Our understanding of the generation of coherent synchrotron radiation in magnetic bending systems and its impact on beam dynamics has grown considerably over the past few years. The search for understanding has brought a number of surprises, all related to the complexity of the fully self-consistent problem. Herein I survey the associated phenomenology, theory, and experiments while emphasizing important subtleties that have recently been uncovered. I conclude by speculating on courses of future investigations that may prove fruitful.

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One of the objectives of the U.S. Department of Defense is to standardize all classes used in object-oriented deployment simulations by developing a standard class attribute representation and behavior for all deployment simulations that rely on an underlying class representation. The EXtensive Hierarchy and Object Representation for Transportation Simulations (EXHORT) is a class framework composed of two hierarchies that together constitute a standard and consistent class attribute representation and behavior that could be used directly by a large set of deployment simulations. The first hierarchy, the Transportation Class Hierarchy (TCH), was submitted to the Army Modeling and Simulation Office's (AMSO) Army Standards Repository in 1999 and presented at the Fall Simulation Interoperability Workshop in the same year. The second hierarchy, the Infrastructure Class Hierarchy (ICH), describes the encapsulation of the rest of the defense transportation system and is the primary focus of this paper. The entire EXHORT framework lets deployment simulations use the same set of underlying class data, ensures transparent exchanges, reduces the effort needed to integrate simulations, and permits a detailed analysis of the defense transportation system.

A Monte Carlo procedure is used to generate N-particle configurations compatible with two-temperature canonical equilibria in two dimensions, with particular attention to nonlinear plasma gyrokinetics. An unusual feature of the problem is the importance of a nontrivial probability density function R0(PHI), the probability of realizing a set {Phi} of Fourier amplitudes associated with an ensemble of uniformly distributed, independent particles. This quantity arises because the equilibrium distribution is specified in terms of {Phi}, whereas the sampling procedure naturally produces particles states gamma; {Phi} and gamma are related via a gyrokinetic Poisson equation, highly nonlinear in its dependence on gamma. Expansion and asymptotic methods are used to calculate R0(PHI) analytically; excellent agreement is found between the large-N asymptotic result and a direct numerical calculation. The algorithm is tested by successfully generating a variety of states of both positive and negative temperature, including ones in which either the longest- or shortest-wavelength modes are excited to relatively very large amplitudes.

Natural gas transmission companies mark the right-of-way areas where pipelines are buried with warning signs to prevent accidental third-party damage. Nevertheless, pipelines are sometimes damaged by third-party construction equipment. A single incident can be devastating, causing death and millions of dollars of property loss. This damage would be prevented if potentially hazardous construction equipment could be detected, identified, and an alert given before the pipeline was damaged. The Gas Technology Institute (GTI) is developing a system to solve this problem by using an optical fiber as a distributed sensor and interrogating the fiber with an custom optical time domain reflectometer. Key issues are the ability to detect encroachment and the ability to discriminate among potentially hazardous and benign encroachments. The work performed in the third quarter of the project (2nd quarter of 2002) includes design of the diode laser driver and high-speed detector electronics and programming of the custom optical time domain reflectometer.

The Interstate Clean Transportation (ICTC) purpose is to develop a public-private partnership dedicated to accelerating the market penetration of clean, alternative fuel vehicles (AFVs) in interstate goods movement. In order to foster project development, the ICTC activity sought to increase awareness of heavy-duty AFVs among truck fleet operators.

Polycrystals of the intermetallic compound of the Dy{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} system, where x = 0, 0.25, 0.5, 0.625, 0.675, 0.725, 0.75, 0.775, 0.825, 0.875, and 1, have been prepared by electric-arc-melting on water-cooled copper hearth in an argon atmosphere. A study of phase relationships and crystallography in the pseudobinary system Dy{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} using X-ray powder diffraction data and optical metallography was completed. It revealed that silicides in the composition range from 0.825 to 1 crystallize in the Gd{sub 5}Si{sub 4}-type crystal structure: germanides in the composition range from 0 to 0.625 crystallize in the Sm{sub 5}Ge{sub 4}-type structure, and alloys with intermediate composition range from 0.675 to 0.775 crystallize in the monoclinic Gd{sub 5}Si{sub 2}Ge{sub 2}-type structure. The -{Delta}S{sub m} values were determined from magnetization measurements for 7 alloys. The alloys with a monoclinic crystal structure which belong to an intermediate phase region have large MCE value, which exceeds those observed in the other two phase regions by 300 to 500%. The nature of the observed magnetic and structural transformations in the Dy{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} system seems to be similar with those reported for the Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} system. However, the …

Using the ion channeling techniques we find that a substantial fraction (up to 15%) of the Mn atoms reside in interstitial sites in Ga{sub 1-x}Mn{sub x}As alloys (with x ranging from 0.02 to 0.09). Moreover, the T{sub C} of Ga{sub 1-x}Mn{sub x}As is found to be very sensitive to annealing at temperatures close to the growth temperature of 265 C. Ion channeling results demonstrate that the increase of TC after annealing at 282 C can be attributed to a relocation of Mn atoms from interstitial sites to form random clusters. A series of Ga{sub 1-x-y}Mn{sub x}Be{sub y}As layers, in which the magnetic moments and free holes are independently controlled by the Mn and Be contents, respectively, are also investigated. A dramatic increase of the concentration of Mn interstitials and a reduction of T{sub C} are observed as the Be concentration increases, while the free hole concentration stays relatively constant at {approx}5x10{sup 20}cm{sup -3}. These results demonstrate that the concentrations of free holes as well as uncompensated Mn spins are governed by the position of the Fermi level, which controls the formation energy of compensating interstitial Mn acceptors. This Fermi-level-induced hole saturation is responsible for the commonly observed upper limit of …

An x-ray streak camera operating in accumulation mode was developed for studying ultrafast dynamics at synchrotron facilities. A laser-triggered photoconductive switch was used as a sweeping unit to obtain low timing jitter. The fast rise time of the ramp pulse generated by the switch (90 ps) combined with the fast response of the traveling wave deflection plates (150 ps) significantly reduced the jitter caused by the shot-to-shot laser fluctuation. At {approx}1% rms (root mean square) laser energy fluctuation, the resolution of the camera is 1.1 ps when over 5000 laser shots were accumulated. This is two times better than that of the previous design with slower response (300 ps) deflection plates.

This paper introduces two efficient algorithms that compute the Contour Tree of a 3D scalar field F and its augmented version with the Betti numbers of each isosurface. The Contour Tree is a fundamental data structure in scientific visualization that is used to pre-process the domain mesh to allow optimal computation of isosurfaces with minimal storage overhead. The Contour Tree can be also used to build user interfaces reporting the complete topological characterization of a scalar field, as shown in Figure 1. In the first part of the paper we present a new scheme that augments the Contour Tree with the Betti numbers of each isocontour in linear time. We show how to extend the scheme introduced in 3 with the Betti number computation without increasing its complexity. Thus we improve on the time complexity from our previous approach 8 from 0(m log m) to 0(n log n+m), where m is the number of tetrahedra and n is the number of vertices in the domain of F. In the second part of the paper we introduce a new divide and conquer algorithm that computes the Augmented Contour Tree for scalar fields defined on rectilinear grids. The central part of the …

As a first step towards developing liquid lithium target technology for a future high-power nuclear physics fragmentation facility, an adjustable thickness Li/Be hybrid target is being constructed for use at the NSCL. This target will use beryllium windows with flowing lithium. The lithium serves as a part of the target as well as the coolant. Up to 1 kW of beam power is dissipated in the target and is carried away by the recirculating liquid lithium loop. It is designed for high power beams in the mass range from oxygen to calcium. Tapered beryllium windows combined with a uniform thickness lithium channel gives an overall target thickness ranging from 0.7 g/cm{sup 2} to 3 g/cm{sup 2}, which is adjusted by moving the target vertically. The target system design is complete and is described in this paper.

This fourth quarterly technical report discusses the progress made on a machine vision technique for determining coal content and ore grades. Work done this quarter has been primarily devoted to improving the apparatus and data collection system. This includes a totally new optical setup, continued development of a new imaging spectrometer, and software improvements. Additionally, interest from other mining operations has arisen and sample of titanium and talc have now been obtained for preliminary analysis. Work is ongoing with coal samples, although it appears a more diverse sampling may be required. With the improvements now being made in the system, much faster and more user-friendly data collection and analysis will result in faster and better turn-around for sample analysis.