Molecular beam laser photoionization time-of-flight mass spectrometer

What is a molecular beam time-of-flight mass spectrometer?
       A molecular beam time-of-flight mass spectrometer is an instrument used to measure atomic or molecular mass. It is included in a high-vacuum system that contains the following regions: (1) molecular beam source region, (2) molecular beam-laser interaction region, (3) ion flight tube region, (4) ) ion detection region.

What is the working principle of a molecular beam time-of-flight mass spectrometer?
       Time-of-flight mass spectrometry is a technique that detects flight time of ions to identify atoms or molecules. When the neutral atoms or molecules are momentarily converted to ions with kinetic energy in the electrostatic field, these ions are accelerated to fly through the zero electric field conduit of about one meter to a particle (ion) detector. Since the flight distance (L) is a known constant, the ion velocity (v = L/t) can be obtained by accurately recording the ion flight time (t). The kinetic energy E of the ion is also a known constant, and the mass of the ion can be obtained from E = (1/2)mv². The measured ion flight time is related to the mass of the atom or molecule.

How to make an in-house time-of-flight mass spectrometer?
       A time-of-flight mass spectrometer is not difficult to make. The time-of-flight mass spectrometer in our laboratory was designed and assembled by ourselves. Some important points have been described in our previous publication: "Determination of laser beam waist using photoionization time-of- flight mass spectrometer", C.R.C. Wang, C.C. Hsu, W.Y. Liu, W.C. Tsai, and W.B. Tzeng, Rev. Sci. Instrum. 65, 2776-2780 (1994).

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