Time-of-flight mass spectrometer and method for improving mass and spatial resolution of an image

A method for improving mass and spatial resolution of an image, comprising:

• selecting a plurality of analyzed ions mass range from a sample on a sample holder 112 by a selection of time when an ion gate 113 for passing a plurality of ions inside of an ion mirror trap 104 is open and time when the ion mirror trap 104 is closed;
• receiving the plurality of ions with a primary component of velocity along a first direction to the ion mirror trap 104 and decelerating the plurality of ions until no velocity in the first direction at back of the ion mirror trap 104 and then reflecting the plurality of ions back such that the plurality of ions is accelerated in a second direction that is opposite to the first direction and backs out of the ion mirror trap 104;
• traveling the plurality of ions with bigger velocities in the first direction and the second direction takes more time than the plurality of ions with lesser velocities, whereas in focusing electrostatic lenses 109, 110 ions with bigger velocities take lesser time than the plurality of ions with lesser velocities;
• bouncing selected ion with a specified mass to charge ratio allow increase ions path of flight and accordingly control in a wide range of the ion mass resolution;
• compensating time arriving disturbance in an image plane of an ion detector 111 by a combination of focusing and mirroring ion optical components, the focusing and mirroring ion optical components comprising an object lens 105, an entrance module 107, a first electro statistic transport lens 109, a second electro statistic transport lenses 110, an exit module 108, and a projection lens 106 and the ion detector 111;
• and
• improving mass and spatial resolution of an image on the image plane of the ion detector 111 by the combination of focusing and mirroring ion optical components with corrected geometrical, chromatic, and timed aberrations.

A method for correcting timing, chromatic, and geometrical aberrations, comprising:

• extracting a plurality of ions from a sample on a sample holder 112 to an ion mirror trap 104 when the plurality of ions has minimum energy spread;
• applying positive voltages or negative voltages to an ion gate 113 for allowing to pass or reject the plurality of ions through an opening of the ion gate 113;
• setting an entrance module 107 and an exit module 108 of an ion mirror trap 104 in a focus mode to create an ion optical image of the sample on the sample holder 112 on an image plane of the ion mirror trap 104 located in an image plane of a field view aperture 114 by an electrostatic object lens 105, a first transport electrostatic lens 109, a second transport electrostatic lens 110, the entrance module 107, and the exit module 108;
• passing the plurality of ions through the entrance module 107 and the exit module 108 and focusing the plurality of ions on an image plane of the ion mirror trap 104 or an ion detector 111, whereas when the entrance module 107 and the exit module 108 set in a mirror mode, then the plurality of ions traveling from the image plane of the ion mirror trap 104 reflected in the entrance module 107, and the exit module 108 and traveling back the image plane of the ion mirror trap 104;
• guiding and mapping the plurality of ions from the sample on the sample holder 112 to the image plane of the ion mirror trap 104 by the electrostatic object lens 105, the first transport electrostatic lens 109, the entrance module 107 of the ion mirror trap 104 in the focus mode, whereby the second transport electrostatic lens 110, the exit Module 108 in the focus mode and projection lens 106 focusing and mapping the plurality of ions from the image plane of field view aperture 114 to the image plane of the ion detector 111;
• creating an ion optical image from the image plane of the ion mirror trap 104 on the image plane of the ion detector 111 after arranging the projection lens 106 in congestion with the exit module 108 of the ion mirror trap 104;
• serving the first transport electrostatic lens 109 and the second transport electrostatic lens 110 for an image position adjustment of the entrance module 107, and the exit module 108 for the focus mode and the mirror mode;
• detecting the time arrivals of the plurality of ions emitted from the sample on the sample holder 112 by the ion detector 111;
• and
• minimizing timing, chromatic, geometrical aberrations of spatial detection properties of the ion detector 111.