SU1274547A2 - Device for mass spectrometric analysis - Google Patents

Abstract

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Description

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The invention relates to the field of mass spectrometry, energy analysis, electron optics, physical electronics, plasma physics, accelerator technology.

The goal of eradication is to enhance functionality by providing an energy analysis capability.

The energy spectrum of the analyte in the present invention can be obtained in two ways: by the time that the flaHHqfl ions hit the mass on the detector, located. women's line of tricks on energy; where ions of a given mass hit the spatial detector located behind the line (focus on energy, and to increase the energy dispersion between the screen located on the line of energy foci that has an opening and the spatial detector on energy, an inhibiting potential difference is applied,

The ion packets formed and accelerated in the source of ions in a space are separated depending on the mass along their trajectory. When the time-varying field between the electrodes of a flat, cylindrical, or spherical capacitor hits, the ions of different masses will move along different paths, and the ions of the same mass, but having different energy, will be focused on the point lying on the line of foci on energy, the central part which is located between the capacitor electrodes. The position of this point on the line of the energy focus is determined by the mass of the ions in this package. Energy-focused ion packets are detected on the focal line to obtain a spatial mass spectrum.

Detecting the time at which the ion hits a given point on the focal line, the energy spectrum of a given mass of the analyte is obtained. In order to simplify the process of detecting the energy spectrum and increasing the energy resolution, the detection of the ion on the detector is replaced by spatial detection of the energy spectrum. For this, the spatial mass detector has a slit opening into which only ions of a certain mass pass and are detected on a spatial detector located behind the mass detector. Since ions of different energies, but of the same mass,

arrive at the mass detector at one point, but at different angles, they will hit the detector before the energy at a different place, which allows obtaining a spatial energy spectrum of this

masses.

The detector can be made in the form of a microchannel plate, to which a multichannel ion hit time detector is connected.

The microchannel plate has a curvilinear shape that coincides with the line of foci in energy (Fig. 1), the equation of which can be represented in a parametric form

. (",. |". ((",. 1.5.г | р.,.,.

"-1b-%

5.42 & ti

where is i-l / ri o.

L is the length of the span; - the angle between the axis of the span

camera and normal to flat

capacitor electrodes;

plate spacing

a capacitor;

EO is the average energy of ions released

from the source;

m mass of ions;

t "moment of time.

and the coordinate system is chosen in such a way that the OX axis is directed parallel to the capacitor electrodes, the OU axis is perpendicular to them, with this origin coincides with the point of emission of ions from the sources

The position of the energy focus on the focal line depends on the mass of the ion, 5 i.e., the spatial mass spectrum of the analyte is formed on the line. In the event of a failure, the time variation 6t of the Md ion being applied to the focal line depending on the variation of the energy & is defined as

H c-e} () HetP-4) cos, ...

6i.4uJo ()

,) - (f-OjCOS 4 (f-OJ4

i 4i; lge-i), with u 21. Therefore, by registering the time when ions of a given mass hit a certain place on the line of foci, we obtain the energy spectrum of the ionized substance. To simplify the process of detecting the energy spectrum, the detection of ions in time by the spatial detector by spatial detection on an additional screen located behind the line of foci in energy is carried out. For this purpose, the mass detector has a slit hole, into which ions of the same mass pass, but due to the difference in the angles of penetration of ions of different energy to the plane of the hole, an additional screen, ions of different energies will fall into a different place, thereby forming the spatial energy spectrum of the test substance. . The angular dispersion in energy in this case is defined as sin, 8feinf 2 (2cosf.T-oJ.а is linear. Г-У, f where f is the distance from the point on the line of foci corresponding to the given value O, to the additional screen The linear dispersion in energy (, A increases if an inhibitory potential difference is applied between the screen at the research institute and the additional screen. Figure 1 shows the time-of-flight mass spectrometer with the energy spectrum detector, where the source of ions is 1 2, a flat mesh electrode 3, a flat solid electrode 4, a spatial detector 5 in the form of a curvilinear microchannel plate, an energy detector, which is a multichannel detector 6 of the time that ions hit the spatial detector, an electronic switching unit 7, a power source 8. 474 ions, they are separated in the flight chamber and fall into the gap between the flat electrodes, between which the braking potential difference is applied, and fly along parabolic trajectories m. At the moment of time counted from the moment when the ions from the ion source 1 come out of the ion, the potential difference between the flat electrodes 3 and 4 makes the electronic switching unit 7 equal to zero and, since at time t the ions of different mass were located at different points in the space between the flat electrodes 3 and 4 then they fly along different linear trajectories, and the ions of the same mass, but of different energy, are focused on a point on the line, the equation of which is given by the expression {1}. Register the time the ions hit a certain meto. The detector plate 5 uses a high-speed multichannel detector 6 to obtain the energy spectrum of the mass spectrum of the test substance. In order to simplify the process of detecting the energy spectrum, a microchannel plate makes an enormous hole and places behind it an additional screen covered with a photo-emulsion layer. Figure 2 shows the time-of-flight mass spectrometer circuit with detection of the spatial energy spectrum, where an additional screen 9, covered with a photoemulsion layer, an electronic switching unit 10, a source M of power supply. In the proposed time-of-flight mass spectrometer, a packet of ions, a port is: woundedly divided by mass-. energy focus lines,. a certain mass passes through the hole in the microchannel plate of the detector 5, and since ions of different energy come out of the hole at different angles, they will fall on an additional screen 9 in a different place, due to which the spatial energy spectrum of this mass is formed. The turn-off time of the a-field between the electrodes 3 and 4 of the capacitor (t) changes as follows from (), ions of different masses will pass through the hole. Consequently, in this mode, the energy-mass spectrometer will operate as a sequential mass spectrometer iener S1274547. “

State Spectrograph When applying the braking voltage for the energy of the considered potential potential between the microchannels, the curvature of the detector 5 will increase due to the ion trajectory in the telescopic screen 9 of the linear dispersion of the decelerating field.

tfti / g.S