Design and experiment of a laser ionization source for ion mobility spectrometer

The fabrication and characterization of a laser ionization source for ion mobility spectrometer （IMS） is described with the calculated parameter of the drift tube. Ions are created in air at ambient pressure using laser ionization （ A = 248 nm） with air as the drift gas. Mobility spectra for positive ions at different electric fields are obtained with the length of drift tube of 25 and 50 mm, respectively. The distribution of the electric field in the drift tube （50 mm） has also been investigated by SIMION simulation with the ion shutter closed and open respectively.