Radio frequency negative ion source for secondary ion mass spectrometer

Abstract

The invention discloses a radio frequency negative ion source for a secondary ion mass spectrometer. The radio frequency negative ion source comprises an ion source body, a radio frequency injection assembly and an ion beam lead-out system, wherein the ion source body comprises a discharge cavity and a packaging magnet disposed outside the discharge cavity, and the packaging magnet comprises a plasma confinement part and an offset magnetic field generation part which are distributed in the axial direction of the discharge cavity; the radio frequency injection assembly comprises a gas source supply part and a radio frequency injection part, the gas source supply part feeds working gas into the discharge cavity, and the radio frequency injection part is installed on the front end side of theion source body and emits radio frequency into the discharge cavity; the ion beam lead-out system comprises a plasma electrode, an extraction electrode and a ground electrode which are sequentially arranged from front to back; a first lead-out hole is formed in the plasma electrode, a second lead-out hole is formed in the extraction electrode and a third lead-out hole is formed in the ground electrode; the plasma electrode is used for modulating the state of plasma; the extraction electrode is used for preliminarily accelerating the led-out negative ion beam and adsorbing electrons; and the ground electrode is used for accelerating the negative ion beam to target energy.

Description

technical field [0001] The invention relates to a radio frequency negative ion source for a secondary ion mass spectrometer. Background technique [0002] The secondary ion mass spectrometer has high precision, high sensitivity, high resolution, and high efficiency micro-area in-situ isotope and elemental analysis capabilities, and has a wide range of applications in the fields of earth science, material science, marine science, nuclear science, and life science. It is one of the most advanced large-scale micro-area in-situ analysis instruments in the world. [0003] At present, the ion source widely used in secondary ion mass spectrometer is dual plasma ion source, which is used to generate O - , O 2 - Ions can be used for scientific research in fields such as geochronology. Geochronological analysis mainly uses radioactive isotopes to determine the formation age of different types of rocks and deposits. The target test ions are electropositive radioactive isotope ions....

AI Technical Summary

Problems solved by technology

However, there are some problems in using dual plasma ion sources to generate O- and O2- ion beams on secondary ion mass spectrometers, such as : ① poor stability of the ion source (fluctuation > 10%); ② limited life of the ion source (50-200 hours); ③ large energy dispersion is not conducive to the formation of small beam spots (energy dispersion 5-20eV, beam spot 10-30μm); ④ Few types of ions (negative oxygen)

Therefore, it is urgent to equip the secondary ion mass spectrometer with a higher performance ion source to improve the brightness and spatial resolution of the ion beam, otherwise it will be powerless for the research of many frontier fields and hot issues

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