Complex light source composed from subterahertz-wave coherent synchrotron radiation and an infrared free-electron laser at the Laboratory for Electron Beam Research and Application

Abstract

We have successfully transported subterahertz-wave (sub-THz-wave) coherent synchrotron radiation (CSR) from an accelerator room to an experimental room by using an existing IR free-electron laser (FEL) beamline at the Laboratory for Electron Beam Research and Application at Nihon University. The power of the transported CSR was 50 nJ per macropulse, and it was available at frequencies of 0.1-0.3 THz. From two-dimensional imaging performed with the sub-THz-wave CSR, metallic structures concealed by plastic in a smart card were nondestructively detected at a spatial resolution of 1.4 mm. We also verified the existence of hydrated water in a crystal by using chemometric two-band spectroscopy with the sub-THz-wave CSR and IR FEL. Pioneering applications, such as more reliable material identification, can be anticipated from this complex light source composed from the sub-THz-wave CSR and IR FEL beams.

Proposal of coherent Cherenkov radiation matched to circular plane wave for intense terahertz light source

“…Equation (15) shows that the intensity of the CCR-MCP beam saturates at a certain length L C , which is termed the Cherenkov length in this article and is given by…”

“…Fig. 2 shows the dependence of the CCR-MCP intensity, which was calculated using equation (15) at L = L C , on the index of refraction. For all wavelengths, the CCR-MCP intensity exhibits a maximum at n = 2.7.…”

“…The overall intensity of the CCR-MCP beam emitted from the base of the hollow conical dielectric can be evaluated using equation (15). Fig.…”

“…The CSR beam emitted from a bending magnet was injected into the infrared FEL beamline by a flat substrate of LiTaO 3 crystal as a reflector. Because LiTaO 3 crystals have high transmittance for wavelengths ranging from 0.5 μm to 5 μm and high refractive indices in the THz-wave range, the transmitted infrared FEL and the reflected THz-wave CSR could be transported in one beamline [14,15]. The power of the transported CSR was 50 nJ per macropulse.…”

Performance of K -edge subtraction tomography as an application of parametric x-ray radiation

“…The accelerator of LEBRA is a conventional electron linac with a typical energy of 100 MeV. Three kinds of light sources from the THz range to the x-ray region are actualized utilizing the LEBRA linac [2,3]. In particular, the x-ray source with a dedicated beamline is unique; it is based on parametric x-ray radiation (PXR), which is electromagnetic radiation resulting from the interaction between a relativistic charged particle and a crystal medium with periodic structures [4][5][6].…”