Kutsaev, S.V. Agustsson, R.B. Hartzell, J.J. Murokh, A.Y. Nassiri, A. Savin, E.A. Smirnov, A.V. Smirnov, A.Yu. Sun, Y. Verma, A. Waldschmidt, G.J. Zholents, A. JACoW Geneva, Switzerland 978-3-95450-180-9 10.18429/JACoW-NAPAC2016-TUB3CO04 English 453-456 TUB3CO04 ion gun cathode coupling electron Contribution to a conference proceedings 2017 2017-01 http://dx.doi.org/10.18429/JACoW-NAPAC2016-TUB3CO04 https://jacow.org/napac2016/papers/tub3co04.pdf A thermionic RF gun is a compact and efficient source of electrons used in many practical applications. RadiaBeam Systems and the Advanced Photon Source of Argonne National Laboratory collaborate in developing of a reliable and robust thermionic RF gun for synchrotron light sources which would offer substantial improvements over existing thermionic RF guns and allow stable operation with up to 1A of beam peak current at a 100 Hz pulse repetition rate and a 1.5 μs RF pulse length. In this paper, we discuss the electromagnetic and engineering design of the cavity, and report the progress towards high power tests of the cathode assembly of the new gun.