Relative transmission of different ions through shutter grid

In this work, we study the transmission of different ions through a Bradbury–Nielson type shutter grid which is a key component in ion mobility instruments. It will be shown that the relative transmission of ions through the shutter grid depends not only on the opening time but also on the nature of ion and the voltage applied to the grid electrodes. The transmission of fast moving ions is higher than that of slow moving ions and, in general, applying a voltage greater than the blocking voltage reduces the transmission. A simple model is proposed to explain the results. Since slow-moving ions are lost in greater numbers than fast-moving ones, the intensity of ion peaks decreases as drift time increases. This can be corrected by multiplying the intensities by a factor of (1 + αtd) where α is a small correction factor which depends on the geometry of both the shutter grid and the drift tube and on the opening time.

In this work, we study the transmission of different ions through a shutter grid which is a key part in ion mobility instruments. It will be shown that the relative transmission of ions through the shutter grid depends not only on the opening time but also on the nature of ion and the voltage applied to the grid electrodes. The effect of shutter grid can be corrected by multiplying the intensities by a factor of (1 + αtd) where α is a small correction factor which depends on the geometry of both the shutter grid and the drift tube and on the opening time. In figure the corrected intensities can be seen.Figure optionsDownload high-quality image (63 K)Download as PowerPoint slide