Storage type ion source

Abstract

The invention relates to the technical field of vacuum electronics, in particular to a storage type ion source, which comprises a cathode, an electron focusing system, an ionization chamber and an electron collector; the electron focusing system is arranged above the cathode, and electrons generated by the cathode form an electron beam current through the electron focusing system; the ionization chamber is arranged between the electron focusing system and the electron collector, grid meshes are arranged on the two sides of the ionization chamber, and a uniform electric field is formed betweenthe ionization chamber and the grid meshes; the electron beam current is ionized by the uniform electric field and then is received by the electron collector. Ions are trapped and stored by utilizingthe space charge effect of electrons, so that the initial states of the ions have good consistency, and the stability and uniformity of an ion beam are greatly improved when an ion source is led out.

Description

technical field [0001] The present application relates to the technical field of vacuum electronics, in particular, to a storage type ion source. Background technique [0002] Ion sources are widely used in mass spectrometers, surface coatings, ion thrusters and other fields. Improving the stability and uniformity of ion beams has become an important trend in technology development. For example, for time-of-flight mass spectrometers, ion energy and spatial uniformity are directly Affects performance parameters such as instrument resolution and sensitivity. [0003] There are many types of ion sources. Traditional electron collision ion sources are usually used in the ionization of gas molecules. The energy of electrons usually reaches about 70eV. The ions generated by ionization are evenly distributed in the entire ionization space. When the introduction voltage is applied or the repulsion voltage is increased, the ions are pulled out of the ionization chamber to form an io...

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Problems solved by technology

[0004] The trajectory controllability of the electron beam focusing introduced by the traditional electron collision ion source is poor, and the initial position of the initial ion generated by the electron collision is relatively scattered. and time difference

These problems limit the development of ion source technology, and also limit its application in the field of high-end measuring instruments or analytical instruments

like figure 1 As shown, S.Sheridan et al. proposed a carbon nanotube cathode impact ionization source applied to a space mass spectrometer (see "S.Sheridan, M.W.Bardwell, A.D.Morse et al.A carbon nanotubeelectron impact ionization source for low- power, compact spacecraft massspectrometers.Advances in Space Research, 2012; 49: 1245), the electron source’s outgoing electron energy reaches hundreds of electron volts, and the carbon nanotube cathode area is 0.5mm 2 , the ionization efficiency is relatively low. After the electrons are extracted, they randomly collide with ionized gas molecules, and the ions are directly introduced into the mass analyzer. The uniformity and stability of the ion beam are poor.

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