time-of-flight mass analyzer

Abstract

An example of a two-stage reflector will be described. (1) Assuming a reflector composed of a uniform electric field of the base potential XA(U), by adjusting its design parameters to offset the first and second differentials of the entire flight time T(E) when E=E0, and obtain the potential The location of quadratic convergence on the central axis with value E0 (Mamyrin solution). (2) Taking the quadratic convergence position as the starting point, calculate the correction potential XC(U) superimposed on XA(U) such that T(E) of ions reflected on the deeper side of the quadratic convergence position is fixed. (3) Determine the voltage value of the reflective electrode so that the actual potential XR(U)=XA(U)+XC(U) is formed on the central axis. As above, the energy compensation is performed up to the second order with the base potential of the Mamyrin solution, but by superimposing the correction potential, the energy compensation is further extended to an infinite higher order, and complete isochronism is realized for ions reflected at the correction potential part. In addition, the actual potential is smoothly connected before and after the starting point of the correction potential, and the deviation from a uniform electric field is minimized, thus maximally suppressing temporal aberrations caused by divergence and axis deviation of ion trajectories.

Description

technical field [0001] The present invention relates to a time-of-flight mass spectrometer, and more specifically, to a time-of-flight mass spectrometer using an ion reflector (Reflector). Background technique [0002] In a time of flight mass spectrometer (Time of Flight Mass Spectrometer, hereinafter referred to as "TOFMS"), the flight time until the ion beam emitted from the ion source reaches the detector is measured, and the mass of each ion is calculated from the flight time (strictly speaking, is the mass-to-charge ratio m / z). One of the major causes of lowering the mass resolution is the dispersion of initial energies of ions. When the initial energy of ions emitted from the ion source varies, the time-of-flight of ions of the same mass varies, and the mass resolution decreases. To compensate for the time-of-flight dispersion due to the initial energy dispersion of the ion, ion reflectors are widely used. In the following description, a TOFMS using an ion reflecto...

AI Technical Summary

Problems solved by technology

First, when the deviation from a uniform electric field or the curvature of the potential distribution is large, the ion reflector acts as a concave lens, thus causing divergence of ion trajectories and involving a decrease in signal strength

Second, even if the ideal potential can be achieved along the central axis, there will always be a deviation in potential for a trajectory that deviates from the central axis

[0042] As mentioned above, the reason why an ideal reflector cannot be realized even if a one-dimensional ideal potential can be obtained according to previous research and development is because the conventional technology cannot fully satisfy the requirements from to

Images