Method and device for measuring gas cluster ion beam mass spectra

Abstract

The invention provides a method for measuring gas cluster ion beam mass spectra. Cluster ions form a pulsed ion beam through an electrostatic capacitor, the pulsed ion beam is sprayed to a Faraday cupconnected to a field effect transistor (FET) source follower, and an oscilloscope is used to measure signals generated by cluster ions of different masse respectively in the pulsed ion beam, and TOFmass spectra of the cluster ions are obtained by TOF mass spectrometry. The invention also provides a device for measuring gas cluster ion beam mass spectra based on the measuring method. The device includes the Faraday cup for receiving the pulsed ion beam, the FET source follower connected with the Faraday cup and the oscilloscope. According to the method, by taking a field effect transistor asthe source follower and adopting the special design of directly connecting the field effect transistor with the Faraday cup, a time constant of a detector is reduced, so that detector response sensitivity is effectively improved, the mass spectrum resolution is improved, and the perfect ion beam mass spectra are obtained.

Description

technical field [0001] The invention relates to a measurement method and device for gas cluster ion beam mass spectrometry, belonging to the technical field of gas cluster ion beam measurement. Background technique [0002] A cluster is a particle containing several to thousands of atoms, belonging to the sub-nanometer or nanometer scale, and can be produced in solid, liquid, and gaseous substances. When a cluster ion beam with a certain speed interacts with a solid surface, it will produce significantly different effects from monatomic ions and molecular beams: high mass-to-charge ratio, lateral sputtering effect, multiple scattering phenomenon, and in the same ion In the case of beam current, cluster ions can transport more substances. The lateral sputtering effect is beneficial to the smoothing of the sample surface, and the high mass-to-charge ratio can effectively reduce the Coulomb repulsion energy between particles during the transport process. Therefore, cluster io...

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Problems solved by technology

However, with the current equipment, a standard oscilloscope is usually used to directly measure the Faraday cup signal, the time constant τ = 1000000Ω × 150pF = 150μs, and the drift time t is generally tens of μs, which obviously does not satisfy τ<<t, it is difficult Satisfying this requirement will result in large errors in TOF mass spectrometry and low resolution, which cannot meet the research requirements

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