Smirnov, A.V. Agustsson, R.B. Berg, W. Borland, M. Boucher, S. Bruns, W. Campese, T.J. Chen, Y.C. Dooling, J.C. Erwin, L. Hartzell, J.J. Jacobson, B.T. Lindberg, R.R. Murokh, A.Y. O'Shea, F.H. Pasky, S.J. Sereno, N. Spranza, E. Sun, Y. Zholents, A. de Loos, M.J. van der Geer, S.B. JACoW Geneva, Switzerland 978-3-95450-180-9 10.18429/JACoW-NAPAC2016-WEPOB48 English 998-1000 WEPOB48 ion radiation undulator electron experiment Contribution to a conference proceedings 2017 2017-01 http://dx.doi.org/10.18429/JACoW-NAPAC2016-WEPOB48 https://jacow.org/napac2016/papers/wepob48.pdf Design features and experimental results are presented for a sub-mm wave source [1] based on APS RF thermionic electron gun. The setup includes compact alpha-magnet, quadrupoles, sub-mm-wave radiators, and THz optics. The sub-THz radiator is a planar, oversized structure with gratings. Source upgrade for generation frequencies above 1 THz is discussed. The THz radiator will use a short-period undulator having 1 T field amplitude, ~20 cm length, and integrated with a low-loss oversized waveguide. Both radiators are integrated with a miniature horn antenna and a small ~90°-degree in-vacuum bending magnet. The electron beamline is designed to operate different modes including conversion to a flat beam interacting efficiently with the radiator. The source can be used for cancer diagnostics, surface defectoscopy, and non-destructive testing. Sub-THz experiment demonstrated a good potential of a robust, table-top system for generation of a narrow bandwidth THz radiation. This setup can be considered as a prototype of a compact, laser-free, flexible source capable of generation of long trains of Sub-THz and THz pulses with repetition rates not available with laser-driven sources.