Zheng, Z. Popielarski, J.T. Saito, K. Stark, S. Xu, T. Yamazaki, Y. JACoW Geneva, Switzerland 978-3-95450-169-4 10.18429/JACoW-LINAC2016-THOP10 English 767-769 THOP10 electron cavity cryomodule controls impedance Contribution to a conference proceedings 2017 2017-05 http://dx.doi.org/10.18429/JACoW-LINAC2016-THOP10 http://jacow.org/linac2016/papers/thop10.pdf The original Fundamental Power Coupler (FPC) of Half-Wave Resonator (HWR) for the Facility of Rare Isotope Beams (FRIB) requires multipacting conditioning at operating RF power which is up to 5 kW Continue Wave (CW). Conditioning takes a lot of time and RF power, and its elimination is highly desirable. To significantly shorten the RF conditioning, we developed a multipacting-free coupler design. This paper reports the latest progress in the optimization and prototype tests of multipacting-free coupler. The choke structure is removed and coupler geometry is further modified to protect the coupler RF window from the electron bombardment. The comparison result of multipacting-free coupler with original coupler was performed on automatic conditioning system, which showed significantly time reducing for RF conditioning.