Beams of unstable nuclei can be formed by direct injection of the radioactive atoms into an ion source, or by using the momentum of the primary production beam as the basis for the secondary beam. The effectiveness of this latter mechanism in secondary beam formation, i.e., the quality of the emerging beam (emittance, intensity, energy spread), depends critically on the nuclear reaction kinematics, and on the magnitude of the incident beam energy. When this beam energy significantly exceeds the energies typical of the nuclear reaction process, many of the qualities of the incident beam can be passed on to the secondary beam. Factors affecting secondary beam quality are discussed, along with techniques for isolating and purifying a specific secondary product. The ongoing radioactive beam program at the Bevalac is used as an example, with applications, present performance and plans for improvements.

Thermal damage to susceptible material in accessible regions of the reactor building was distributed in non-uniform patterns. No clear explanation for non-uniformity was found in examined evidence, e.g., burned materials were adjacent to materials that appear similar but were not burned. Because these items were in proximity to vertical openings that extend the height of the reactor building, we assume the unburned materials preferentially absorbed water vapor during periods of high, local steam concentration. Simple hydrogen-fire-exposure tests and heat transfer calculations duplicate the degree of damage found on inspected materials from the containment building. These data support estimated 8% pre-fire hydrogen concentration predictions based on various hydrogen production mechanisms.

The Transverse Field Focusing (TFF) system described here is a prototype for a negative-ion based neutral beam line with possible applications in the US magnetic fusion energy program. The prototype system consists of four main modules: (1) H/sup -/ source, (2) 80 keV pre-accelerator, (3) TFF matching/pumping (M/P) section, and (4) 180 keV TFF accelerator. The first three modules have been installed on the beam line, with the fourth to follow soon. The crucial module, invoking the most difficult (and interesting) physics and engineering issues, is the M/P section. It performs: (a) gas removal from the beam by differential pumping, (b) electron removal, (c) beam thickness reduction to match the TFF accelerator parameters, and (d) beam-edge confinement. The four beamline modules are discussed in this survey, with emphasis on design features of the M/P section. 17 refs., 4 figs.

MBE-4, a heavy-ion multiple beam induction linac being built at LBL in FY85/86, will model many features of a much longer device. It will accelerate four space-charge-dominated cesium ion beams from, for example, 0.2 MeV, 5 mA/beam, 3.0 ..mu..sec, 1.6 m length at injection to approx.0.8 MeV, 15 mA/beam, 1.0 ..mu..sec, 1.1 m length at the exit. It will permit study of simultaneous focussing, acceleration, current amplification and emittance growth of multiple space-charge-dominated ion beams. Some features of this accelerator are described. 11 refs., 5 figs.

A new type of anomaly is discussed that afflicts certain non-linear sigma models with fermions. This anomaly is similar to the ordinary gauge and gravitational anomalies since it reflects a topological obstruction to the reparametrization invariance of the quantum effective action. Nonlinear sigma models are constructed based on homogeneous spaces G/H. Anomalies arising when the fermions are chiral are shown to be cancelled sometimes by Chern-Simons terms. Nonlinear sigma models are considered based on general Riemannian manifolds. 9 refs. (LEW)

We have searched for the production of likesign dilepton events (nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup -/ + ...) in a wideband neutrino beam at FNAL using the 15' bubble chamber. We observe no signal above the background arising from conventional sources. We set 90% confidence level upper limits for the production rates of (nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup -/ + ...)/(nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + ...) less than or equal to 8 * 10/sup -5/ and (nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup -/ + ...)/(nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup +/ + ...) less than or equal to 6 * 10/sup -2/.

A history of the Particle Data Group's efforts to find a rational and systematic convention for naming mesons and baryons is given. Several versions of our proposal are reviewed, and name changes which would occur are summarized. Some of the mail we have received is described. We hope to stimulate additional feedback.

Pump neutral beams, which are directed into the loss cone of the TMX-U plugs, are normally used to pump ions from the thermal barriers. Because these neutral beams introduce cold gas that reduces pumping efficiency, and require a straight line entrance and exit from the plug, alternate methods are being investigated to provide barrier pumping. To maintain the thermal barrier, either of two classes of particles can be pumped. First, the collisionally trapped ions can be pumped directly. In this case, the most promising selection criterion is the azimuthal drift frequency. Second, the excess sloshing-ion density can be removed, allowing the use of increased sloshing-beam density to pump the trapped ions. The selection mechanism in this case is the Doppler-shifted ion-cyclotron resonance of the high-energy sloshing-ions (3 keV less than or equal to U/sub parallel/ less than or equal to 10 keV).

Angular distributions of fission fragments produced in the /sup 232/Th(n,f) reaction have been measured in 40-keV intervals. A simplified reaction model was adopted, and a channel analysis done for 0.72 less than or equal to E/sub n/ (MeV) less than or equal to 4.5. An anomaly at E/sub n/ = 2.98 MeV suggests that K remains a good quantum number some 2 MeV above fission threshold. The percentage contribution to the cross section of K = 3/2 states for incident neutron energies between 1.1 and 1.3 MeV is larger than previously thought. 7 refs.

Optimizing the performance of a single-pass free electron laser (FEL) in a storage ring requires a stored beam having both a relatively high volume density and a low momentum spread. These requirements place severe constraints on storage ring design due to the impact of both coherent and incoherent multiparticle phenomena. In this paper we present approximate scaling laws that elucidate the relative importance of various lattice parameters, and we will describe a systematic approach (embodied in the computer code ZAP) to parameter selection. 9 refs., 1 fig.

The process of longitudinal compression of a drifting heavy ion pulse to be used as an ICF driver is examined with the aid of particle simulation. Space charge forces play a vital role in halting compression before the final focus lens system is reached. This must take place with minimal growth of transverse emittance and momentum spread. Of particular concern is the distortion of longitudinal phase space by the rounded transverse profile of the longitudinal self-electric field.

The possibility of experimental observation of the triply charmed ccc baryon ..cap omega../sub ccc//sup + +/ is explored. The conclusion is that it is very difficult, but not unthinkable. 11 refs.

Recent measurements of R, the ratio of the total hadron cross section to the lowest order muon pair cross section, are discussed which have systematic overall scale errors on the absolute value of R of 7% or less. Experiments are reviewed that have sought exotic effects in e/sup +/e/sup -/ at the highest available energies. The search for narrow states in the radiative decays of the J/psi and UPSILON are also reviewed. 35 refs., 24 figs. (LEW)

Accelerator injector designs have been evaluated using two computer codes. The first code self consistently follows relativistic particles in two dimensions. Fields are obtained in the Darwin model which includes inductive effects. This code is used to study cathode emission and acceleration to full injector voltage. The second code transports a fixed segment of a beam along the remainder of the beam line. Using these two codes the effects of electrode configuration on emittance, beam quality and beam transport have been studied.

A recent concept for collective acceleration and focusing of a high energy electron bunch is discussed, in the context of its possible applicability to large linear colliders in the TeV range. The scheme can be considered to be a member of the general class of two-beam accelerators, where a high current, low voltage beam produces the acceleration fields for a trailing high energy bunch.

An ion source is described in which a metal vapor vacuum arc is used to create the plasma from which the ions are extracted. Beams of a variety of ions have been produced, ranging from lithium up to uranium. At an extraction voltage of 25 kV we've measured an ion beam current of over 1 Ampere, with over 550 ema of the beam in an emittance of 0.07..pi.. cm. mradians (normalized). The ion charge state distribution varies with cathode material and with arc power; for uranium a typical distribution is peaked at U/sup 5 +/, with up to 40% of the beam current in this charge state. 27 refs., 10 figs.

A property of the second-order achromat, whereby dipole and sextupole families may be inserted into a lattice for chromatic corrections without introducing second-order geometrical (on momentum) optical distortions, has been incorporated in several new particle accelerator designs. These include the SLC at SLAC, LEP at CERN, the EROS pulse stretcher ring at Saskatoon, the CEBAF ring at SURA, and the MIT ring.

Small bore conventional dc quadrupoles with apertures from 1 to 2.578cm were designed and prototypes built and measured. New fabrication techniques including the use of wire electric discharge milling (EDM) to economically generate the pole tip contours and aperture tolerances are described. Magnetic measurement data from a prototype of a 1cm aperture quadrupole with possible use in future e/sup +//e/sup -/ super colliders are presented. At a current of 400A, the lens achieved a gradient of 2.475 T/cm, and had an efficiency of 76.6%.

Several techniques using small radius collimating pipes with and without axial magnetic fields to measure the brightness of an extracted 1 - 2 kA, 1 - 1.5 MeV electron beam will be described. The output beam of the High Brightness Test Stand as measured by one of these techniques is in excess of 2 x 10/sup 5/ amp/cm/sup 2//steradian. 5 refs., 4 figs.

The standard paraxial ray equation method for the design of electrodes for an electrostatically focused gun is extended to include relativistic effects and the effects of the beam's azimuthal magnetic field. Solutions for parallel and converging beams are obtained and the predicted currents are compared against those measured on the High Brightness Test Stand. 4 refs., 2 figs.

Two dimensional cartesian and axially-symmetric problems in electrostatics or magnetostatics frequently are solved numerically by means of relaxation techniques - employing, for example, the program POISSON. In many such problems the ''sources'' (charges or currents, and regions of permeable material) lie exclusively within a finite closed boundary curve and the relaxation process in principle then could be confined to the region interior to such a boundary - provided a suitable boundary condition is imposed onto the solution at the boundary. This paper discusses and illustrates the use of a boundary condition of such a nature in order thereby to avoid the inaccuracies and more extensive meshes present when alternatively a simple Dirichlet or Neumann boundary condition is specified on a somewhat more remote outer boundary.

The Fermilab Antiproton Source Accumulator and Debuncher rings require 5 kickers in total. These range in design from conventional ferrite delay line type magnets, with ceramic beam tubes to mechanically complex shuttered kickers situated entirely in the Accumulator Ring's 10/sup -10/ torr vacuum. Power supplies are thyratron switched pulse forming networks that produce microsecond width pulses of several kiloamps with less than 30 nanoseconds rise and fall times. Kicker and power supply design requirements for field strength, vacuum, rise and fall time, timing and magnetic shielding of the stacked beam in the accumulator by the eddy current shutter will be discussed. 8 refs., 3 figs., 2 tabs.

A particle simulation code was used to study the effect on transverse beam dynamics of nonlinearities of the focusing field in a linear accelerator transporting a multiple beam array. Nonlinear field strengths for various multiple-beam design geometries were calculated by relaxation codes for use in the simulation calculation. Nonlinearities due to asymmetry of the electrode array with respect to a single beam were found to be negligible. Electrode end effect nonlinearities led to emittance growth for off-axis beams, though for the geometry of MBE-4, this was negligible. For misaligned beams, a dodecapole field caused significant emittance growth. This was not seen in single particle tracking calculations. Fields due to induced charge on the electrodes can reduce this effect, or the dodecapole field can be eliminated by proper choice of the electrode radius.

A particle simulation code has been used to study the effect of transverse beam dynamics of charge induced on focusing electrodes. A linear transport system was assumed. The initial particle distribution was taken to be that of a uniform elliptical beam with a Gaussian velocity distribution. For misaligned, highly space-charge-dominated beams (betatron phase advance per lattice period less than or equal to 10/sup 0/), a large oscillation of the rms emittance occurred in a beat pattern. Linearized Vlasov analysis shows the oscillation to be a sextupole oscillation, driven by the beam coherent betatron motion. Emittance growth accompanied the oscillation. Preliminary experimental results from the Single Beam Transport Experiment (SBTE) are consistent with the code results. Addition of a dodecapole nonlinearity to the computational focusing field greatly reduces the oscillation amplitude.