We present a novel technique for characterizing transverse beam dynamics using a dual-sweep streak camera. The camera is used to record the front view of successive beam bunches and/or successive turns of the bunches. This extension of the dual-sweep technique makes it possible to display non-repeatable beam transverse motion in two fast and slow time scales of choice, and in a single shot. We present a study of a transverse multi-bunch instability in the APS storage ring. The positions, sizes, and shapes of 20 bunches (2.84 ns apart) in the train, in 3 to 14 successive turns (3.68 {micro}s apart) are recorded in a single image, providing rich information about the unstable beam. These include the amplitude of the oscillation ({approximately}0.0 at the head of the train and {approximately}2 mm towards the end of the train), the bunch-to-bunch phase difference, and the significant transverse size growth within the train. In the second example, the technique is used to characterize the injection-kicker induced beam motion, in support of the planned storage ring top-up operation. By adjusting the time scale of the dual sweep, it clearly shows the amplitude ({+-}1.8mm) and direction of the kick, and the subsequent decoherence ({approximately} 500 turns) …

To facilitate airborne radioxenon monitoring, a xenon concentration method with potential advantages over current technology in simplicity, size, and cost has been developed. The concentration technique is based on the preferential absorption of heavy noble gases (krypton, xenon, and radon) by certain organic fluids. To implement this concentration technique, a radioxenon monitoring system requires three integrated sub-systems: (1) an absorption sub-system; (2) a degassing sub-system; and (3) a radiation detection sub-system. This study is focused on the characterization and optimization of the first two sub-systems. Measurements using a small prototype absorption tower have indicated a xenon removal factor of approximately 50% and the specific concentration at saturation of certain organic fluids to be about 2.5 times the specific concentration in the sampled air. Various techniques for degassing have been investigated, including heating, purging, agitation and vacuum. Ultrasonic agitation of a thin film in a strong vacuum has been shown to be an effective means of degassing the transfer fluid continuously. Various schemes for integrating all of the sub-systems are considered. Combining the small prototype absorption and degassing sub-systems should result in a transfer efficiency of about 33% and a single stage concentration factor of about 6.7.

The National Ignition Facility (NIF) is a U.S. Department of Energy (DOE) laser fusion experimental facility currently under construction at the Lawrence Livermore National Laboratory (LLNL). This paper describes the safety and environmental processes followed by NIF during the design and construction activities.

The National Ignition Facility (NIF) is a US Department of Energy inertial confinement laser fusion experimental facility currently under construction at the Lawrence Livermore National Laboratory (LLNL). To ensure that decontamination and decommissioning (D&D) issues at the end-of-life are manageable, this subject has received attention from an early stage. This paper summarizes the NIF D&D issues, and the status of the D&D plan.

The Digitizing Beam Position Limit Detector (DBPLD) is designed to identify and react to beam missteering conditions in the Advanced Photon Source (APS) storage ring. The high power of the insertion devices requires these missteering conditions to result in a beam abort in less than 2 milliseconds. Commercially available beam position monitors provide a voltage proportional to beam position immediately upstream and downstream of insertion devices. The DBPLD is a custom VME board that digitizes these voltages and interrupts the heartbeat of the APS machine protection system when the beam position exceeds its trip limits.

Selected optical diagnostics stations were upgraded in anticipation of low-emittance, bright electron beams from a thermionic rf gun or a photoelectric rf gun on the Advanced Photon Source (APS) injector linac. These upgrades include installation of optical transition radiation (OTR) screens, transport lines, and cameras for use in transverse beam size measurements and longitudinal profile measurements. Using beam from the standard thermionic gun, tests were done at 50 MeV and 400 to 650 MeV. Data were obtained on the limiting spatial ({sigma} {approximately} 200 {micro}m) and temporal resolution (300 ms) of the Chromox (Al{sub 2}O{sub 3} : Cr) screen (250-{micro}n thick) in comparison to the OTR screens. Both charge-coupled device (CCD) and charge-injection device (CID) video cameras were used as well as the Hamamatsu C5680 synchroscan streak camera operating at a vertical deflection rate of 119.0 MHz (the 24th subharmonic of the S-band 2856-MHz frequency). Beam transverse sizes as small as {sigma}{sub x} = 60 {micro}m for a 600-MeV beam and micropulse bunch lengths of {sigma}{sub {tau}}<3 ps have been recorded for macropulse-averaged behavior with charges of about 2 to 3 nC per macropulse. These techniques are applicable to linac-driven, fourth-generation light source R and D experiments including the APS's …

Particle-beam characterizations of a multi (7)-GeV storage ring beam have been done for the first time using a synchroscan and dual-sweep x-ray streak camera at the Advanced Photon Source (APS). The hard x-rays (2-20 keV) from a bending magnet source were imaged using an adjustable pinhole aperture, and both the horizontal size, {sigma}{sub x} {approximately} 190 {micro}m, and bunch length, {sigma}{sub t} {approximately} 28 ps, were measured simultaneously. The Au photocathode provides sensitivity from 10 eV to 10 keV covering the three orders of magnitude in wavelength from the UV to hard x-rays.

Expert Microsystems teamed with Argonne National Laboratory (ANL), a DOE contractor, to develop an innovative dynamics sensor validation system under a Small Business Technology Transfer (STTR) Phase I contract with NASA. The project improves launch vehicle mission safety and system dependability by enabling rapid development and cost effective maintenance of embeddable real-time software to reliably detect process-critical sensor failures. The project focused on verifying the feasibility of two innovative software methods developed by ANL to provide high fidelity sensor data validation for nuclear power generating stations, the Sequential Probability Ratio Test (SPRT) algorithm and the Multivariate State Estimation Technique (MSET) algorithm, as core elements of a commercial Dynamics Sensor Validation System (DSVS). The research verified that ANL algorithms enable highly reliable data validation for high frequency Space Shuttle Main Engine (SSME) dynamics sensors, such as accelerometers and strain gauges. Phase I culminated in production of a prototype run-time module which validates SSME flight accelerometer data with very high reliability. The resulting sensor validation development system is widely applicable to reusable launch vehicle (RLV) and ground support control and monitoring systems.

This paper will describe and analyze the rf beam position monitor (RFBPM) front-end upgrade for the Advanced Photon Source (APS) storage ring. This system is based on amplitude-to-phase (AM/PM) conversion monopulse receivers. The design and performance of the existing BPM front-end will be considered as the baseline design for the continuous effort to improve and upgrade the APS beam diagnostics. The upgrade involves redesigning the in-tunnel filter comparator units to improve insertion loss, return loss, and bandpass filter matching that presently limit the different fill patterns used at APS.

Ab initio molecular orbital calculations have been used to investigate the nature of lithium bonding in stage 1 lithium intercalated carbon anodes. This has been approximated by using layered carbon lattices such as coronene, (C{sub 24}H{sub 12}),anthracene, and anthracene substituted with boron. With two coronene carbon lattices forming a sandwich structure and intercalated with either 2, 3, 4 or 6 six lithiums, it has been found that the predominant mode of bonding for the lithium is at the carbon edge sites as opposed to bonding at interior carbon hexagon sites. Formation of all structures is thermodynamically allowed except for the two lithium case in which there is repulsion between the lattices. The optimized structure with six lithiums gives a reasonable approximation for the stage 1 lithium intercalated carbon anode. In this case the lithium to carbon ratio is 1:8 versus 1:6 occurring in the stage 1 graphite. The coronene lattices are eclipsed with a separation of 4.03 {angstrom}. However, there is a slight ruffling of the lattice. Separation between adjacent lithiums is either 3.32 {angstrom} or 2.98 {angstrom}. Even though the separation between lithiums is very small, composition of the molecular orbitals suggests that there is no lithium cluster formation. …

Configuration of four-button beam position monitors (BPMs) employed in small-gap beam chambers is optimized from 2-D electrostatic calculation of induced charges on the button electrodes. The calculation shows that for a narrow chamber of width/height (2w/2h) >> 1, over 90% of the induced charges are distributed within a distance of 2h from the charged beam position in the direction of the chamber width. The most efficient configuration for a four-button BPM is to have a button diameter of (2-2.5) h with no button offset from the beam. The button sensitivities in this case are maximized and have good linearity with respect to the beam positions in the horizontal and vertical directions. The button sensitivities and beam coefficients are also calculated for the 8-mm and 5-mm chambers used in the insertion device straight sections of the 7-GeV Advanced Photon Source.