Negative ion beam extraction in volume mode on the RF negative ion source at ASIPP

This paper reports on several recent modifications made to HUNTER, including magnetic confining field, magnetic filter field, extraction area, pumping system, RF generator, high voltage power supply.

And then, the performance of negative hydrogen ion beam extraction in volume mode without Cs seeding was reviewed and compared to the former commissioning results. The current of extracted negative ions and co-extracted electrons were recorded by the Hall current sensors installed on the electric wires connecting to the extraction grid, and ground grid and calorimeter. A similar extraction experiment from argon plasma verified the effective deflection and absorption of co-extracted electrons on the extraction grid, where the leaking electrons were less than 2%.