Patent ID: 6960762

Claim:
A mass spectroscope comprising: an ion source for generating ions, a mass spectrometry portion for analyzing the ions, an ion retention portion arranged between the ion source and the mass spectrometry portion for storing, cooling and dissociating the ions, a gas supply connected to the ion retention portion for supplying a gas to the ion retention portion, flow adjusting means disposed between the ion retention portion and the gas supply for adjusting a flow of the gas supplied to the ion retention portion, and control means connected to the flow adjusting means for controlling the flow adjusting means to maintain an inner pressure of the ion retention portion according to operation modes at the ion retention portion, said control means operating the flow adjusting means to introduce the gas into the ion retention portion at a retention operation in which the ions are stored in the ion retention portion so that the inner pressure of the ion retention portion in the retention operation is higher than those in introducing and discharging operations in which the ions are introduced into the ion retention portion and the ions are discharged from the ion retention portion, respectively.