A cooperative group instructional strategy is being used to teach a unit on neutron transport and diffusion theory in a first-year-graduate level, Reactor Theory course that was formerly presented in the traditional lecture/discussion style. Students are divided into groups of two or three for the duration of the unit. Class meetings are divided into traditional lecture/discussion segments punctuated by cooperative group exercises. The group exercises were designed to require the students to elaborate, summarize, or practice the material presented in the lecture/discussion segments. Both positive interdependence and individual accountability are fostered by adjusting individual grades on the unit exam by a factor dependent upon group achievement. Group collaboration was also encouraged on homework assignments by assigning each group a single grade on each assignment. The results of the unit exam have been above average in the two classes in which the cooperative group method was employed. In particular, the problem solving ability of the students has shown particular improvement. Further,the students felt that the cooperative group format was both more educationally effective and more enjoyable than the lecture/discussion format.

The Sandia National Laboratories (SNL) Data Encryption Standard (DES) Application Specific Integrated Circuit (ASIC) is the fastest known implementation of the DES algorithm as defined in the Federal Information Processing Standards (FIPS) Publication 46-2. DES is used for protecting data by cryptographic means. The SNL DES ASIC, over 10 times faster than other currently available DES chips, is a high-speed, filly pipelined implementation offering encryption, decryption, unique key input, or algorithm bypassing on each clock cycle. Operating beyond 105 MHz on 64 bit words, this device is capable of data throughputs greater than 6.7 Billion bits per second (tester limited). Simulations predict proper operation up to 9.28 Billion bits per second. In low frequency, low data rate applications, the ASIC consumes less that one milliwatt of power. The device has features for passing control signals synchronized to throughput data. Three SNL DES ASICS may be easily cascaded to provide the much greater security of triple-key, triple-DES.

When the Lanczos method is used to compute eigenvalues, it is often restarted or used with the shift-and-invert scheme. The restarted scheme usually uses less memory but the shift-and-invert scheme is more robust. In addition, the shift-and-invert Lanczos method requires accurate solutions of a series of linear systems. Parallel software packages suitable for these linear systems are only started to become available. In this talk, we will present our evaluation of two such packages and briefly examine when it is necessary to use the shift-and-invert scheme.

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Optical Micro Electro Mechanical Systems (Optical MEMS) Technology holds the promise of one-day producing highly integrated optical systems on a common, monolithic substrate. The choice of fabrication technology used to manufacture Optical MEMS will play a pivotal role in the size, functionality and ultimately the cost of optical Microsystems. By leveraging the technology base developed for silicon integrated circuits, large batches of routers, emitters, detectors and amplifiers will soon be fabricated for literally pennies per part. In this article we review the current status of technologies used for Optical MEMS, as well as fabrication technologies of the future, emphasizing manufacturable surface micromachining approaches to producing reliable, low-cost devices for optical communications applications.

The interaction of plasmas with intense lasers is an excellent example of how different fields of physics are inter-connected. Invention of the laser and its ongoing development has allowed the creation and study of high temperature, dense matter in the laboratory. The results both advance the underlying plasma science and are relevant to many fields ranging from astrophysics to fusion and nonlinear physics. A brief overview of the interaction physics is given. Selected topics are discussed to illustrate the exciting progress in experimental, theoretical and computational investigations with focused laser intensities up to 10{sup 21} W/cm{sup 2}.

Single-top-squark production probes R-parity-violating extensions of the minimal supersymmetric standard model though the {lambda}{sub 3ij}{double_prime} coupling. For top-squark masses in the range 180-325 GeV, and {lambda}{sub 3ij}{double_prime} > 0.02-0.06, we show that discovery of the top squark is possible with 2 fb{sup {minus}1} of integrated luminosity at run II of the Fermilab Tevatron. The bound on {lambda}{sub 3ij}{double_prime} can be reduced by up to an order of magnitude with existing data from run I, and by two orders of magnitude at run II if the top squark is not found.

We have observed low threshold operation of a broadly tunable (2.18-3.4 µm) pump-resonant cw periodically poled lithium niobate (PPLN) optical parametric oscillator (OPO). When pumped at 806 nm with 410 mW from a custom-built diode laser the OPO generated 20 mW of idler output at 3.3 µm.

We report the determination of sin{sup 2}{theta}{sub W} in {nu}-N deep inelastic scattering from the NuTeV experiment. Using separate neutrino and anti-neutrino beams, NuTeV is able to extract sin{sup 2}{theta}{sub W} with low systematic errors from the Paschos-Wolfenstein variable R{sup -}, a ratio of differences of neutrino and anti-neutrino neutral-current and charged-current cross-sections. NuTeV measures sin{sup 2}{theta}{sub W} {sup (on - shell)} = 0.2253 {+-} 0.0019(stat) {+-} 0.0010(syst), which implies M{sub W}= 80.26 {+-} 0.11 GeV.

A self-verifying temperature sensor that employs advanced contact thermocouple probe technology was tested in a laboratory-scale, joule-heated, refractory-lined glass melter used for radioactive waste vitrification. The novel temperature probe monitors melt temperature at any given level of the melt chamber. The data acquisition system provides the real-time temperature for molten glass. Test results indicate that the self-verifying sensor is more accurate and reliable than classic platinum/rhodium thermocouple and sheath assemblies. The results of this test are reported as well as enhancements being made to the temperature probe. To obtain more reliable temperature measurements of the molten glass for improving production efficiency and ensuring consistent glass properties, optical sensing was reviewed for application in a high temperature environment.

As part of the International Criticality Benchmark Evaluation Project, 26 experiments are analyzed for use as benchmark experiments for validation of computer codes and cross sections. The experiments consisted of water-moderated plutonium metal arrays of size 2x2xN, where N =2-5 or 3x3x3. Of the 26 experiments, 22 were chosen to develop benchmark models which are described in detail, including geometry and material data. A sensitivity study was performed to determine the uncertainty on the keff value due to measurement uncertainties or limits of accuracies. For all benchmark models, keff values were found using MCNP with continuous-energy ENDF/B-V cross sections, MCNP with continuous energy ENDF/B-VI cross sections, and KENO-V.a with 27-group ENDF/B-IV cross sections. For one case, the codes overestimated keff by more than 1%. The experiments were grouped for three parameters: plutonium mass, horizontal spacing, and vertical spacing. For each parameter, a bias value was found. In all cases, MCNP with ENDF/B-VI cross sections had the smallest difference in the average keff. This same result was found when all experiments were grouped together. However, if the one experiment that was significantly overestimated was excluded, the smallest difference in the average keff was found for KENO-V.a with ENDF/B-IV cross sections.

Anisotropic, smooth etching of the group-III nitrides has been reported at relatively high rates in high-density plasma etch systems. However, such etch results are often obtained under high de-bias andlor high plasma flux conditions where plasma induced damage can be significant. Despite the fact that the group-III nitrides have higher bonding energies than more conventional III-V compounds, plasma-induced etch damage is still a concern. Attempts to minimize such damage by reducing the ion energy or increasing the chemical activity in the plasma often result in a loss of etch rate or anisotropy which significantly limits critical dimensions and reduces the utility of the process for device applications requiring vertical etch profiles. It is therefore necessary to develop plasma etch processes which couple anisotropy for critical dimension and sidewall profile control and high etch rates with low-damage for optimum device performance. In this study we report changes in sheet resistance and contact resistance for n- and p-type GaN samples exposed to an Ar inductively coupled plasma (ICP). In general, plasma-induced damage was more sensitive to ion bombardment energies as compared to plasma flux. In addition, p-GaN was typically more sensitive to plasma-induced damage as compared to n-GaN.

Advanced rechargeable lithium-ion batteries are presently being developed and commercialized worldwide for use in consumer electronics, military and space applications. The motivation behind these efforts involves, among other things, a favorable combination of energy and power density. For some of the applications the power sources may need to perform at a reasonable rate at subambient temperatures. Given the nature of the lithium-ion cell chemistry the low temperature performance of the cells may not be very good. At Sandia National Laboratories, we have used different electrochemical techniques such as impedance and charge/discharge at ambient and subambient temperatures to probe the various electrochemical processes that are occurring in Li-ion cells. The purpose of this study is to identify the component that reduces the cell performance at subambient temperatures. We carried out 3-electrode impedance measurements on the cells which allowed us to measure the anode and cathode impedances separately. Our impedance data suggests that while the variation in the electrolyte resistance between room temperature and -20"C is negligible, the cathode electrolyte interracial resistance increases substantially in the same temperature span. We believe that the slow interracial charge transfer kinetics at the cathode electrolyte may be responsible for the increase in cell impedance and …

Corrosion of spent UO{sub 2} fuel has been studied in experiments conducted for nearly six years. Oxidative dissolution in vapor and dripping groundwater at 90 C occurs via general corrosion at fuel-fragment surfaces. Dissolution along fuel-grain boundaries is also evident in samples contacted by the largest volumes of groundwater, and corroded grain boundaries extend at least 20 or 30 grains deep (> 200 {micro}m), possibly throughout millimeter-sized fragments. Apparent dissolution of fuel along defects that intersect grain boundaries has created dissolution pits that are 50 to 200 nm in diameter. Dissolution pits penetrate 1-2 {micro}m into each grain, producing a ''worm-like'' texture along fuel-grain-boundaries. Sub-micrometer-sized fuel shards are common between fuel grains and may contribute to the reactive surface area of fuel exposed to groundwater. Outer surfaces of reacted fuel fragments develop a fine-grained layer of corrosion products adjacent to the fuel (5-15 {micro}m thick). A more coarsely crystalline layer of corrosion products commonly covers the fine-grained layer, the thickness of which varies considerably among samples (from less than 5 {micro}m to greater than 40 {micro}m). The thickest and most porous corrosion layers develop on fuel fragments exposed to the largest volumes of groundwater. Corrosion-layer compositions depend strongly on water …

A 120 GeV Main Injector proton beam will be delivered to the NuMI beam line at Fermilab at the rate of 3.7x 10{sup 20} per year. Realistic Monte Carlo simulations have been performed to examine the radiation environment in the beam extraction system and NuMI beam line elements. A complete 3-D model of the 160 meter extraction region has been implemented utilizing the computer code MARS. The model includes a description of the field of the electrostatic septa and POISSON calculated field maps of the Lambertson magnets and the other lattice components in the area. The beam element alignment and the source term have been simulated using the code STRUCT. Results on beam losses in the system, energy deposition in the core elements and residual dose rates on the components are presented.

We report the results of some recent E791 charm analyses. They include 1) a search for rare and forbidden decays, 2) measurements of form factors for D{sup +} {yields} K{sup *0}l{sup +}{nu}{sub l} and D{sup +}{sub s} {yields}{phi}l{sup +}{nu}{sub l}, and 3) D{sup +}{sub s} and D{sup 0} lifetime measurements including the lifetime difference between D{sup 0} {yields} K{sup -}{pi}{sup +} and D{sup 0} {yields} K{sup -}K{sup +}. The latter is the first direct search for a possible lifetime difference that could contribute to D{sup 0} - {anti D}{sup 0} mixing.

We discuss tau identification techniques at hadron colliders, and present the measurements and the searches performed so far. We report on top quark pair production in the decay channel containing at least one tau lepton. Also, we present results dedicated to searches for new particles, with taus in the final state. We present a search for the charged Higgs boson in the tau decay channel, as well as for the leptoquark family containing tau leptons. Finally, we indicate the capabilities of detecting and triggering on tau leptons in the future collider run.

We consider the s-channel R-parity-violating production of a single light top squark {tilde t}{sub 1} and its subsequent R-parity-conserving decay. For masses in the range 180-325 GeV, and R-parity-violating couplings {lambda}{sub 3ij}{double_prime} > 0.02-0.05, we show that discovery of the top squark is possible with 2 fb{sup {minus}1} of integrated luminosity at run II. If no evidence for the top squark is found, the bound on {lambda}{sub 3ij}{double_prime} can be reduced by up to an order of magnitude with existing data from run I, and by two orders of magnitude at run II.

Photoelectrons produced through the interaction of synchrotrons radiation and the vacuum chamber walls can be accelerated by a charged particle beam, acquiring sufficient energy to produce secondary electrons (SES) in collisions with the walls. If the secondary-electron yield (SEY) coefficient of the wall material is greater than one, a run-away condition can develop. In addition to the SEY, the degree of amplification depends on the beam intensity and temporal distribution. As the electron cloud builds up along a train of stored bunches, a transverse perturbation of the head bunch can be communicated to trailing bunches in a wakefield-like interaction with the cloud. The electron cloud effect is especially of concern for the high-intensity PEP-II (SLAC) and KEK B-factories and at the Large Hadron Collider (LHC) at CERN. An initiative was undertaken at the Advanced Photon Source (APS) storage ring to characterize the electron cloud in order to provide realistic limits on critical input parameters in the models and improve their predictive capabilities. An intensive research program was undertaken at CERN to address key issues relating to the LHC. After giving an overview, the recent theoretical and experimental results from the APS and the other laboratories will be discussed.

A total energy cycle analysis (TECA) of electric vehicles (EV) was recently completed. The EV energy cycle includes production and transport of fuels used in power plants to generate electricity, electricity generation, EV operation, and vehicle and battery manufacture. This paper summarizes the key assumptions and results of the EVTECA. The total energy requirements of EVS me estimated to be 24-35% lower than those of the conventional, gasoline-fueled vehicles they replace, while the reductions in total oil use are even greater: 55-85%. Greenhouse gases (GHG) are 24-37% lower with EVs. EVs reduce total emissions of several criteria air pollutants (VOC, CO, and NO{sub x}) but increase total emissions of others (SO{sub x}, TSP, and lead) over the total energy cycle. Regional emissions are generally reduced with EVs, except possibly SO{sub x}. The limitations of the EVTECA are discussed, and its results are compared with those of other evaluations of EVs. In general, many of the results (particularly the oil use, GHG, VOC, CO, SO{sub x}, and lead results) of the analysis are consistent with those of other evaluations.

A FEL of average power 200 kW is being designed at the LBNL for satellite power beaming. It utilizes the radiation of {approximately} 100 MeV electrons with {approximately} 200 A peak current. In order to obtain the desired peak current, the 5mm long electron bunches delivered by a linear accelerator are compressed to 1mm. Furthermore, it is important for the FEL operations that the compressed bunches have a uniform longitudinal density distribution over the entire bunch length. After the FEL, the electron beam is returned to the linear accelerator for deceleration. Since the electron beam acquires approximately 6% energy spread during radiation in the FEL, bunch de-compressor is used between the FEL and the linac to expand the electron bunches back to their original length and to reduce the energy spread. In this paper we present design and analysis of the bunch compressor and the bunch de-compressor that perform needed functions.

The CDF collaboration has adapted several heavy flavor tagging techniques and employed them in analyses of time-dependent flavor asymmetries using data from the Tevatron Run I. The tagging algorithms were calibrated using low-P{sub t} inclusive lepton and dilepton trigger data samples. The tagging techniques were applied to a sample of {approximately} 400 B{sub d}{sup 0}/{anti B}{sub d}{sup 0} {r_arrow} J/{psi}K{sub s}{sup 0} decays and were used to measure the CP violation parameter, sin(2{beta}). Prospects for future improved measurements of the CP violation parameters at the Tevatron are briefly discussed.

We present a report on recent measurements using the Advanced Photon Source at Argonne National Laboratory to explore the phenomenon of Nuclear Excitation by Electronic Transition (NEET) in the {sup 189}Os atomic/nuclear system.

The Overture framework is an object-oriented environment for solving partial differential equations in two and three space dimensions. It is a collection of C++ libraries that enables the use of finite difference and finite volume methods at a level that hides the details of the associated data structures. Overture can be used to solve problems in complicated, moving geometries using the method of overlapping grids. It has support for grid generation, difference operators, boundary conditions, data-base access and graphics. Short sample code segments are presented to show the power of this approach.