抄録
High energy proton beam is irradiated to the target made of high atomic number material to initiate nuclear spallation reaction. The nuclear source is used in the experiments of neutron scattering and neutron radiography. The neutron production efficiency decrease due to the intense of increase of the coolant ratio to solid target metal when the proton beam intensity is high. A liquid metal target is effective to solve this problem. In this study, mercury was used as a working fluid in a tube heated by direct electrical current in similar situation as an actual target, and were verified the effects of mercury wettability to the inner surface of the tube on forced convective heat transfer.