cavities were first installed with seals of 94% purity Al2O3. Several of these seals failed in high-power operation due to dielectric heating. Higher purity ceramics (99.5% Al2O3) have been obtained and are now being installed. The complex permitivity of both types of ceramic has been measured in a TM010 mode test cavity ten-inches high and eight feet in diameter. Frequency shift and Q shift data have been analyzed by perturbation analysis and by computer programs. Results confirm that the higher purity ceramics have a loss tangent a factor of five better than the original seals. Some high-power operational test results are also presented.

A proposal has been developed for the construction of a 1000 GeV on 1000 GeV colliding beam facility at Fermi National Accelerator Laboratory. To achieve the same 2000-GeV center-of-mass energy with a fixed target accelerator would require a beam of more than 2 × 106 GeV. The total circumference of the facility is 5520 m, including six straight sections, each 200 m long. Injection from the Fermilab main ring or Energy Saver/Doubler (ES/D) will be at the energy desired for interactions, thus avoiding the uncertainty, complication, and cost of accelerating very intense beams in the storage rings themselves. Each ring will require 570 superconducting dipole magnets, each 6.2 m long; the field required at 1000 GeV is 60 kG. For a proton current of 5A in each ring at 1000 GeV, the high-luminosity insertion is designed to give L = 4 × 1033 cm-2 sec-1. The proposal was developed during an intensive study from November 1975 to April 1976. This study drew not only on the experience of the CERN ISR2 and previous Fermilab designs, but also on studies of high energy storage rings made at Brookhaven National Laboratory (Isabelle)4 and at CERN (LSR).5

It has recently been suggested1 that the present high energy synchrotrons at CERN and Fermilab could be operated as pp storage rings with a center-of-mass energy of some 800 GeV. The Fermilab Energy Doubler/Saver, in addition, would be quite suitable as a high performance storage ring, producing collisions at 2 TeV in the center-of-mass. In order to achieve useful luminosity it is necessary to: 1) collect antiprotons from ˜-80 GeV protons colliding on a stationary target, 2) cool the phase space of the initially diffuse p's, and 3) accumulate the cooled p's over cycles. Several methods have been devised to carry out this repetitive accumulation and cooling. 2,3,4

Four types of insertions are described for the six 200-m straight sections of POPAE. All have dispersion matched to zero. (1) Injection-ejection insertion - This has proper high-6 values and phase advances for horizontal injection and vertical ejection. (2) Phase-adjust insertion - The phase advance in this insertion is adjustable over a range of ~100°. (3) Generalpurpose insertion - The s* is adjustable from 2.5 to 200 m and the crossing angle is adjustable from 0 to 11 mrad. (4) High-luminosity insertion - This gives an even lower s* of 1 meter.

The "cooling" of protons by electrons has been studied by the accelerator group at the Institute of Nuclear Physics at Novosibirsk, U.S.S.R.l. They have achieved damping of proton-betatron oscillations by Coulomb interactions with "cold" electrons as described by simple theory. They also observe fast damping when the longitudinal velocities of all the protons and electrons are very nearly the same and the electrons are trapped in a longitudinal magnetic field. This effect results from the extended interaction between the same electrons and protons.

Simple test lattices for a 20 TeV superconducting super collider have been designed based on each of the major dipole designs, 3, 5, 6, and 6.5 Tesla. These lattices have been made as nearly identical as possible. The reason for different lattices is to be able to evaluate equally the different magnet designs, with associated multiple distributions and persistent current errors, through analytical and tracking programs without the complications of different lattice designs. It should be noted that while these designs are typical of a 20 TeV SSC, they are meant only for study and do not represent a machine which would be built. Thus, they do not have crossing magnets or utility insertions. However special phase shifting sections called Phase Trombones are included, a feature not present in most of the previous SSC lattice designs.

The design of a 75-m radius, 8-GeV storage ring to be used for stochastic cooling and accumulation of antiprotons is described. The stochastic cooling systems have imposed strenuous requirements on the lattice and the resulting ring design is rather novel.

Successful electron cooling of antiproton beams requires a precisely aligned and high quality electron beam. Mean e- momentum and energy are to be held within 0.25 mrad and ? eV respactively. In addition the e- "temperature" about this mean (rest frame velocity spread) should be held to ?? eV. The diagnostics required to align the beam in angle and energy are rather straightforward. The temperature measuring diagnostics (one for T?; one for T?) are more exotic.

Operator shift methods in differential equations theory have analogies in difference equations theory. These techniques may be useful in finding the complementary solution and often the particular solution, as well as in providing insight into the relation between the roots of the characteristic equation and the form of the solution.