Construction of a sixteen beam (0.5 A per beam) injector for use in scaled heavy ion fusion experiments is underway at LBL. The machine was designed and partially constructed at LANL. The injector is designed to use carbon arc sources which will provide 25 mA/cm/sup 2/ of extractable current density. The plasma from the arcs is confined electrostatically from drifting into the ion gun before firing the extraction pulse. The acceleration column consists of a set of aperture lenses which both transport the beam and attenuate backstreaming electrons. The acceleration column is mounted inside a 28-inch diameter brazed alumina insulating module. The high voltage for the injector is provided by an inductively loaded and graded Marx generator which resides inside a pressure vessel filled with a 65 psig mixture of 30/percent/ SF/sub 6/ and 70/percent/ N/sub 2/. Data is presented showing the performance of single and multiple carbon arc sources. Measurements show that adequate current density is available. Emittance measurements and efforts to improve emittance and reproducibility are shown. Tests with a 5-tray section of the full 18 tray generator are described showing the evolution of the generator design. 5 refs., 3 figs.

The multiple beam accelerator MBE-4 is a device for research toward a heavy ion driver for inertial confinement fusion, based on the induction linac concept. Its main goal is proof of the principle of current amplification by acceleration and controlled self-similar beam pulse compression. Into the 16-m long device four beams, each with an initial current of 10 mA are injected from a Marx-driven diode at 200 keV. The current amplification is up to nine-fold, with a final beam energy of about 800 keV in the middle of the bunch. Now that all the apparatus' accelerator sections have been completed, installed and aligned, and its unaccelerated transport properties have been studied, our experimental research has reached the crucial phase of implementing appropriate accelerator schedules that approximate self-similar current-pulse compression. These schedules are established through a close interplay of computations using a one-dimensional simulation code and a manual empirical tuning procedure. In a first approach, with a rather vigorous schedule that uses most of the accelerator modules to their voltage limits, we have determined the limits of our capability for controlled pulse compression, mainly due to waveform shaping of the driving pulse-forming networks. We shall report on these results. In the …

The lattice configuration of the beam combiner and bend system of the proposed Induction Linac System Experiment (ILSE) is described. These subsystems must transport high current ion beams with large momentum variations within a single pulse (..delta..P/P/sub 0/ less than or equal to +-.1), with minimal beam loss or emittance growth. Configurations which are achromatic through first order, including the effect of image fields have been developed. Calculations of the beam envelope and centroid motion are made with beam dynamics code HICURB, which includes strong space charge effects and chromatic effects through all orders. 5 refs., 5 figs.

At the present time a Monte Carlo transport computer code is being designed and implemented at Lawrence Livermore National Laboratory to include the transport of: neutrons, photons, electrons and light charged particles as well as the coupling between all species of particles, e.g., photon induced electron emission. Since this code is being designed to handle all particles this approach is called the ''All Particle Method''. The code is designed as a test bed code to include as many different methods as possible (e.g., electron single or multiple scattering) and will be data driven to minimize the number of methods and models ''hard wired'' into the code. This approach will allow changes in the Livermore nuclear and atomic data bases, used to described the interaction and production of particles, to be used to directly control the execution of the program. In addition this approach will allow the code to be used at various levels of complexity to balance computer running time against the accuracy requirements of specific applications. This paper describes the current design philosophy and status of the code. Since the treatment of neutrons and photons used by the All Particle Method code is more or less conventional, emphasis in …

The authors have two amplitude and phase measuring acoustic microscopes, one at low frequency (3--10 MHz) which is used for measurements in metals and composites, and the other operating at frequencies of up to 200 MHz which is used for higher resolution measurements. The added dimension of having phase information allows one to use image processing for a variety of applications. They have demonstrated the following applications with these two microscopes: inversion for reflectance function calculations, depth determination for delaminations in composite materials, slowness curve measurements of depth of trenches in aluminum samples (scaled problem of silicon trenches), and measurement of visco-elastic properties of thin surfactant films on a water surface.

Longitudinal coupled bunch instability has been observed in the Fermilab Booster at high intensity. It is a cause for concern due to its effect on the Tevatron collider performance. We study this phenomenon using initial value technique to correctly account for the underlying transient nature. Analytic result is obtained for any mode and comparison is made between ordinary harmonic potential and higher harmonic (Landau) cavity potential. A computer program is developed to facilitate the calculation. The result shows that the merit of Landau cavity is best realized in cases where the resonance is of a broad band nature. 5 refs., 4 figs., 3 tabs.

The US Nuclear Regulatory Commission has established two post-closure performance objectives for the Engineered Barrier System (EBS) in a geologic repository. These require containment of the waste followed by controlled release. The EBS for a repository in unsaturated tuff at Yucca Mountain is designed to meet these performance objectives. The major components are the waste form, container, air gap, and borehole liner. Assessment of post-closure performance of the EBS is based on allocating performance for various components toward meeting overall design objectives. Because of the unprecedented time periods considered, 1000 to 10,000 years, computer modeling is essential and will be used in conjunction with testing to assess whether the performance allocations are met. 7 refs., 1 tab.

The current situation concerning supernova simulations and the theory of neutron star structure are studied with respect to what they tell about the equation of state. A new mechanism that could help power supernovae is suggested.

This paper considers the problem of determining a confidence interval for the difference between two treatments in a simplified sequential paired clinical trial, which is analogous to setting an interval for the drift of a random walk subject to a parabolic stopping boundary. Three bootstrap methods of construction are applied: Efron's accelerated bias-covered, the DiCiccio-Romano, and the bootstrap-t. The results are compared with a theoretical approximate interval due to Siegmund. Difficulties inherent in the use of these bootstrap methods in a complex situations are illustrated. The DiCiccio-Romano method is shown to be the easiest to apply and to work well. 13 refs.

We describe a method and a way of thinking which is ideally suited for the study of systems represented by canonical integrators. Starting with the continuous description provided by the Hamiltonians, we replace it by a succession of preferably canonical maps. The power series representation of these maps can be extracted with a computer implementation of the tools of Non-Standard Analysis and analyzed by the same tools. For a nearly integrable system, we can define a Floquet ring in a way consistent with our needs. Using the finite time maps, the Floquet ring is defined only at the locations s/sub i/ where one perturbs or observes the phase space. At most the total number of locations is equal to the total number of steps of our integrator. We can also produce pseudo-Hamiltonians which describe the motion induced by these maps. 15 refs., 1 fig.

We discuss the quantization of chiral gauge theories by lattice regularization, carefully treating the effects of the chiral anomaly. We derive a chiral gauge invariant lattice fermion action from a chiral gauge variant Wilson fermion action without changing its partition function. By lattice power counting for this formula we show that anomalous gauge theories as well as anomaly-free gauge theories are renormalizable even in 4-dimensions. Some applications and implications of this result and problems therein are discussed. 16 refs.

The coherent betatron instability was first observed during the recent 1987-88 Tevatron fixed target run. In this operating mode 1000 consecutive bunches are loaded into the machine at 150 GeV with a bunch spacing of 18.8 /times/ 10/sup -9/ sec (53 MHz). The normalized transverse emittance is typically 15 ..pi.. /times/ 10/sup -6/ m rad in each plane with a longitudinal emittance of about 1.5 eV-sec. The beam is accelerated to 800 GeV in 13 sec. and then it is resonantly extracted during a 23 sec flat top. As the run progressed the bunch intensities were increased until at about 1.4 /times/ 10/sup 10/ppb (protons per bunch) we experienced the onset of a coherent horizontal oscillation taking place in the later stages of the acceleration cycle (>600 GeV). This rapidly developing coherent instability results in a significant emittance growth, which limits machine performance and in a catastrophic scenario it even prevents extraction of the beam. In this paper we will present a simple analytic description of the observed instability. We will show that a combination of a resistive wall coupled bunch effect and a single bunch slow head-tail instability is consistent with the above observations. Finally, a systematic numerical analysis …

One of the threats of concern to facilities using significant quantities of radioactive material is radiological sabotage. Both the Department of Energy (DOE) and the US Nuclear Regulatory Commission have issued guidance to facilities for radiological sabotage protection. At those facilities where the inventories of radioactive materials change frequently, there is an operational need for a technically defensible method of determining whether or not the inventory of radioactive material at a given facility poses a potential radiological sabotage risk. In order to determine quickly whether a building is a potential radiological sabotage target, Lawrence Livermore National Laboratory (LLNL) has developed a radiological sabotage consequence index that provides a conservative estimate of the maximum potential off-site consequences of a radiological sabotage attempt involving the facility. This radiological sabotage consequence index can be used by safeguards and security staff to rapidly determine whether a change in building operations poses a potential radiological sabotage risk. In those cases where such a potential risk is identified, a more detailed radiological sabotage vulnerability analysis can be performed. 1 tab.

There were four large-scale sodium fire tests completed to provide a data base for computer code validation; three for the ABCOVE program and one for the SOFICOV program. The purpose of the ABCOVE program is to provide a basis for judging the adequacy of existing aerosol behavior computer codes to describe inherent aerosol attenuation in containment buildings during postulated accidents. The program involves both analytical calculations by code developers and users, and large-scale confirmatory tests in the 850-m/sup 3/ containment vessel of the Containment Systems Test Facility (CSTF) operated by the Westinghouse Hanford Company. A key element of both programs is that all code calculations are made without knowledge of the experimental results, and thus, provide a true measure of the code capabilities without benefit of post-test fitting.

The physical presence of vacuum structures can be expressed in terms of a coupling impedance experienced by the beam. The beam environment considered here consist of parasitic higher order modes of the r.f. cavities. These resonances may have high enough Q's to allow consecutive bunches to interact through mutually induced fields. The cumulative effect of such fields as the particles pass through the cavity may be to induce a coherent buildup in synchrotron motion of the bunches, i.e., a longitudinal coupled-bunch instability. The colliding mode operation of the present generation of high energy synchrotrons and the accompanying r.f. manipulations, make considerations of individual bunch area of paramount importance. Thus, a longitudinal instability in one of a chain of accelerators, while not leading to any immediate reduction in the intensity of the beam in that accelerator, may cause such a reduction of beam quality that later operations are inhibited (resulting in a degradation performance). In this paper we employ a longitudinal phase-space tracking code (ESME) as an effective tool to simulate specific coupled bunch modes arising in a circular accelerator. One of the obvious advantages of the simulation compared to existing analytic formalisms, e.g., based on the Vlasov equation, is that …

To examine one aspect of the feasibility of suppressing transverse coupled-bunch motion, an estimate of the kicker power and bandwidth will be made. We expect that large power will not be required, so that the kicker electrode need not provide maximum coupling. This also reduces its contribution to the beam impedance, which is calculated at the end of this paper. 1 ref., 1 fig.

As part of a two-beam accelerator research program /similar to/33 GHz accelerator sections have been designed and fabricated by both the machined-and-brazed technique and the electroforming technique. These procedures are summarized in this paper. Special requirements included a filling time of about 14 ns, +- 1.25 ..mu..m dimensional tolerances, input VSWR less than or equal to1.10, radial vacuum pumping for each cell, and a capability for a 200--300 MV/m accelerating gradient. A 34-cavity, 2..pi../3 mode, quasi-constant gradient, v/sub p/ = c, /similar to/10 cm-long, disc-loaded waveguide structure design and chosen with optimized sidewall input/output iris couplers. 13 refs., 5 figs., 1 tab.

The Advanced Light Source, under construction at the Lawrence Berkeley Laboratory, will use a 50 MeV, 3 GHz linac as preinjector. The linac will operate in two modes---a single-bunch mode of 4 nC/pulse and a 100--150 nanosecond multibunch mode with 125 mA average current. In both modes an rms momentum spread of <0.3% is needed. The linac injection system consists of a high-intensity gun, followed by two subharmonic bunchers (one of 1/24th, and the other of 1/6th the linac frequency), an S-band buncher at the linac frequency and the first few cavities of the linac (the capture section). The beam experiences strong space-charge forces and nonlinearities which cause emittance growth. Expected performance is analyzed with computer simulations. 6 refs., 5 figs.

The modular high temperature gas-cooled reactor (MHTGR) is a 350 MW(t) second generation reactor system design which during normal operation circulates helium with a mixed mean coal and hot temperature of 260/sup 0/C (500/sup 0/C) and 690/sup 0/C (1270/sup 0/F), respectively. The design incorporates passive design features which allow the plant to be safely shutdown and cooled with no active systems or operator action being required. A key feature of this concept is the capability of the residual heat removal by passive conduction cooldown from the core to the reactor cavity via an uninsulated vessel. The MHTGR uses a number of metallic components. A description of these components and their design requirements are presented in this paper.

Deuterium plasma recycling and chemical erosion behavior of selected graphite materials have been investigated using the PISCES-A facility. These materials include: Pyro-graphite; 2D-graphite weave; 4D-graphite weave; and POCO-graphite. Deuterium plasma bombardment conditions are: fluxes around 7 /times/ 10/sup 17/ ions s/sup /minus/1/cm/sup /minus/2/; exposure time in the range from 10 to 100 s; bombarding energy of 300 eV; and graphite temperatures between 20 and 120/degree/C. To reduce deuterium plasma recycling, several approaches have been investigated. Erosion due to high-fluence helium plasma conditioning significantly increases the surface porosity of POCO-graphite and 4D-graphite weave whereas little change for 2D-graphite weave and Pyro-graphite. The increased pore openings and refreshed in-pore surface sites are found to reduce the deuterium plasma recycling and chemical erosion rates at transient stages. The steady state recycling rates for these graphite materials can be also correlated to the surface porosity. Surface topographical modification by machined-grooves noticeably reduces the steady state deuterium recycling rate and the impurity emission from the surface. These surface topography effects are attributed to co-deposition of remitted deuterium, chemically sputtered hydrocarbon and physically sputtered carbon under deuterium plasma bombardment. The co-deposited film is found to have a characteristic surface morphology with dendritic microstructures. 18 ref., 4 …

There is a continuing study in the USA of the feasibility of an induction linac fusion driver, which would accelerate multiple heavy-ion beams through a sequence of pulsed transformers and amplify the beam current during acceleration. The driver cost could be $200/Joule or less and the cost of electricity in the range of .050-.055$/kWhr. As a next stage of development to assess the feasibility of this approach we propose an ''Induction Linac Systems Experiment''. This will test some of the technology and multiple-beam manipulations necessary for a fusion driver. 7 refs., 1 fig.

Dielectron production has been measured in p+Be collisions at 1.0, 2.1 and 4.9 GeV, and in Ca+Ca at 1.0 and 2.0 GeV/A. The observation of a structure in the mass cross section at about two times the pion mass suggests that pion annihilation is the dominant production mechanism in p+Be above 2 GeV. Comparison of preliminary results from p+Be and Ca+Ca at 1 GeV/A is presented. 7 refs., 5 figs., 1 tab.

A search for pairs of high p/sub T/ prompt photons produced in hydrogen by a 280 GeV/c incident /pi//sup /minus// beam has been carried out using a fine-grained electromagnetic calorimeter and the Omega spectrometer at the CERN SPS. Clear evidence for the existence of such events is found with a six standard deviation signal for p/sub T/ > 3.0 GeV/c. The cross sections are consistent with beyond leading order QCD calculations. A discussion on the determination of /alpha//sub s/ is also presented. 18 refs., 7 figs., 7 tabs.

The electromagnetic interaction needs no introduction as a probe of the structure of systems on many scales. The continued use of this technique dominated the sessions on Electron and Muon Physics at the Samoset Meeting. The experimental results continue to stimulate large numbers of theorists and the results on polarized deep inelastic muon scattering and their various interpretations permeated beyond these sessions. The breadth of physics attacked with electrons and muons makes a summary such as this rather peculiar. As one of my nuclear physics friends (I think) commented after my summary, ''it was interesting to see Nuclear Physics from a long distance with the telescope inverted.'' The comment may well be applied to this written version of the summary talk. 21 refs.