A simple ferromagnetic circuit for a solenoid lens

Several studies have been carried out to explore a simple ferromagnetic circuit to obtain a more intense field inside a solenoid lens. Model experimental results show that, under the circumstance that the ferromagnetic circuit is not saturated and the current remains constant, a more intense magnetic field can be obtained using the semi-enclosed ferromagnetic circuit developed in this paper. The semi-closed solenoid lens is simple, economical and easy to cool and maintain. A semi-enclosed solenoid lens has been manufactured for transporting 50 keV, 50 mA H+ beams at Peking University (PKU). ? 2007 IOP Publishing Ltd.EI1N5-N81