Pressure control of a proton beam–irradiated water target through an internal flow channel–induced thermosyphon

A water target was designed to enhance cooling efficiency using a thermosyphon, which is a system that uses natural convection to induce heat exchange. Two water targets were fabricated: a square target without any flow channel and a target with a flow channel design to induce a thermosyphon mechanism. These two targets had the same internal volume of 8 ml. First, visualization experiments were performed to observe the internal flow by natural convection. Subsequently, an experiment was conducted to compare the cooling performance of both water targets by measuring the temperature and pressure. A 30-MeV proton beam with a beam current of 20 μA was used to irradiate both targets. Consequently, the target with an internal flow channel had a lower mean temperature and a 50% pressure drop compared to the target without a flow channel during proton beam irradiation. •The flow mechanisms inside a proton beam–irradiated water target are elucidated.•A flow channel was designed inside the water target to introduce a thermosyphon.•The pressure of a water target with a flow channel is 50% lower than a target without it.