Optimization and design of cutting-edge-technology tools for natural sciences research in the twenty-first century: X-ray free electron lasers

Regarding the chronologic evolution of accelerator-based light sources, optimization and design issues of cutting-edge-technology insertion devices (i.e., undulators, wigglers, etc.) have been a big competitive concern since the beginning of the twenty-first century. Although these sources are strongly restricted by technological limitations in terms of radiation wavelength, leading X-ray free-electron laser (FEL) facilities are spending considerable efforts to survive in this scientific competition by modifying/updating their insertion devices. In other words, even though they all generate almost identical free-electron laser pulses, advertising a 'superconducting undulator based light source' in comparison with a 'conventional undulator based light source' may sound more attractive for some scientists. However, in contrast to superconducting undulators, conventional undulators do not require cryogenic cooling systems resulting in a cost-effective operation as a matter of course. Under the circumstances, it is shown that generation of hard X-ray FEL pulses is feasible via unique PPM undulators driven by an electron linear accelerator (linac) within the energy range of 5 - 10 GeV. The results reveal good consistency with the operating X-ray FEL sources worldwide. (author)