Characteristics of a mass spectrometer using an ion trap detector (ITD) cell

A mass spectrometer using an ITD cell was constructed, and the mass spectru m of Ca+ ions was measured using the mass selective instability scan method . The distance between the two end-cap electrodes and the diameter of the r ing electrode are 14.14 mm (=2z(0)) and 20 mm (=2r(0)), respectively. The f requency of the RF(radio frequency) voltage applied to the ring electrode i s fixed at 1.1 MHz. The optimum value of the He buffer gas pressure for the sensitivity and resolution was experimentally determined to be 3.0 x 10(-4 ) Torr. The possibility of substituting air for the He buffer gas was exami ned.