SU392395A1 - AC? COUTH p / "t ^^ ntn0.1Tp [;!? h ^^ m & nd - Google Patents

Description

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This invention relates to the field of mass spectrometry.

A device of Bernhard and Grapener of a similar purpose is known, which is characterized by the fact that the ions passing through the entrance slit of the ion-electron converter enter an inclined uniform electric field and bombard a metal plate parallel to the entrance slit. The secondary electrons are accelerated in a uniform field and bombard the luminescent screen, which is at a high potential.

However, due to the fact that the luminescent screen is at a high potential, special measures of electrical insolation are necessary. In addition, this device works with high-energy ion sources, which requires the use of magnets with a high magnetic field strength.

In order to use ion sources with lower accelerating potential and smaller magnetic fields, eliminate losses of mass spectrum lines in the output window, increase the sensitivity of the ion-electron converter, an accelerating cylindrical single lens is introduced into the proposed device for recording the mass spectrum the extreme electrodes of which are grounded.

The drawing shows a diagram of the device.

The device contains a single cylindrical lens consisting of a plate / slit entering electrode 2, electrodes 3 and 4 (electrodes 2 and 4 are under the potentials of the earth, and a high, negative relative to the earth potential) applied to the electrode 3) a deflecting capacitor formed by the plate 5 and an aluminized luminescent screen. Plate 5 is at the same potential as electrode 3, and the luminescent screen node is at ground potential. The screen is a transparent substrate on which phosphor 6 is applied, covered with a layer of aluminum. Fluorescent screen) zakuumno tightly attached to the chamber of the mass analyzer 7. The entire device is located between the poles of the magnet 8 of the mass analyzer.

The ion beams, separated by a mass analyzer in terms of m / e, located in a plane perpendicular to the plane of the drawing, and cut out in height by a slit in electrode 2, fall into a cylindrical single lens and are additionally accelerated in it. After acceleration, there is a gap in the plate 5,

Ion beams fall into the electric field of a flat Capacitor, deflect in it to the plate 5 and knock out from the surface secondary electrons, which are accelerated by the electric field of the same capacitor. The secondary electrons passing through the aluminum layer cause the phosphor 6 to glow. The mass spectrum is a set of luminous stripes, the intensity of each mass spectral line is proportional to the ion current of the corresponding ion mass. The resulting mass spectrum is recorded by an external recording device, such as a movie camera.

Subject invention

A mass spectrum recording device consisting of a mass analyzer with a straight line of foci and an ion-electron converter with a deflecting capacitor, characterized in that, in order to use ion sources with lower accelerating potential and magnetic fields of lesser intensity, loss of the intensity of the mass spectrum lines in the output window; an accelerating-cylindrical single lens is introduced, the extreme electrodes of which are grounded.