Our team has been examining several architectures for short-wavelength, coherent light
sources. We are presently exploring the use and role of advanced, high-peak power lasers for both
accelerating the electrons and generating a compact light source with the same laser. Our overall
goal is to devise light sources that are more accessible by industry and in smaller laboratory
settings. Although we cannot and do not want to compete directly with sources such as third-generation
light sources or that of national-laboratory-based free-electron lasers, we have several
interesting schemes that could bring useful and more coherent, short-wavelength light source to
more researchers. Here, we present and discuss several results of recent simulations and our future
steps for such dissemination.
We perform a series of single-pass, one-D free-electron laser simulations based on an electron
beam from a standard linear accelerator coupled with a so-called laser undulator, a specialized device
that is more compact than a standard undulator based on magnetic materials. The longitudinal field
profiles of such lasers undulators are intriguing as one must and can tailor the profile for the needs of
creating the virtual undulator. We present and discuss several results of recent simulations and our future
We present a summary of our team’s recent efforts in developing adaptive, artificial
intelligence-inspired techniques specifically to address several control challenges that arise in
machines/systems including those in particle accelerator systems. These techniques can readily be
adapted to other systems such as lasers, beamline optics, etc… We are not at all suggesting that we
create an autonomous system, but create a system with an intelligent control system, that can
continually use operational data to improve itself and combines both traditional and advanced
techniques. We believe that the system performance and reliability can be increased based on our
findings. Another related point is that the controls sub-system of an overall system is usually not
the heart of the system architecture or design process. More bluntly, often times all of the
peripheral systems are considered as secondary to the main system components in the architecture
design process because it is assumed that the controls system will be able to “fix” challenges
found later with the sub-systems for overall system operation. We will show that this is not always
the case and that it took an intelligent control application to overcome a sub-system’s challenges.
We will provide a recent example of such a “fix” with a standard controller and with an artificial
intelligence-inspired controller. A final related point to be covered is that of system adaptation for
requirements not original to a system’s original design.
We present results on the comparison of different THz technologies for the detection and identification of a variety of
explosives from our laboratory tests that were carried out in the framework of NATO SET-193 “THz technology for
stand-off detection of explosives: from laboratory spectroscopy to detection in the field” under the same controlled
conditions. Several laser-pumped pulsed broadband THz time-domain spectroscopy (TDS) systems as well as one
electronic frequency-modulated continuous wave (FMCW) device recorded THz spectra in transmission and/or
The mechanism of nonlinear harmonic generation in the exponential gain regime, which is driven by bunching at the fundamental wavelength, may provide a path toward both enhancing and extending the usefulness of an x-ray free- electron laser (FEL) facility. Related exotic generation schemes, which exploit properties of harmonic production in various undulator topologies, have been discussed both in the past and more recently. Using three different numerical simulation codes, we explore the possible utility of such schemes (e.g., harmonic afterburners and biharmonic undulators) at future light source facilities.
Construction of a single-pass free-electron laser (FEL) based on the self-amplified spontaneous emission (SASE) mode of operation is nearing completion at the Advanced Photon Source (APS) with initial experiments imminent. The APS SASE FEL is a proof-of-principle fourth-generation light source. As of January 1999 the undulator hall, end-station building, necessary transfer lines, electron and optical diagnostics, injectors, and initial undulators have been constructed and, with the exception of the undulators, installed. All preliminary code development and simulations have also been completed. The undulator hall is now ready to accept first beam for characterization of the output radiation. It is the project goal to push towards full FEL saturation, initially in the visible, but ultimately to UV and VUV, wavelengths.
Over the last few years, there has been a growing interest in self-amplified spontaneous emission (SASE) free-electron lasers (FELs) as a means for achieving a fourth-generation light source. In order to correctly and easily simulate the many configurations that have been suggested, such as multi- segmented wigglers and the method of high-gain harmonic generation, we have developed a robust three-dimensional code. The specifics of the code, the comparison to the linear theory as well as future plans will be presented.