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The introduction of trajectory oscillations to reduce emittance growth in the SLC linac
Emittance growth of accelerated beams in the 50 GeV linear accelerator of the Stanford Linear Collider (SLC) arises from the effects of transverse wakefields and momentum dispersion. These effects are caused by small misalignments of the beam position monitors, lattice quadrupoles, and accelerating structure and by the energy spectrum of the beam which changes along the accelerator. The introduction of strategically placed trajectory oscillations over finite lengths of the linac has been used to generate beam errors which cancel the emittance accumulation from these small unknown, random alignment errors. Induced oscillations early in the linac cancel effects which filament along the accelerator affecting mostly the beam core. Induced oscillations located at the center of the accelerator or beyond cancel wakefield and dispersion errors which do not completely filament but cause the beams to have, in addition, an apparent betatron mismatch and transverse tails. The required induced oscillations of a few hundred microns are reasonably stable over a period of several weeks. Of course, the optimum induced oscillations depend upon the beam charge. Emittance reductions of 30 to 50% have been obtained
Entrepreneurship in East Asian Regional Innovation Systems: Role of social capital
This paper analyzes the role of social capital in entrepreneurial RIS (Regional Innovation Systems). We disaggregate the features of mature entrepreneurial RIS into three dimensions of social capital: structural, relational, and cognitive. We apply these features of mature entrepreneurial RIS to the still-evolving entrepreneurial RIS from East Asia including Daedeok Innopolis of Korea and Hsinchu Science Park of Taiwan. The spawning effect of representative companies within focal industries, collaboration among the key organizational actors, and attraction and retention of talent are taken into account. The study uncovers a new aspect of still-evolving entrepreneurial RIS, which complements the existing typology categorizing RIS into institutional RIS and entrepreneurial RIS. Whereas the conventional literature has viewed the East Asian RIS as institutional RIS, the findings of this study allow scholars to view the East Asian RIS as entrepreneurial in their own distinctive manner. Meanwhile, we also find an important implication for making a shift from a top-down to a bottom-up approach in order for the still-evolving entrepreneurial RIS to vitalize cognitive social capital. Thus, we suggest the transitions from outward-looking social capital to inward-looking social capital