Introduction

Over the past 30 years synchrotron radiation (SR) sources have evolved to become the premier generators of radiation for scientific experimentation in the basic and applied sciences as well as for technological applications in numerous fields or industries critical to human welfare and society. From the outset, the machines and insertion devices (viz., bending magnets, wigglers, and undulators) used to produce this radiation have been systematically improved to near their theoretical limits of operation. Notwithstanding these achievements, research has actively continued on even newer machine concepts and modes of operation to further extend what are now the conventionally accepted theoretical norms. In contemporary SR research machines of the established class are referred to as "3rd Generation (3G)" sources and those of the developing class as "4G" machines. Informally, 4G machines a re defined as those that feature an order-of-magnitude or more increase or improvement in any of the phase space parameters (viz., source flux, emittance, brightness, coherence, etc.) of the radiation of earlier-generation sources. One singular feature of modern 3G sources (e.g., the European Synchrotron Radiation Facility (ESRF), the Advanced Photon Source (APS), the Super Photon ring-8 GeV (SPring-8), etc.) is their relatively high (>6 GeV) energies of operation and consequently large sizes (> 1 km circ umferences). These facilities are characterized by extraordinary cost (sizeable fractions of $1B USD) and large numbers of beam lines (on the order of hundreds), to which scientists from all over the world must come to perform their experiments.

In contrast to the huge scale of these extraordinarily productive machines, which to some extent stems from the fact that their direct predecessors were the high energy (> 1 GeV) machines used for particle physics, it has long been known that the spectral flux that can be emitted by an insertion device on a storage ring can, under suitable conditions, increase in root-inverse proportion to the machine energy and in linear inverse proportion to insertion device wavelength (i.e., the lower the machine energy and the shorter the insertion device period, the greater the radiation output). In view of this fundamental fact, one of the directions of 4G synchrotron radiation source research over the pas t few decades (at SLAC and elsewhere) has been to study and develop the insertion device and storage ring technologies that could make the realization of such smaller-scale, more powerful machines possible.

Given this background the NESTOR ("Next-generation Electron STOrage Ring") project has been advanced, starting during the latter 90's, by the scientific staff of the Kharkov Institute of Physics and Technology (KIPT) in Ukraine to develop, on the basis of the most advanced laser and storage ring technologies that have been achieved around the world, a compact storage ring x-ray source utilizing a laser beam as an (ultra-short-period) undulator. This project has been organized as a collaborative research effort among five international laboratories and institutes of higher learning and has been awarded a three year grant by NATO under its Science for Peace Program. Due to the project's potential economic and scientific significance, matchi ng support commitments have also been established by the Ukrainian government. The grant term is due to expire in February of 2006, at which time the advanced x-ray source is expected to be ready for initial commissioning studies. Since its inception, the development effort has been managed from SLAC, whose mission statement underscores an almost point-for-point consistency with the technical and scientific goals of the NESTOR project.