The design and construction of an all copper S-band one-and-half cell photocathode electron gun without a choke joint is described. The methods utilized to determine the field balance at the operational frequency without usage of the bead pulling perturbation measurement is given together wit the computational data.

The Met Lab Carolina Bay is subject to Subtitle C of RCRA and CERCLA requirements. Located in the northwestern section of the Savannah River Site, the Met Lab Carolina Bay is a marshy, oval-shaped natural depression covering approximately six acres. The Carolina Bay received wastes from three sources: the Met Lab Basin A-007 drainage outfall, the A-Area coal-fire power plant A-008 drainage outfall and the A/M-Area vehicle maintenance parking lot stormwater runoff A-009 outfall. Two characterization efforts conducted in 1988/89 and 1991 indicate the presence of metals in the sediments and soils of the bay. The greatest concentrations of the metals and organics being in the north-central portion of the bay. The metals and organics were primarily associated with surface sediments and the organic-rich soil layer to a depth of about two feet. Conclusions from the Human Health Baseline Risk indicate the future on-unit resident exposure to sediments and soil poses an unacceptable level of risk to human health. However, the assumptions built into the calculations lead to conservative human health risk findings. A qualitative Ecological Risk Assessment was performed on the Carolina Bay. This ecological assessment, based on historical and existing sampling data, was found to be insufficient to …

One of the central problems in nuclear physics is the description of nuclei as systems of nucleons interacting via realistic potentials. There are two main aspects of this problem: (1) specification of the Hamiltonian, and (2) calculation of the ground (or excited) states of nuclei with the given interaction. Realistic interactions must contain both two- and three-nucleon potentials and these potentials have a complicated non-central operator structure consisting, for example, of spin, isospin and tensor dependencies. This structure results in formidable many-body problems in the computation of the ground states of nuclei. At Argonne and Urbana, the authors have been following a program of developing realistic NN and NNN interactions and the methods necessary to compute nuclear properties from variational wave functions suitable for these interactions. The wave functions are used to compute energies, density distributions, charge form factors, structure functions, momentum distributions, etc. Most recently they have set up a collaboration with S. Boffi and M. Raduci (University of Pavia) to compute (e,e{prime}p) reactions.

A preconceptual design for an Accelerator Production of Tritium (APT) facility is currently under development by several national laboratories in conjunction with industry. The design consists of an accelerator that bombards a spallation target with high energy protons. Neutrons are produced in the spallation target and are absorbed in a blanket material to produce tritium. Two spallation targets are currently under investigation: (1) a tungsten neutron source target and (2) a lead neutron source target. In the tungsten target the neutrons are captured in helium-3, which is circulated through the system, thus producing tritium. The lead target is surrounded with a lithium-aluminum blanket and the tritium is produced in the lithium-6. The investigation of possible radiological impacts on the public is being performed as a part of the safety evaluations of the preconceptual design. These studies include the estimation of releases of radioactive materials from the two spallation targets and the possible impacts on the public.

NonDestructive Testing (NDT) is commonly used to monitor structures before, during and after testing. This paper reports on the use of two NDT techniques to monitor the behavior of a typical wind turbine blade during a quasi-static test-to-failure. The test used a three-point spanwise load distribution to load a 7.9-m blade to failure. The two NDT techniques used were acoustic emission and coherent optical. The former monitors the acoustic energy produced by the blade as it is loaded. The latter uses electronic shearography to measure the differences in surface displacements between two load states with an accuracy of a few microns. Typical results are presented to demonstrate the ability of these two techniques to locate and monitor both high damage regions and flaws in the blade structure. Further, this experiment highlights the limitations in the techniques that must be addressed before one or both can be transferred, with a high probability of success, to the inspection and monitoring of turbine blades during the manufacturing process and under normal operating conditions.

An oxygen deficiency exists when the concentration of oxygen, by volume, drops to a level at which atmosphere supplying respiratory protection must be provided. Since liquid cryogens can expand by factors of 700 (LN{sub 2}) to 850 (LH{sub e}), the uncontrolled release into an enclosed space can easily cause an oxygen-deficient condition. An oxygen deficiency hazard (ODH) fatality rate per hour ({O}) is defined as: {O} = {Sigma} N{sub i}P{sub i}F{sub i}, where N{sub i} = number of components, P{sub i} =probability of failure or operator error, and F{sub i} - fatality factor. ODHs range from ``unclassified`` ({O}<10{sup {minus}9} 1/h) to class 4, which is the most hazardous ({O}>10{sup {minus}1} 1/h). For Superconducting Super Collider Laboratory (SSCL) buildings where cryogenic systems exist, failure rate, fatality factor, reduced oxygen ratio, and fresh air circulation are examined.

The modulators used in the Advanced Photon Source at Argonne National Laboratory have been redesigned with an emphasis on electrical noise reduction. Since the modulators are 100 MW modulators with <700 ns rise time, electrical noise can be coupled very easily to other electronic equipment in the area. This paper will detail the effort made to reduce noise coupled to surrounding equipment. Shielding and sound grounding techniques accomplished the goal of drastically reducing the noise induced in surrounding equipment. The approach used in grounding and shielding will be discussed, and data will be presented comparing earlier designs to the improved design.

Low-Q diffractometers at spallation sources that use time of flight methods have been successfully implemented at several facilities, including the Los Alamos Neutron Scattering Center. The proposal to build new, more powerful, advanced spallation sources using advanced moderator concepts will provide luminosity greater than 20 times the brightest spallation source available today. These developments provide opportunity and challenge to expand the capabilities of present instruments with new designs. The authors review the use of time of flight for low-Q measurements and introduce new designs to extend the capabilities of present-day instruments. They introduce Monte Carlo methods to optimize design and simulate the performance of these instruments. The expected performance of the new instruments are compared to present day pulsed source- and reactor-based small-angle neutron scattering instruments. They review some of the new developments that will be needed to use the power of brighter sources effectively.

Sandia National Laboratories (SNL) has shown that an automated personnel tracking and material monitoring system enhances protection of sensitive and classified parts against an insider. Such a system also significantly reduces the number of required, manual physical inventories at Department of Energy (DOE) sites while increasing assurance that material has not been diverted. SNL`s Insider Technology Department developed and is enhancing its generic, real-time, personnel tracking and material monitoring system. The system consists of facility selectable modules. This paper presents an overview of the modules, evaluation results, user`s suggestions, and future modules.

High critical currents have been obtained in Bi-Sr-Ca-Cu-O by the powder-in-tube approach. Owing to the inherent structural anisotropy of the Bi-based high-Tc superconducting materials, high-Jc is only obtained when the wires are subsequently rolled into rectangularly cross-sectioned tapes. Previously, intermediate annealing was employed to maintain ductility in the silver with a high temperature sintering just before the final rolling in order to form the high-Tc superconducting phase. Here, the authors report on the effects of hot-rolling at various temperatures for the final rolling of powder-in-tube BSCCO-2212 tapes. Hot-rolling was accomplished by preheating the rolls with infrared heaters and rolling the tapes directly from the furnace. The highest current densities were obtained by final hot-rolling the 2212 tapes at 420{degrees}C with the furnace temperature of 750{degrees}C, the highest temperature studied. Results showed the enhancement of Jc was due to the improvement of grain alignment as well as the reduction of the size and fraction of Bi-free phases during the final heat treatment. Furthermore, an analytical model of the hot-rolling process has been developed that illustrates the importance of preheating the tapes and heating the rolls.

At the Savannah River Site (SRS), several facilities have nearly all their special nuclear material in solution and therefore, volume measurements play a key role in the accountability of these materials. Normally, facilities rely on frequent instrument calibrations, periodic tank calibrations and proper instrument configuration to ensure measurement control. At SRS, methods have been employed that go beyond these basic steps to monitor the volume measurement systems and provide real time indication of measurement control. These methods can be used to indicate if a tank requires recalibration, if there is a sampling problem, or if there is an instrument problem. The methods include: sample density comparison, in-tank to laboratory density comparison, redundant instrument comparison and tank to tank transfer comparison. This paper describes these methods and the generation of control charts to track these comparisons in real time.

A Monte-Carlo simulation of Compton backscattered {kappa}{sub L}=3.2-{mu}m photons from an IR-FEL on 75-MeV electrons in a storage ring yields an RMS electron energy spread of {Delta}{sub E}=11.9-keV for a sample of 10{sup 7} single scattering events. Electrons are sampled from a beam of natural energy spread {sigma}{sub E} = 5.6-keV and damped transverse angle spreads {sigma}{sub x}{prime}, = .041-mrad and {sigma}{sub y}{prime} = .052-mrad (100%) coupling, scaled from the 200-MeV BNL XLS compact storage ring. The Compton-scattered X-Rays are generated from an integral of the CM Klein-Nishina cross-section transformed to the lab. A tracking calculation has also been performed in 6-dimensional phase space. Initial electron coordinates are selected randomly from a Gaussian distribution of RMS spreads {sigma}{sub xo}=.102-mm, {sigma}{sub x{prime}o}=.041-mrad, {sigma}{sub yo}=.018-mm, {sigma}{sub y{prime}o}=.052-mrad, {sigma}{sub {phi}o}=22-mrad and {sigma}{sub Eo}=6-keV. A sample of 10000 electrons were each following for 40000 turns around the ring through an RF cavity of f{sub rf}=211.54-MHz and peak voltage V{sub m}=300-keV. Preliminary results indicate that the resulting energy distribution is quite broad with an RMS width of {Delta}{sub E} = 124-keV. The transverse widths are only slightly increased from their original values, i.e. {Delta}{sub x} = .106-mm and {Delta}{sub x}{prime}=.043 mrad. The scaled energy spread …

The booster at the NSLS is being upgraded from 0.75 to 2 pulses per second. To accomplish this, new power supplied for the dipole, quadrupole, and sextupole have been installed. This paper will outline the design and function of the digital signal processor used as the primary control element in the power supply control system.

Coaxial dampers with E-probe and H-loop couplers are used to damp higher-order mode (HOM) in an 840-MHz cylindrical prototype cavity. The dampers are positioned to have minimum coupling at the fundamental frequency, f{sub 0}, without using any blocking circuit. The E-probe dampers are used at the equatorial plane of the cavity. The H-loop dampers are used in the end wall of the cavity. The fundamental mode decoupling can be done by positioning the loop plane in the direction of the H-field of the mode. For both dampers, the fundamental mode coupling can be better than {minus}50 dB. The damper load resistance is varied to find the optimum loading. Measurement is made for three cases with (1) three E-probe dampers, (2) three H-loop dampers, and (3) three E-probe and three H-loop dampers.

Free surfaces, multicomponent phase change, volume expansion and compression, and surface tension gradients make for challenging application of the finite element method to sol-gel (ceramic) film and fiber formation. The microstructure of the final product is largely controlled by the competition between the drying, curing, and underlying fluid mechanics of formation. Sol-gel materials are peculiar because they often contain more than one solvent, each solvent differing in volatility and surface tension. Hence, nonuniform evaporation can produce surface tension gradients that dramatically change the meniscus shape. These processes are complicated further by a volume change that accompanies evaporation and condensation, making for shock-like discontinuities in concentration and velocity at the free surface. Computer-aided predictions of film formation by dip coating and of fiber spinning (see Figure 1) are made for alcohol-water mixtures with one non-volatile species. The Navier-Stokes system is augmented with two convective-diffusion equations to track the concentration of alcohol and water, and an energy equation to monitor temperature changes. The equations are solved in both phases by discretizing them first with the Galerkin/finite element method. The resulting non-linear algebraic equation set is solved with Newton`s method. The subdomaining technique is based on elliptic grid generation and is designed to …

The rf impedance of the isolation valve of the APS storage ring system was measured by the wire method with a synthetic pulse technique. The coupling impedance as well as the energy loss of the sector valve with and without an rf liner or screen, and the flange gap of the various sizes was measured. There appear to be resonances at certain frequencies without an rf liner that might cause an unacceptably large coupling impedance. Data with various sizes of the flange gap show that good rf contact around any flange is necessary. The impedance due to intrusions into the beam chamber was also measured. The results are compared with the computer simulation from MAFIA.

In Photo-Injectors (PI) electron guns, electrons are emitted from a photocathode by a short laser pulse and then accelerated by intense rf fields in a resonant cavity. The best known advantage of this technique is the high peak current with a good emittance (high brightness). This is important for short wavelength Free-Electron Lasers and linear colliders. PIs are in operation in many electron accelerator facilities and a large number of new guns are under construction. Some applications have emerged, providing, for example, very high pulse charges. PIs have been operated over a wide range of frequencies, from 144 to 3000 MHz (a 17 GHz gun is being developed). An exciting new possibility is the development of superconducting PIs. A significant body of experimental and theoretical work exists by now, indicating the criticality of the accelerator elements that follow the gun for the preservation of the PI`s performance as well as possible avenues of improvements in brightness. Considerable research is being done on the laser and photocathode material of the PI, and improvement is expected in this area.

In order to overcome range limitations, the existing Beam Position Monitor (BPM) receiver was modified, extending the dynamic range from 35 dB to 60 dB. The modifications include the insertion of an RF PIN attenuator, RF amplifier, and control circuitry in line with the RF link to add an extra 25dB to the existing AGC loop. This stand alone 25dB RF gain control stage is integrated into the present system without any change to the existing receiver.

Recent economic and environmental issues have stimulated interest in solder alloys other than the traditional Sn-Pb eutectic or near eutectic composition. Preliminary evaluations suggest that several of these alloys approach the baseline properties (wetting, mechanical, thermal, and electrical) of the Sn-Pb solders. Final alloy acceptance will require major revisions to existing industrial and military soldering specifications. Bulk alloy and solder joint properties are consequently being investigated to validate their producibility and reliability. The work reported in this paper examines the wetting behavior of several of the more promising commercial alloys on copper substrates. Solder wettability was determined by the meniscometer and wetting balance techniques. The wetting results suggest that several of the alternative solders would satisfy pretinning and surface mount soldering applications. Their use on plated through hole technology might be more difficult since the alloys generally did not spread or flow as well as the 60Sn-40Pb solder.

A two-stage light-gas gun has been used to impact thin zinc bumpers by zinc projectiles over the velocity range of 2.4 km/s to 6.7 km/s to determine the propagation characteristics of the impact generated debris. Constant-mass projectiles in the form of spheres, discs, cylinders and rods were used in these studies. Radiographic techniques were employed to record the debris cloud generated upon impact and the dynamic formation of the resulting rupture in an aluminum backing plate resulting from the loading of the debris cloud. The characteristics of the debris cloud generated upon impact is found to depend on the projectile shape. The data indicate that the debris front velocity is independent of the shape of the projectile, whereas the debris lateral/radial velocity is strongly dependent on projectile geometry. Spherical impactors generate the most radially dispersed debris cloud while the normal plate impactors result in column-like debris. It has been observed that the debris generated by the impact of thin plates on a thin bumper shield is considerably more damaging to a backwall than the debris generated by an equivalent-mass sphere.

Following a discussion of some physics issues in {eta} experiments, the current status of the ({pi},{eta}) experiments is reviewed. Future prospects for {eta} experiments are also presented.

The physical state of a debris cloud generated upon impact of a thin flier plate with a thin bumper depends on the impact velocity. At impact velocities of 10km/s, the debris cloud is expected to be primarily molten with some vapor present. A series of calculations using the finite-difference code CTH has been used to evaluate the effect of phase change (i.e., higher concentrations of vapor) in debris clouds and their subsequent impact on a backwall structure. In these calculations, the higher concentrations of vapor is achieved by increasing the initial temperature of the impactor and the bumper material while keeping the same impact velocity. The nature of the interaction of the debris cloud and the subsequent loading on the backwall depends on its thermophysical state. This interaction (with a backwall) can cause either spallation, rupture, or simply bulging of the backwall structure. These results will be discussed and compared with an impact experiment performed at {approximately}10km/s on the Sandia hypervelocity launcher. In the experiment, the debris cloud was generated by the impact of a titanium plate with a titanium bumper.

X-ray topography and rocking curve experiments were performed on {alpha}-mercuric iodide samples. As-grown crystals were examined for Intrinsic defects and crystallinity. Orientation of certain defects depends on the direction of crystal growth. The propagation of as-grown crystalline features was documented. The extent of crystal damage Introduced during various steps of device fabrication such as sawing, polishing, etching and contact deposition was explored. Coefficients of linear thermal expansion of {alpha}{sub 33} = 54 {plus_minus} 5{center_dot}10{sup {minus}6}/{degrees}C along the tetragonal c-axis, [001] direction and {alpha}{sub 11} = 11 {plus_minus} 4{center_dot}10{sup {minus}6}/{degrees}C in the [100] direction were measured.

This paper describes the sensitivity and offset calibration for the beam position monitors (BPMs) using button-type pickups in the injector synchrotron, storage ring, and insertion devices of the Advanced Photon Source (APS). In order to reduce the overall offset and to isolate the error ({approx_lt} 100 {mu}m) due to the low fabrication tolerance in the extruded storage ring vacuum chamber, the electrical offset is minimized by carefully sorting and matching the buttons and cables according to the button capacitance and the characteristic impedances of the cable and the button feedthrough. The wire method is used for the sensitivity calibration, position-to-signal mapping, and measurement of resolution and long-term drift ({approx_lt} 1 mV) of the processing electronics. The processing electrons was also tested at Stanford Synchrotron Radiation Laboratory (SSRL) using a real beam, with results indicating better than 25 {mu}m resolution for the APS storage ring. Conversion between the BPM signal and the actual beam position is done by using polynomial expansions fit to the mapping data with absolute accuracy better than 25 {mu}m within {plus_minus}5 mm square. Measurement of the effect of button mispositioning and mechanical inaccuracy of the extruded storage ring vacuum chamber, including deformation under vacuum, will be also …