Liu, X. Gao, Z. He, Y. Huang, G. JACoW Publishing Geneva, Switzerland 2226-0366 978-3-95450-194-6 10.18429/JACoW-LINAC2018-THPO068 English 849-851 THPO068 Contribution to a conference proceedings 2019 2019-01 https://doi.org/10.18429/JACoW-LINAC2018-THPO068 http://jacow.org/linac2018/papers/thpo068.pdf Superconducting RF (SRF) technology is widely ap-plied in particle accelerators to shorten the accelerator length and lower the construction price due to its high acceleration gradients with low rf losses. Field emission is the chief limitation associated with the surface electric field which will finally determine the cavity performance during the operation. The pickup-drop signal caused by field emission seriously affect the stable operation of the superconducting linac in the Chinese initiative Accelera-tor-Driven Sub-critical System (CiADS) demon facility. Simulations of the field emission effect and experimental measurements of the pickup-drop signal have been per-formed on the half wavelength resonator (HWR) cavity. And a modified design of the pickup antenna will be discussed to solve the pickup-drop problem.