用于FAIMS系统的法拉第筒离子检测器

Development of a faraday cup ion current detector for FAIMS

介绍了一种应用于FAIMS系统的法拉第筒离子检测器。法拉第筒采用电阻率为1.678×10-8Ω·m的紫铜材料。屏蔽壳尺寸为40×43×37mm3,壁厚为3mm。气路设计为T型,进气口直径Φ6,出气口为双排8×Φ1.6均布小孔。铜敏感极经过化学处理,以提高表面质量与抗氧化能力。与KEITHLEY237电流表级联,测得系统的噪声水平在50fA以下。实验测得FAIMS输出信号为480pA,远远大于系统噪声。该法拉第筒满足了现有FAIMS系统对离子检测器的要求。

A faraday cup ion current detector for FAIMS is described. The faraday cup is made up of copper with resistivity of 1.678×10^8Ωm. Its dimensions are 40×43×37mm^3, with the thickness of 3mm. The T-shaped gas channel has a Ф6 hole as the inlet, and Ф6 holes, designed into 2 rows with 8 holes each, as the outlet. To improve the surface quality and anti-oxidation ability, the copper sensitive part was treated with special chemicals. When combined with KEITHLEY 237 electrometer, the noise level was below 50fA. The output signal of the FAIMS was 480pA, much greater than the noise. The faraday cup meets well with the requirements of the FAIMS.