Free-electron lasers as scientific instruments are reviewed. The present status and future prospects are delineated with attention drawn to the size, complexity, availability, and performance capability of this new tool. The Free-Electron Laser (FEL) was proposed by John Madey in 1970 (1), although earlier work, relevant to the concept, had been performed by Motz (2) and by Phillips (3). Experimental demonstration was achieved by Madey, et. al. in 1975 and 1976 (4). Since that time, FELs of diverse configurations have been operated at several laboratories around the world. At present, FEL development is focused in two directions: in constructing reliable FELs for scientific research and in extending FEL capability to vacuum ultra-violet (VUV) and even shorter wavelengths. In this article we shall only very briefly review the principles of an FEL, putting emphasis on those aspects that limit performance, after which we shall discuss the applications, present status and future prospects of FELs. Much material that we wish to present is in the form of Tables, and they are an essential part of this article.

We have calibrated and studied the performance of the MARK II drift chamber vertex detector with cosmic ray tracks collected with the chamber inside the MARK II detector at the SLC. The chamber achieves 30 {mu}m impact parameter resolution and 500 {mu}m track-pair resolution using CO{sub 2}/C{sub 2}H{sub 6}H{sub 6}(92/8) at 2 atmospheres pressure. The chamber has successfully recorded Z{sup 0} decays at the SLC, and resolved tracks in dense hadronic jets with good efficiency and high accuracy. 5 refs., 13 figs.

An analysis of the proton rapidity distribution in central {sup 16}O+Au collisions at 60 GeV/n measured in the NA35 streamer chamber detector at the CERN SPS is presented. The charge excess of positive particles over negative particles was measured. The rapidity distribution of the charge excess which can be associated with the primordial protons in the collision is studied in terms of the nuclear stopping power and is compared to the predictions of various models. 7 refs., 2 figs.

Gamma-ray damage to tank walls is typically more severe in D{sub 2}O than in H{sub 2}O moderated lattices because of the much higher ratios of slow-to-fast neutron flux. To estimate this effect it was first necessary to develop energy dependent gamma-ray displacement cross sections for iron. These, along with coupled neutron-gamma-ray transport computations, provided a measure of displacement damage from this source in SRS reactor tank walls. Gamma-ray displacements originating from high energy gammas from neutron capture in and near the tank wall exceeded those from gamma rays created in the reactor core. The displacements from the combined gamma sources ranged from 13% to 16% of that due to iron atom recoil following neutron capture. 8 refs., 2 figs., 2 tabs.

Failures in the basic materials used in nuclear power plants continue to be costly and insidious, despite increasing industry vigilance to catch failures before they degrade safety. For instance, the overall costs to the US industry from materials problems could amount to as much as $10 billion annually. Moreover, estimates indicate that the cost of a pipe failure in a nuclear plant is one hundred times greater than the cost of a similar failure in a coal-fired plant. There are important practical stimuli and much scope for further understanding of the effects of irradiation on Zr-alloys (and other materials used in nuclear installations) by careful experimentation. Moreover, these studies need to address the effect of irradiation on all components of heterogeneous systems: the metal, the oxide and the environment, and especially those processes recurring at the interphases between these components. The present paper is aimed at providing specialists with some systematic information on the subject and with important considerations on the key items for further experimentation.

This chapter evaluates the sorption behavior of metallic ions on specimen calcite as a basis for determining the importance of calcite relative to other subsurface sorbents, such as layer silicates and oxides, in controlling metal ion concentration in calcareous groundwaters. A review of the literature shows the sorption of both metallic cations and anions on calcite over ranges in pH and CO{sub 2} partial pressure to be consistent with a surface-exchange process where cations exchange with surface Ca and anions exchange with surface CO{sub 3}. A general surface-exchange model was developed to account for the effects of Ca and CO{sub 3} concentrations, pH, and calcite surface area on cation and anion sorption onto calcite. The model was applied to recently developed experimental sorption data of Zn and SeO{sub 3} on specimen calcite in equilibrium CaCO{sub 3}(aq) suspensions. The surface-exchange model was able to describe the effects of pH on both cation and anion sorption, and provided good predictions of the effects of variable CO{sub 2}(g) pressure on Zn sorption and of PO{sub 4} on SeO{sub 3} sorption. The surface-exchange model, combined with sorption constants for other phases, was used to calculate Cd sorption to a hypothetical aquifer material containing a …

For the Compton Polarimeter experiment at the Stanford Linear Accelerator the crossing point of a laser beam and an electron beam must be kept accurate and stable. An electronic system is described for the automatic tracking and correcting of the beam crossing. A remote CCD camera, relatively insensitive to electromagnetic disturbance, records small displacements of the pulsed laser beam. Video signals are analyzed at a remote station, the amount of drift from a selected reference point determined and the appropriate correction commands sent to the motorized mirror deflecting the laser beam. A description of the system, its performance and the test results are presented. 2 refs., 4 figs.

Superdeformation was first observed in the mass-190 region in {sup 191}Hg. Since then, SD bands have been found in {sup 190-194}Hg nuclei. Here we report the discovery of two such bands in {sup 194}Tl which are the first SD bands fond in this mass region that are not in Hg nuclei. Subsequently, bands have been found in two Pb nuclei. 5 refs., 1 fig.

The inclusive jet cross section and the dijet mass spectrum have been measured at the Fermilab Tevatron Collider at {radical}s = 1.8 TeV. These measurements span approximately 7 orders of magnitude in cross section and contain jets up to 400 GeV in transverse energy and dijet masses up to 950 GeV. Comparisons have been made to QCD at both orders {alpha}{sub s}{sup 2} and {alpha}{sub s}{sup 3}. 8 refs., 9 figs.

The whole-pin furnace system is a new in-cell experimental facility constructed to investigate how irradiated fuel pins may fail under potential reactor accident conditions. Extensive checkouts have demonstrated excellent performance in remote operation, temperature control, pin breach detection, and fission gas handling. The system is currently being used in testing of EBIR-II-irradiated Integral Fast Reactor (IFR) metal fuel pins; future testing will include EBR-II-irradiated mixed-oxide fuel pins. 7 refs., 4 figs.

Electron Cyclotron Current Drive (ECCD) experiments on the DIII-D tokamak have been performed using 60 GHz waves launched from the high field side of the torus. Preliminary analysis indicates rf driven currents between 50 and 100 kA in discharges with total plasma currents between 200 and 500 kA. These are the first ECCD experiments with strong first pass absorption, localized deposition of the rf power, and {tau}{sub E} much longer than the slowing-down time of the rf generated current carriers. The experimentally measured profiles for T{sub e}, {eta}{sub e} and Z{sub eff} are used as input for a 1D transport code and a multiply-ray, 3D ray tracing code. Comparisons with theory and assessment of the influence of the residual electric field, using a Fokker-Planck code, are in progress. The ECH power levels were between 1 and 1.5 MW with pulse lengths of about 500 msec. ECCD experiments worldwide are motivated by issues relating to the physics and technical advantages of the use of high frequency rf waves to drive localized currents. ECCD is accomplished by preferentially heating electrons moving in one toroidal direction, reducing their collisionality and thereby producing a non-inductively driven toroidal current. 6 refs., 4 figs.

Searches for the top quark in p{bar p} collisions at {radical}s = 1.8 TeV are described. The analyses are based on data with an integrated luminosity of 4.4 pb{sup {minus}1} recorded with the Collider Detector at Fermilab in the 1988--1989 run. An upper limit on the t{bar t} cross section is obtained. The top quark with mass below 89 GeV/c{sup 2} is excluded at the 95% CL. Prospects for searches for the top quark in the future are presented. We also briefly present results on searches for supersymmetric particles. 14 refs., 10 figs.

We expand upon our previous Monte-Carlo-type study of 3-family mass matrices which lead to the experimentally-determined KM matrix and satisfy the constraints imposed by B{sub d}--{bar B}{sub d} mixing, {vert bar}V{sub ub}/V{sub cb}{vert bar}, B{sub K} and CP violation. Scatter distributions in {vert bar}V{sub ub}V{sub cb}{vert bar}, {epsilon}{prime}/{epsilon} and x{sub s} vs m{sub t} are presented for the standard minimal Higgs structure as well as top quark mass histograms for the minimal and 2-doublet Higgs models. A top quark mass in the range of 100--200 GeV is strongly favored with all the constraints imposed, but if the lower bound on the CP-violating J-value is completely relaxed, a secondary probability peaking occurs in the mass histograms which lies above 220 GeV in the minimal Higgs model. 19 refs., 5 figs.

The design of an easily stackable, variable period length, fast excitation driven wiggler, making use of geometrically alternating substacks of Vanadium Permandur ferromagnetic laminations, interspaced with conductive, non magnetic, material laminations which act as eddy current induced field reflectors,'' is discussed and experimental results obtained with short wiggler models are presented. 7 refs., 13 figs.

Neural Networks are introduced through analogies to data analysis and electronic techniques used in high energy physics. 18 refs., 11 figs.

The US-Japan Workshop on Field-Reversed Configurations with Steady-State High-Temperature Fusion Plasma and the 11th US-Japan Workshop on Compact Toroids were held at Los Alamos National Laboratory, Los Alamos, New Mexico on November 7--9, 1989. These proceedings contain the papers presented at the workshops as submitted by the authors. These papers have been indexed separately.

A workstation-based event display program for the Fermilab Tagged Photon Spectrometer (TPS) is described. Fast displays are required to monitor detector elements, observe hit patterns and energy deposition, and to check track reconstruction. Design considerations, novel features, and performance are designed. 5 refs., 4 figs., 1 tab.

The SLD detector is nearing completion and will start physics-quality data-taking at the SLC in 1991 with a longitudinally polarized electron beam and unpolarized positron beam. The current status of the detector is reviewed and the rich program of physics measurements possible with polarization and the SLD detector is briefly presented. In particular, the left-right polarization asymmetry, A{sub LR}, will be a unique measurement for the next few years and will allow tight bounds to be set upon the mass of the top quark. 14 refs., 1 fig.

In linear accelerators with two or more bunches the beam loading of one bunch will influence the energy and energy spread the following bunches. This can be corrected by quickly changing the phase of a travelling wave structure, so that each bunch recieves a slightly different net phase. At the SLAC Linear Collider (SLC) three bunches, two (e{sup +},e{sup {minus}}) for the high energy collisions and one (e{sup {minus}}-scavenger) for producing positrons should sit at different phases, due to their different tasks. The two e{sup {minus}}-bunches are extracted from the damping ring at the same cycle time about 60 ns apart. Fast phase switching of the RF to the bunch length compressor in the Ring-To-Linac (RTL) section can produce the necessary advance of the scavenger bunch (about 6{degree} in phase). This allows a low energy spread of this third bunch at the e{sup +}-production region at 2/3 of the linac length, while the other bunches are not influenced. The principles and possible other applications of this fast phase switching as using it for multi-bunches, as well as the experimental layout for the actual RTL compressor are presented.

This paper summarizes the major model evaluation studies conducted for the MATHEW/ADPIC atmospheric transport and diffusion models used by the US Department of Energy's Atmospheric Release Advisory Capability. These studies have taken place over the last 15 years and involve field tracer releases influenced by a variety of meteorological and topographical conditions. Neutrally buoyant tracers released both as surface and elevated point sources, as well as material dispersed by explosive, thermally bouyant release mechanisms have been studied. Results from these studies show that the MATHEW/ADPIC models estimate the tracer air concentrations to within a factor of two of the measured values 20% to 50% of the time, and within a factor of five of the measurements 35% to 85% of the time depending on the complexity of the meteorology and terrain, and the release height of the tracer. Comparisons of model estimates to peak downwind deposition and air concentration measurements from explosive releases are shown to be generally within a factor of two to three. 24 refs., 14 figs., 3 tabs.

Los Alamos investigators have developed several models which are relevant to modeling Mexico City air quality. The collection of models includes: meteorological models, dispersion models, air chemistry models, and visibility models. The models have been applied in several different contexts. They have been developed primarily to address the complexities posed by complex terrain. HOTMAC is the meteorological model which requires terrain and limited meteorological information. HOTMAC incorporates a relatively complete description of atmospheric physics to give good descriptions of the wind, temperature, and turbulence fields. RAPTAD is a dispersion code which uses random particle transport and kernel representations to efficiently provide accurate pollutant concentration fields. RAPTAD provides a much better description of tracer dispersion than do Gaussian puff models which fail to properly represent the effects of the wind profile near the surface. ATMOS and LAVM treat photochemistry and visibility respectively. ATMOS has been used to describe wintertime chemistry of the Denver brown cloud. Its description provided reasonable agreement with measurements for the high altitude of Denver. LAVM can provide both numerical indices or pictoral representations of visibility effects of pollutants. 15 refs., 74 figs.

A new data acquisition technique (the Continuously-varied Bias- voltage Acquisition mode) has been developed and tested for the low-flux broad-energy regime characteristic of existing fusion blanket mock-ups. This method of analysis allows for the acquisition of data spanning several orders of magnitude in energy with a single proportional counter. Utilizing this method, the gamma energy deposition in a mixed neutron and gamma field was measured. 7 refs., 5 figs.

Many organizations, in several countries, are planning or implementing new or upgraded research reactor projects, but there has been no organized forum devoted entirely to discussion and exchange of information in this field. Over the past year or so, informal discussions resulted in widespread agreement that such a forum would serve a useful purpose. Accordingly, a proposal to form a group was submitted to the leading organizations known to be involved in projects to build or upgrade reactor facilities. Essentially all agreed to join in the formation of the International Group on Research Reactors (IGORR) and nominated a senior staff member to serve on its international organizing committee. The first IGORR meeting took place on February 28--March 2, 1990. It was very successful and well attended; some 52 scientists and engineers from 25 organizations in 10 countries participated in 2-1/2 days of open and informative presentations and discussions. Two workshop sessions offered opportunities for more detailed interaction among participants and resulted in identification of common R D needs, sources of data, and planned new facilities. Individual papers have been cataloged separately.

We have measured the ratio of the isomer to ground-state yields of {sup 137}Ce produced in the fusion reactions {sup 128}Te({sup 12}C,3n), {sup 133}Cs({sup 7}Li,3n), {sup 136}Ba({sup 3}He,2n), {sup 136}Ba({sup 4}He,3n), and {sup 137}Ba({sup 3}He,3n), from energies above the Coulomb barrier to energies typically 20--30% below the barrier by observing the delayed x- and {gamma}-ray emission. We deduce the average angular momentum, {lt}J{gt}, from the measured isomer ratios with a statistical model. In the first three reactions we observe that the values of {lt}J{gt} exhibit the behavior predicted for low energies and the expected variation with the reduced mass of the entrance channel. We analyze these data and the associated cross sections with a barrier penetration model that includes the coupling of inelastic channels. Measurements of average angular momenta and cross sections made on other systems using the {gamma}-multiplicity and fission-fragment angular correlation techniques are then analyzed in a similar way with this model. The discrepancies with theory for the {gamma}-multiplicity data show correlations in cross section and angular momentum that suggest a valid model can be found. The measurements of angular momentum using the fission fragment angular correlation technique, however, do not appear reconcilable with the energy dependence of …