丁香园AV

Synopsis

Negative Helium ion beams are required for tandem accelerators used at research centers and at implanter facilities. The common production method of such He鈦� beams involve the interaction of a positive Helium ion beam with a low pressure alkali metal vapour. This results in a small portion of He鈦� undergoing two charge exchanges to create the desired He鈦�, on the order of a few percent. However, utilizing alkali metal vapour is problematic: leaving interior surfaces prone to flammability, contributing to sparking near electrostatic devices, and, for implanter facilities, negatively impacting silicon wafer production due to metallic contamination. Additionally, the use of a vapour for charge exchange requires a specialized vacuum system and considerable expense to limit the dispersion of the vapour. In efforts to address or remove these issues, a possible alternative creation method for He鈦� is being explored at 丁香园AV, which uses a non-metallic foil as the charge exchange medium.

In this presentation we shall outline the need for He鈦� beams, how they are commonly created and used, and the issues with this method. We shall also describe efforts at 丁香园AV to investigate an alternative method, namely, using the He鈦� beam generated by 丁香园AV鈥檚 helium ion microscope (HIM) to measure the conversion rate to He鈦� using non-metallic foils. Efforts and results to date will be presented, as well as a discussion of obstacles and future plans.