限口法拉第筒的研制

Limited opening faraday cup

自行研制了一种限口法拉第筒,用于确定20 MeV以下能量质子入射到不同材料中的吸收剂量。与传统法拉第筒相比,限口法拉第筒的改进在于:抑制电极由外筒和回弯环两部分构成,回弯环改变了法拉第筒的电场分布,增强了电场对次级电子的束缚能力.减小了对入射离子束的影响,提高了测量的准确度。

A limited opening faraday cup （LOFC） was designed to determine the absorbed dose in different materials of incident proton with energy below 20 MeV. Compared with the traditional FC, the main difference is on the suppressor electrode, which is composed of the outer cup and the tight circle. The distribution of electric field is influenced by the tight circle that could suppress the ejection of secondary electrons effectively, without affecting the ion beam. And this improves the accuracy of FC.