The reactions Ca + Ca and Nb 4-Nb at 400 MeV/nucleon have been studied at the Bevalac using the "Plastic Ball" spectrometer. A global analysis of the events shows two nontrivial collective flow effects: the bounceoff of the projectile fragments, and the side-splash of the intermediate-rapidity fragments for the higher-multiplicity Nb + Nb events. Neither effect is seen in a knockon cascade calculation. A simulation with an event-generating statistical model has been done in order to extract the magnitudes of the effects.

Clinical trials using accelerated heavy charged-particle beams for treating cancer and other diseases have been performed for nearly four decades. Recently there have been worldwide efforts to construct hospital-based medically dedicated proton or light-ion accelerator facilities. To make such accelerated heavy charged-particle beams clinically useful, specialized instruments must be developed to modify the physical characteristics of the particle beams in order to optimize their biological and clinical effects. This article reviews the beam modifying devices and associated dosimetric equipment developed specifically for controlling and monitoring the clinical beams.

The design of a high resolution photoemission electron microscope ͑PEEM͒ for the study of magnetic materials is described. PEEM is based on imaging the photoemitted ͑secondary͒ electrons from a sample irradiated by x rays. This microscope is permanently installed at the Advanced Light Source at a bending magnet that delivers linearly polarized, and left and right circularly polarized radiation in the soft x-ray range. The microscope can utilize several contrast mechanisms to study the surface and subsurface properties of materials. A wide range of contrast mechanisms can be utilized with this instrument to form topographical, elemental, chemical, magnetic circular and linear dichroism, and polarization contrast high resolution images. The electron optical properties of the microscope are described, and some first results are presented.

We report the results of our research and development in techniques for producing elliptical x-ray mirrors by controlled bending of a flat substrate. We review the theory and technique of mirror bending with emphasis on the optical engineering issues and describe our design concepts for both metal and ceramic mirrors. We provide analysis of the various classes of error that must be addressed to obtain a high quality elliptical surface and a correspondingly fine focus of the x-ray beam. We describe particular mirrors that have been built, using these techniques, to meet the requirements of the scientific program at the Advanced Light Source at Lawrence Berkeley National Laboratory. For these examples, we show optical metrology results indicating the achievement of surface accuracy values around and, in some cases, below 1 rad as well as x-ray measurements showing submicrometer focal spots.

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A system for spreading relativistic heavy ion beams into large uniform radiation fields has been developed. The charged particles passing through the system are deflected into azimuthally symmetric distributions which can then be superimposed to produce dose distributions as large as 30 cm in diameter with less than +/- 3.5% variation in uniformity.

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