Time-of-flight analyzer and method

A time-of-flight mass spectrometer, comprising:

• a sealed housing;
• a vacuum pump for maintaining a vacuum within the sealed housing;
• an ion source within the sealed housing for producing ions;
• one or more electrically-charged accelerating plates within the sealed housing for accelerating pulses of produced ions through one or more accelerating fields;
• a first ion drift region for passing accelerated ions;
• an ion reflection device within the sealed housing for passing reflected ions;
• a second ion drift region within the sealed housing for passing reflected ions;
• the ion reflection device including (a) one or more first electrically charged plates for establishing a first field, (b) one or more second electrically charged plates for establishing a second field downstream from the first field, (c) one or more third electrically charged plates for establishing a third field downstream from the second field, (d) means for adjusting the first and second fields for establishing a substantially uniform flight time for low energy ions through a combination of the first and second drift regions, and (e) means for adjusting the third field independent of the first and second fields for establishing a substantially uniform flight time for high energy ions through the combination of the first and second drift regions, the one or more accelerating fields, and the ion reflection device;
• and
• an ion detector within the sealed housing downstream from the second ion drift region for detecting ions as a function of time.

A method of operating a time-of-flight mass spectrometer including a sealed housing, a vacuum pump for obtaining a vacuum within the sealed housing, an ion source for generating ions, one or more electrically charged accelerating plates for accelerating produced ions through one or more ion accelerating fields, a first ion drift region for passing accelerated ions, an ion reflection device for reflecting ions downstream of the first ion drift region, a second ion drift region for passing reflected ions, and an ion detector downstream of the second ion drift region, the method comprising:

• establishing a first reflecting field within the ion reflection device for reflecting ions of a relatively low energy;
• establishing a second reflecting field downstream from the first reflecting field for reflecting ions of a relatively high energy;
• and
• adjusting the strength of the second reflecting field independent of the first reflecting field for obtaining a substantially uniform ion flight time through a combination of the one or more accelerating fields, the first and second drift regions, and the first and second reflecting fields.