| 20110001043 | DETECTOR DEVICE FOR HIGH MASS ION DETECTION, A METHOD FOR ANALYZING IONS OF HIGH MASS AND A DEVICE FOR SELECTION BETWEEN ION DETECTORS - Described here is a detector for measuring heavy mass ions with high sensitivity and low saturation for time-of-flight mass spectrometry and a detector housing for selecting between multiple detectors. It relates to sensitive measuring methods of large masses in the range of about ten thousand to a few million atomic mass units. Specifically it relates to a conversion dynode in a specifically insolated geometry followed by a discrete dynode secondary electron multiplier specifically modified to decrease electron saturation and electronic ringing. Conversion dynode detectors have been used before for time-of-flight mass spectrometry and compared to direct detection with electron multipliers they exhibit superior sensitivity for high-mass, slow-moving macromolecular ions. Using a conversion dynode specifically insolated to a common ground plane has the added capabilities of allowing an increased voltage to be applied to the conversion dynode while maintaining a minimum distance between the conversion dynode and the front of the electron multiplier. This creates faster ion flight time for the secondary ions produced within the detector allowing for higher time resolution and sensitivity from the detector. Also, by adding capacitance as charge buffers to the last few electrodes of a discrete dynode electron multiplier used as a secondary electron multiplier, saturation can be greatly reduced or avoided, which is often a major problem when measuring samples with ions covering a broad mass range. The detector housing described allows multiple detectors to be selected without breaking the vacuum. By keeping all moving mechanical parts inside the vacuum, a more simple, robust and cost effective design can be realized which provides a platform for measuring ions using different detector designs. | 01-06-2011 |
