High speed polarity switch time-of-flight spectrometer

A method of performing mass spectroscopy using a time-of-flight (TOF) analyzer, comprising:

• providing an accelerator stage comprising a first electrode, a second electrode disposed downstream of the first electrode, and a third electrode downstream of the second electrode,
• configuring the accelerator stage of said TOF analyzer to receive and accelerate positive and negative ions during different,cycles for detecting positive and negative ions,
• passing the accelerated positive and negative ions during each of said cycles through a drift chamber,
• detecting at least a portion of the ions after their passage through the drift chamber in each of said cycles,
• maintaining said first and second electrodes at a ground electric potential during a first phase of a cycle for detecting positive ions so as to allow accumulation of a plurality of positive ions in a space between said first and second electrodes,
• applying equal positive voltages to said first and second electrodes during a second phase of said cycle so as to inhibit entrance of additional positive ions into the space between said first and the second electrodes and to create an electric field between the second and said third electrode,
• applying a voltage differential between said first and second electrodes during a third phase of said cycle so as to accelerate the ions accumulated in the space between the first and second electrodes toward said drift chamber, and
• maintaining said first and second electrodes at the end electric potential during a fourth phase of said cycle in which the accelerated ions pass through the drift chamber.