Li, J. Huang, Z. Mao, L.J. Tang, M.T. Wang, S. X. Yang, J.C. Yang, X.D. Zhao, H. Zhao, L.X. JACoW Geneva, Switzerland 978-3-95450-198-4 10.18429/JACoW-COOL2017-TUP08 English 40-43 TUP08 ion electron target experiment cathode Contribution to a conference proceedings 2018 2018-01 https://doi.org/10.18429/JACoW-COOL2017-TUP08 http://jacow.org/cool2017/papers/tup08.pdf A 13 Tm multifunction storage ring dedicated to nucleon and atomic experiment research - the SRing (Spectrometry Ring) is a significant part of the new heavy-ion research complex - HIAF (High Intensity heavy ion Accelerator Facility). In additional to an electron cooler and a gas internal target planned at the SRing, a beam of low temperature electron is also required to collide with the storage beam and to cool the decelerated ion beam at low energy. A magnetic adiabatic expansion is proposed to attain a low temperature by applying a 1.2 T longitudinal magnetic field upon the thermionic cathode at the electron gun. In this paper, preliminary design of the electron target is introduced.