This paper describes the design and fabrication of a vacuum pumping system for the ATP/LEDA (Low Energy Demonstration Accelerator) RFQ (Radio Frequency Quadrupole) linac. Resulted from the lost proton beam, gas streaming from the LEBT (Low Energy Beam Transport) and out-gassing from the surfaces of the RFQ cavity and vacuum plumbing, the total gas load will be on the order of 7.2 x 10{sup -4} Torr-liters/sec, consisting mainly of hydrogen. The system is designed to pump on a continual basis with redundancy to ensure that the minimal operating vacuum level of 1 x 10{sup -6} Torr is maintained even under abnormal conditions. Details of the design, performance analysis and the preliminary test results of the cryogenic pumps are presented.

Newsletter of the Texas Department of Health discussing the news, activities, and events of the organization and other information related to health in Texas.

Hanford Site operators combine gamma ray isotopic and calorimetry measurements for nondestructive plutonium assay. Such measurements offer lower variability (particularly for heterogeneous materials) and decreased radiation exposure, cost, waste, intrusiveness, and material handling compared to destructive analysis. Until now, the International Atomic Energy Agency (IAEA) has relied on destructive analysis to perform the most accurate verification requirements for plutonium stored under safeguards at the Hanford Site. It was recognized that using calorimetry could significantly reduce the need for the IAEA to perform destructive analysis. To authorize the operator`s calorimeters for routine IAEA use, however, it was necessary to develop authentication features and perform independent 1558 testing. Authentication features include IAEA control of the hardware and calorimeter operating system software, measurement of certified IAEA standards, sealing of calorimeter chambers, and limited destructive analysis of IAEA selected items. A field test of these authentication features was performed at the Hanford Site in June 1997. The field test also was meant to enhance the credibility the IAEA imputes to calorimetry prior to its implementation. Progress in shared use of the Hanford Site calorimeters is reported.

The evolution of decomposition and succeeding primary crystallization in the bulk amorphous Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} alloy have been studied by small angle neutron scattering. Samples annealed isothermally in the supercooled liquid and in the solid state exhibit correlation peaks indicating quasiperiodic inhomogeneities in the scattering length density. The peak positions vary as a function of temperature as predicted by the linear Cahn-Hilliard theory of spinodal decomposition. Variations of the Be-Ti composition ratio of the alloy leads to significant changes in scattering signals. The initially homogeneous alloy separates into two amorphous phases. In the decomposed regions, crystallization probability increases leading to polymorphic crystallization.

The aggregation of di(2ethylhexyl) methane-, ethane- and butanediphosphonic acids and their complexes with various metal cations at different concentrations in toluene has been studied in detail using Small Angle Neutron Scattering. The diphosphonic acids are being employed as novel solvent extraction reagents in the Chemistry Division of ANL. These compounds exhibit extraordinarily strong affinity for actinide ions and for Fe(III). The growth of large metal-diphosphonate aggregates depends on the metal species, metal to extractant ratio, and the length of the carbon bridge between the two acid groups. Fe(III) complexes with the methane and butane (but not the ethane) bridged diphosphonic acid aggregate to form large polymeric rods at high metal to extractant ratios. Actinide ions likewise give large aggregates with di(2ethylhexyl) methanediphosphonic acid. Ca{sup 2+} and La{sup 3+} show only the usual formation of small `monomeric` chelates.

Ultrashort laser pulse ablation removes material with low energy fluence required and minimal collateral damage. The ultimate usefulness of this technology for biomedical applications depends, in part, on characterization of the physical conditions attained and determination of the zone of shockwave and heat affected material in particular tissues. Detailed numerical modeling of the relevant physics (deposition, plasma formation, shockwave generation and propagation, thermal conduction) are providing this information. A wide range of time scales is involved, ranging from picosecond for energy deposition and peak pressure and temperature, to nanosecond for development of shockwave, to microsecond for macroscopic thermophysical response.

Most research on polymer degradation is for single polymers, even though the thermal decomposition of polymer mixtures is of interest both practically and theoretically. Polymer degradation rates depend on the mixture type, and adding a polymer can increase, decrease, or leave unchanged the degradation rate of the first polymer. We show how distribution-kinetics theory, based on molecular-weight distributions (MWDs), provides expressions for degradation rates of binary polymer mixtures. The approach accounts for initiation, termination, hydrogen abstraction, and radical chain scission in the governing equations for MWDS. Molecular-weight moments yield expressions for molar and mass concentrations and rate coefficients for combinations of random and chain-end scission. Experimental data show the concentration effect of poly((x-methyl styrene)) (PAMS) on the degradation of polystyrene dissolved in mineral oil at 275 {degrees}C in a batch reactor. Samples analyzed by gel permeation chromatography yielded the time evolution of the MD. The results indicated that, owing to the interaction of mixed radicals with polymer by hydrogen abstraction, polystyrene degradation rate decreases with increasing PAMS concentration.

DOE O 232.1A, Occurrence Reporting and Processing of Operations Information, and 10 CFR 830.350, Occurrence Reporting and Processing of Operations Information (when it becomes effective), along with this manual, set forth occurrence reporting requirements for Department of Energy (DOE) Departmental Elements and contractors responsible for the management and operation of DOE-owned and -leased facilities. These requirements include categorization of occurrences related to safety, security, environment, health, or operations (``Reportable Occurrences``); DOE notification of these occurrences; and the development and submission of documented follow-up reports. This Manual provides detailed information for categorizing and reporting occurrences at DOE facilities. Information gathered by the Occurrence Reporting and processing System is used for analysis of the Department`s performance in environmental protection, safeguards and security, and safety and health of its workers and the public. This information is also used to develop lessons learned and document events that significantly impact DOE operations.

The Interaction Region Vacuum System in the PEP-II B-Factory at SLAC must produce average pressures in the 10{sup -10} Torr range. low beamline pressures will minimize the background radiation encountered by the BaBar Detector A combination of copper and stainless steel vacuum chambers with continuous antechambers are used to make up the beam tubes. Linear Non-Evaporable Getter (NEG) pumps are used to produce distributed pumping along the length of these beam tubes. High conductance microwave type screens provide RF shields between the beam aperture and the NEG pumps. In this paper the design features of the beam tubes, NEG pumps, and RF pump screens are described and the vacuum and impedance analyses conducted in support of the design are discussed.

There are several regions in the PEP-II B Factory at SLAC that require distributed pumping to deal with large photo-desorbed gas loads or to produce very low pressures (< 10{sup -9} Torr). These regions include the Low Energy Ring Wiggler dump chambers, the transitions between the High Energy Ring arcs and straight sections, and most importantly the Interaction Region. They have designed a compact Non-Evaporable Getter pump using commercial getters that combines high pumping speed and high sorption capacity. They describe the design features of the NEG pumps, and the test results from prototype pumps. In addition, they discuss future variations of this style of NEG pump.