The communications technology satellite and the associated ground terminals for experiments

General spacecraft operational characteristics of the Communications Technology Satellite are discussed with particular emphasis on communication system parameters. Associated used ground terminals are reviewed. Wideband communications are also discussed

Control System for the LEDA 6.7-MeV Proton Beam Halo Experiment

Measurement of high-power proton beam-halo formation is the ongoing scientific experiment for the Low Energy Demonstration Accelerator (LEDA) facility. To attain this measurement goal, a 52-magnet beam line containing several types of beam diagnostic instrumentation is being installed. The Experimental Physics and Industrial Control System (EPICS) and commercial software applications are presently being integrated to provide a real-time, synchronous data acquisition and control system. This system is comprised of magnet control, vacuum control, motor control, data acquisition, and data analysis. Unique requirements led to the development and integration of customized software and hardware. EPICS real-time databases, Interactive Data Language (IDL) programs, LabVIEW Virtual Instruments (VI), and State Notation Language (SNL) sequences are hosted on VXI, PC, and UNIX-based platforms which interact using the EPICS Channel Access (CA) communication protocol. Acquisition and control hardware technology ranges from DSP-based diagnostic instrumentation to the PLC-controlled vacuum system. This paper describes the control system hardware and software design, and implementation.Comment: LINAC2000 Conference, 4 pg

Branching Transition of a Directed Polymer in Random Medium

A directed polymer is allowed to branch, with configurations determined by global energy optimization and disorder. A finite size scaling analysis in 2D shows that, if disorder makes branching more and more favorable, a critical transition occurs from the linear scaling regime first studied by Huse and Henley [Phys. Rev. Lett. 54, 2708 (1985)] to a fully branched, compact one. At criticality clear evidence is obtained that the polymer branches at all scales with dimension ${\bar d}_c$ and roughness exponent $\zeta_c$ satisfying $({\bar d}_c-1)/\zeta_c = 0.13\pm 0.01$, and energy fluctuation exponent $\omega_c=0.26 \pm0.02$, in terms of longitudinal distanceComment: REVTEX, 4 pages, 3 encapsulated eps figure

Inclusive versus Exclusive EM Processes in Relativistic Nuclear Systems

Connections are explored between exclusive and inclusive electron scattering within the framework of the relativistic plane-wave impulse approximation, beginning with an analysis of the model-independent kinematical constraints to be found in the missing energy--missing momentum plane. From the interplay between these constraints and the spectral function basic features of the exclusive and inclusive nuclear responses are seen to arise. In particular, the responses of the relativistic Fermi gas and of a specific hybrid model with confined nucleons in the initial state are compared in this work. As expected, the exclusive responses are significantly different in the two models, whereas the inclusive ones are rather similar. By extending previous work on the relativistic Fermi gas, a reduced response is introduced for the hybrid model such that it fulfills the Coulomb and the higher-power energy-weighted sum rules. While incorporating specific classes of off-shellness for the struck nucleons, it is found that the reducing factor required is largely model-independent and, as such, yields a reduced response that is useful for extracting the Coulomb sum rule from experimental data. Finally, guided by the difference between the energy-weighted sum rules of the two models, a version of the relativistic Fermi gas is devised which has the 0$^{\rm th}$, 1$^{\rm st}$ and 2$^{\rm nd}$ moments of the charge response which agree rather well with those of the hybrid model: this version thus incorporates {\em a priori} the binding and confinement effects of the stuck nucleons while retaining the simplicity of the original Fermi gas.Comment: LaTex file with 15 .ps figure

COMPETITIVE GRANTS AND THE FUNDING OF AGRICULTURAL RESEARCH IN THE U.S.

To increase the efficiency of the public agricultural R&D system, expanded use of competitive grants to fund state institutions has been advocated. This paper characterizes different funding instruments and empirically assesses the effects of changes in mechanism use. Factors associated with greater levels of competitive grants are modeled.Research and Development/Tech Change/Emerging Technologies,

The Arecibo L-band Feed Array Zone of Avoidance Survey I: Precursor Observations through the Inner and Outer Galaxy

The Arecibo L-band Feed Array (ALFA) is being used to conduct a low-Galactic latitude survey, to map the distribution of galaxies and large-scale structures behind the Milky Way through detection of galaxies' neutral hydrogen (HI) 21-cm emission. This Zone of Avoidance (ZOA) survey finds new HI galaxies which lie hidden behind the Milky Way, and also provides redshifts for partially-obscured galaxies known at other wavelengths. Before the commencement of the full survey, two low-latitude precursor regions were observed, totalling 138 square degrees, with 72 HI galaxies detected. Detections through the inner Galaxy generally have no cataloged counterparts in any other waveband, due to the heavy extinction and stellar confusion. Detections through the outer Galaxy are more likely to have 2MASS counterparts. We present the results of these precursor observations, including a catalog of the detected galaxies, with their HI parameters. The survey sensitivity is well described by a flux- and linewidth-dependent signal-to-noise ratio of 6.5. ALFA ZOA galaxies which also have HI measurements in the literature show good agreement between our measurements and previous work. The inner Galaxy precursor region was chosen to overlap the HI Parkes Zone of Avoidance Survey so ALFA performance could be quickly assessed. The outer Galaxy precursor region lies north of the Parkes sky. Low-latitude large-scale structure in this region is revealed, including an overdensity of galaxies near l = 183 deg and between 5000 - 6000 km/s in the ZOA. The full ALFA ZOA survey will be conducted in two phases: a shallow survey using the observing techniques of the precursor observations, and also a deep phase with much longer integration time, with thousands of galaxies predicted for the final catalog.Comment: 26 pages, 7 figures, 2 tables, Astronomical Journal accepte

Electron Spin Precession at CEBAF

The nuclear physics experiments at the Thomas Jefferson National Accelerator Facility often require longitudinally polarized electrons to be simultaneously delivered to three experimental halls. The degree of longitudinal polarization to each hall varies as function of the accelerator settings, making it challenging in certain situations to deliver a high degree of longitudinal polarization to all the halls simultaneously. Normally, the degree of longitudinal polarization the halls receive is optimized by changing the initial spin direction at the beginning of the machine with a Wien filter. Herein, it is shown that it is possible to further improve the degree of longitudinal polarization for multiple experimental halls by redistributing the energy gain of the CEBAF linacs while keeping the total energy gain fixed.Comment: 4 pages, 3 figures, to appear in the proceedings of the 18th International Symposium on Spin Physics (SPIN2008

Electronic Structures of Nitridomanganese(V) Complexes

The single-crystal polarized absorption and circular dichroism spectra of the nitridomanganese(V) complexes (salen)Mn⋮N (1), (1S,2S-(−)-saldpen)Mn⋮N (2), and (1R,2R-(+)-saldpen)Mn⋮N (3) have been measured [salen = N,N‘-ethylenebis(salicylideneaminato) dianion, 1S,2S-(−)-saldpen = N,N‘-(1S,2S-(−)-diphenyl)ethylenebis(salicylideneaminato) dianion, and 1R,2R-(+)-saldpen = N,N‘-(1R,2R-(+)-diphenyl)ethylenebis(salicylideneaminato) dianion]. As revealed by X-ray crystal structure analyses, these molecules have a distorted square-pyramidal geometry with a short Mn⋮N bond distance (1.52(3) Å for 2). The Cs compounds have a low-spin^ 1A‘[a‘(x^2 − y^2)]^2 ground state. The lowest absorption system (∼600 nm) consists of two components that are separated by approximately 4000 cm^(-1); these are assigned to ^1A‘ → ^1A‘[a‘(x^2 − y^2)a‘(yz)] (14 900 cm^(-1)) and ^1A‘ → ^1A‘‘[a‘(x^2 − y^2)a‘‘(xz)] (18 900 cm^(-1)) transitions